Some people hit their stride in the morning, while others feel most awake and productive at night. But a growing body of evidence suggests that being part of the latter group, the "night owls," could be linked to poorer heart health.

Now, a large study published Jan. 28 in the Journal of the American Heart Association adds weight to the idea.

Pulling from the UK Biobank, a massive repository of data from U.K. adults, researchers followed more than 322,000 adults ages 39 to 74 for nearly 14 years. They examined how "chronotype" — whether someone is a morning or evening person — relates to their cardiovascular disease risk.

The participants reported their preferred sleep-wake schedules and were classified as morning, intermediate or evening types. Heart health was assessed using the American Heart Association's Life's Essential 8 score, which rates heart health on a scale of 0 to 100 based on eight factors: smoking, diet, exercise, blood sugar, body weight, blood pressure, cholesterol and sleep quality. Higher scores indicate better cardiovascular health.

Compared with intermediate sleepers, "definite evening" types were 79% more likely to have poor overall scores and had a 16% higher risk of heart attack or stroke over about 14 years of follow-up. "Definite morning" types were 5% less likely than intermediate sleepers to have poor scores.

But what's behind this link? Does something about night owls' lifestyles set them up for worse heart health, or is there something unique about their biology that plays a role?

How lifestyle may factor in

The night owls scored worse on various lifestyle-related factors, compared to the intermediate sleepers in the biobank study. For example, they had 54% higher nicotine exposure, 42% poorer sleep, 19% lower physical activity, and 8% poorer diet. In contrast, the morning people generally had lower nicotine use and better diets than intermediate types did.

When these differences were taken into account, about 75% of the increased cardiovascular risk observed in night owls appeared to be linked to lifestyle factors, rather than to the chronotype itself. Among these factors, smoking contributed the most (34%), followed by poor sleep (14%), high blood sugar (12%), and diet and body weight (11% each).

"The drivers of overall cardiovascular health are modifiable, including nicotine exposure," study lead author Sina Kianersi, a postdoctoral research fellow at Brigham and Women's Hospital and Harvard Medical School, told Live Science in an email. Other influential lifestyle factors included physical activity levels, blood pressure and cholesterol, he added.

"So for people who identify as night owls, it is a good reason to be even more proactive about those basics," he said.

Prior studies have suggested that night owls often experience social jet lag, a mismatch between their internal clock and their daily routines. This mismatch may be associated with habits like late-night eating, skipped breakfasts, irregular sleep and a greater reliance on caffeine or nicotine. In turn, these behaviors have been linked to factors that raise heart disease risk, such as higher body mass index (BMI), elevated blood sugar, higher insulin resistance, and lower levels of good cholesterol.

Past research also indicates that, even if they get a decent amount of sleep overall, adults with irregular sleep patterns have a 26% higher risk of stroke, heart attack, or heart failure than those with regular sleep patterns.

"Fragmented or insufficient sleep can raise blood pressure, cholesterol, and blood sugar, often with weight gain," Dr. Bibhu Mohanty, an associate professor at the University of South Florida who was not involved in the research, told Live Science in an email. "This is largely driven by [the stress hormone] cortisol, which mobilizes sugar and fat in ways that can make disease harder to reverse, once it is established."

The biology of night owls

Being a night owl isn't a choice — it's partly written in people's genes.

Studies have linked hundreds of genetic variants to chronotype. Many of the highlighted genes are involved in regulating the body's 24-hour clocks, or circadian rhythms. These rhythms help control sleep, appetite, hormone cycles and heart function throughout the day and night.

People with late chronotypes often have delayed circadian rhythms. That means their levels of melatonin, the sleep-promoting hormone, rise later in the evening than they do in early chronotypes. In turn, their cortisol, which helps wake up the body, rises later in the morning than usual.

This shift can throw the body out of sync with the normal day-night cycle, making the body’s fight-or-flight system overactive. As a result, blood pressure can stay high at night, and inflammation and oxidative stress increase. Over time, these changes can damage blood vessels, disrupt blood sugar, and promote plaque buildup in the arteries, which may manifest as heart disease, studies suggest.

Many of the genes involved in determining chronotype also directly affect lipid and glucose metabolism, or how the body breaks down fats and sugars. Studies show that evening types show altered expression of these "clock genes" alongside elevated inflammation markers and triglycerides, a type of fat, compared to morning types. These patterns may contribute to metabolic issues like insulin resistance and poor cholesterol, which are known heart disease risks, though more research is needed to confirm the direct link.

Early evidence also suggests subtle differences in heart structure and function in night owls, though the long-term effects of these differences are still being studied.

Questions to address

Some data from the UK Biobank study suggest the link between night owls and poorer heart health may be stronger in females than in males. Female night owls were 96% more likely, and male night owls 67% more likely, than their intermediate chronotype counterparts to have a poor overall cardiovascular health profile, according to the LE8 score.

Kianersi said, "This difference could reflect social pressures, biology, or both. It's a signal that deserves further study."

Even though the UK Biobank study found a link between the chronotype and poorer heart health, being a night owl doesn't doom you to cardiovascular disease.

"We need studies that get closer to cause and effect, using approaches like genetics as well as intervention research," Kianersi said. "And it will be important to see if these patterns hold in younger adults and in other populations with different work schedules and environments."

For night owls looking to protect their hearts, Mohanty advises focusing on improving lifestyle habits whenever possible.

"That means developing healthier sleep routines, exercising, making healthy dietary choices, avoiding unnecessary snacking and smoking, and potentially using medication to reduce risk if needed," he said. Approaching heart health holistically is "probably the best approach to limit risk."

This article is for informational purposes only and is not meant to offer medical advice.

Cannabis smoke can seem gentler than tobacco's, but that impression of marijuana may be deceptive. Deep in the lungs, the drug's chemistry is far from benign, recent research suggests. Some studies have even linked heavy cannabis use to a heightened risk of some cancers, including those of the head and neck.

So is there a clear link between cannabis and cancer, and if so, what causes it?

Each lungful of cannabis smoke is a brew of the high-inducing ingredient tetrahydrocannabinol (THC), fine particulates, and certain carcinogens that are also found in tobacco. But cannabinoids may bring their own twist by quietly rewiring the lungs' immune settings.

"The airway's protective lining weakens, antiviral signals falter, and inflammation flares," said Raphael Cuomo, a scientist working at the intersection of cancer prevention and addiction at the University of California, San Diego. In one study with mice, cannabis smoke dulled both tumor-fighting and infection defenses. In another, THC blunted the effects of immunotherapy, weakening tumor-killing immune cells in the body.

Cannabis also triggers other changes in the immune system, according to studies in humans, cells and lab mice. In the airways, levels of proteins tied to inflammation spike when cannabis is used consistently. A protein called MUC5AC, which lines and protects the respiratory tract, is made in excess in certain cells, hinting at early tissue changes. Cannabis smoke can skew the enzymes that maintain tissue and switch off genes that respond to toxins.

The responses of the lungs' patrol cells — alveolar macrophages — can be stunted. And in the blood, shifts in cellular messengers called cytokines and faint changes in epigenetics become a molecular diary of exposure.

Related: Could cannabis treat cancer someday? Here's what the science says so far

In summary, "cannabis smoke, from its toxic byproducts to THC, can irritate lungs and weaken immunity," Sayantan Bhattacharyya, a cancer systems biologist who will soon be a senior postdoctoral scientist at the University of Limerick in Ireland, told Live Science.

But immune disruption is only one factor that might raise cancer risk. Cannabis smoke may also tug on deeper levers inside cells — the molecular switches that cancers use to grow and spread.

Among these, few are as infamous as the epidermal growth factor receptor, or EGFR. In one of the few studies of its kind, Bhattacharyya examined 83 men with glottic cancer, which affects the voice box, and found that cannabis smokers in the group had markedly higher activation of EGFR and related cancer proteins than either tobacco smokers or nonsmokers.

"EGFR governs [cell] growth, repair, and survival," Bhattacharyya said. "In cannabis smokers, constant activation can fuel unchecked proliferation, speed genetic damage, and hasten the leap toward cancer — triggering earlier onset, faster spread, and treatment resistance." That said, Bhattacharyya's study included only 83 people with one type of cancer, so more work is needed to know if the results are broadly applicable.

Bhattacharyya sees two priorities for future research. One is to develop realistic lab models — such as "organoids," 3D-printed tumors and organ chips — to study how cannabis amplifies EGFR. The other is to probe potentially dangerous additives that might be lurking in unregulated cannabis products, he said.

For all the unsettling biology uncovered in laboratory studies, real-world studies of cannabis smokers tell a mixed story. Some research links heavy cannabis use to higher cancer risk, while others find no clear connection. Still, Cuomo maintains that long-term use of the drug may increase the odds of developing cancer, based on what we know so far.

For people who already have cancer, however, Cuomo has shown that cannabis use isn't linked to an earlier death — a puzzle researchers now call "Cuomo's paradox." In fact, studies have found that, in cancer patients, cannabis can boost appetite and curb chemotherapy-induced nausea, even as its smoke may potentially be planting the chemical and cellular seeds of disease.

The challenge going forward will be to accurately assess both the benefits and harms of cannabis in order to weigh them against one another.

Editor's note: This story was updated on Aug. 21, 2025, to note that Bhattacharyya will hold a position at University of Limerick.

This article is for informational purposes only and is not meant to offer medical advice.

Because eating a cannabis-infused brownie or gummy does not involve inhaling smoke, it may be tempting to think of edibles as a relatively harmless high. However, new research suggests that similar to smoking cannabis, consuming edibles containing the compound tetrahydrocannabinol (THC) may worsen cardiovascular health over time.

The study found that "chronic smokers of marijuana have poorly functioning blood vessels similar to chronic smokers of tobacco," said Matt Springer, a cardiovascular researcher at the University of California, San Francisco (UCSF) whose lab led the new study. "THC edibles also appear to be associated with this problem."

Published May 28 in the journal JAMA Cardiology, these findings may counter commonly held beliefs about the health impacts of weed.

"A lot of people consider marijuana to be totally safe for the cardiovascular system," said Dr. Robert Kloner, director of cardiovascular research at Huntington Medical Research Institutes in Pasadena, California, who was not involved in the new study.

Although scientists have not reached total consensus about the health effects of cannabis, Kloner added, the UCSF study adds to the mounting evidence that the drug contributes to the risk of cardiovascular events, such as heart attacks and strokes. This is especially true for people with coronary artery disease or with other risk factors, such as a high blood pressure or diabetes, that may lead to arterial narrowing.

Cannabis and heart health

To better understand how cannabis affects cardiovascular health, Springer and his colleagues recruited 55 adult participants who fell into three groups: cannabis smokers, THC edible users and cannabis nonusers. To isolate the effects of habitual cannabis smoking or edible use, the study focused on cannabis users who reported using the drug at least three times a week, exclusively through their preferred method.

The study's lead author Dr. Leila Mohammadi, a physician-scientist at UCSF, noted that their study's strict recruitment criteria resulted in a small sample size, which could somewhat limit the findings. However, it also enabled them to rule out other factors that could affect people's blood vessels, such as tobacco use or underlying health conditions.

To gauge each participant's vascular function, the authors temporarily blocked blood flow to the brachial artery — located in the upper arm — with an inflatable forearm cuff. They used ultrasound imaging to measure the artery's diameter before and after releasing this pressure. This measure is reflected as the percentage of diameter change from the baseline measurement.

Springer said this test offers a "window into the future" because if blood vessels cannot dilate properly in response to increased blood flow, that's linked to a higher risk of poor cardiovascular disease outcomes, such as heart attack.

Among the participants who did not consume cannabis, the researchers measured an average vessel dilation of 10.4%. By comparison, cannabis smokers and edible users had an average dilation of 6.0% and 4.6%, respectively. This decrease in dilation is similar to what the researchers observed in an earlier study of chronic tobacco smokers.

The more cannabis people used — as defined by the number of smoking sessions or milligrams of THC consumed via edibles per week — the more dramatic their impairment in dilation was.

To uncover clues as to why cannabis might cause this change in function, the researchers ran a laboratory study to see how the participants' blood samples affected endothelial cells. These cells line blood vessels and release compounds, such as nitric oxide, that spur vascular dilation.

This vessel-widening process can be triggered by a substance called vascular endothelial growth factor (VEGF). But when the researchers exposed endothelial cells in lab dishes to blood samples from cannabis smokers, they found that the blood hampered VEGF-stimulated nitric oxide production in the cells.

However, blood from edible consumers and cannabis nonusers had no effect on the cells' nitric oxide release. That suggests that cannabis smoke and ingested THC affect the cardiovascular system via separate mechanisms. That idea is in line with a prior study from the same team, which found that secondhand cannabis smoke that was stripped of THC still affected the blood vessels of rats that breathed it in.

The new study revealed only an association between cannabis use and vascular function, not definitive proof of how the drug affects blood vessels, Springer acknowledged. Meanwhile, one of his collaborators previously reported that cannabis appears to harden blood vessel walls but does not affect vascular dilation, whereas the current paper reports the opposite findings. So there's more research to be done.

Springer added that because they only recruited habitual users of the drug, people who consume cannabis less frequently may not be affected the same way.

Cannabis is becoming available to a growing number of consumers thanks to efforts to legalize the drug at the state level. However, research into its health effects has not kept up, Kloner said. Because the drug is still illegal at the federal level, cannabis studies remain constrained by strict regulation, making the drug more difficult to study, he noted.

This article is for informational purposes only and is not meant to offer medical advice.

For the first time, the U.S. Food and Drug Administration (FDA) has authorized the marketing of nicotine pouches, synthetic packs of nicotine designed to be placed under a person's lip.

In a statement published Jan. 16, the agency stated that 20 different Zyn nicotine pouch products can now be marketed to adults ages 21 and over. That doesn't mean the pouches are now "FDA approved" as drugs intended to treat disease would be, nor that they are safe. Rather, the pouches have met the FDA's criteria for nicotine-based products that can be sold to the public.

After an "extensive scientific review," the FDA said the pouches have met the public health standard set by the 2009 Family Smoking Prevention and Tobacco Control Act, which weighs the overall risks and benefits that such products would pose to the general population. The agency notes that the pouches contain lower levels of harmful substances than cigarettes do and thus pose a lower risk of cancer and other serious health issues.

However, some public health and medical organizations claim that by authorizing the marketing of these products, the FDA has ignored their warnings about how dangerous the products could be to young people. Meanwhile, other experts have cautioned that there is not yet enough scientific evidence to support their use as a smoking cessation tool. The FDA's statement suggests that the pouches could be helpful in the event that people who smoke completely switch to the pouches instead.

Here's everything we know so far about nicotine pouches and the new FDA authorization.

Related: Simple vaping 'quitline' can help over 40% of young people quit, study finds

What does the FDA authorization mean?

The new FDA authorization means that 10 flavors of Zyn nicotine pouches can now be legally marketed in the U.S. to adults ages 21 and over. These 10 flavors come in two nicotine doses: 3 and 6 milligrams. The company markets these flavors as chill, cinnamon, citrus, coffee, cool mint, menthol, peppermint, smooth, spearmint and wintergreen.

In its Jan. 16 statement, the FDA notes that this latest authorization does not mean that these products are safe for use or that they are "approved" by the agency. This is as opposed to several types of nicotine-replacement therapies, including "nicotine gum" and "nicotine patches," which have been approved by the FDA as quit-smoking aids. These latter products have been shown are much less addictive than cigarettes, don't cause death or disease and are usually only used temporarily.

Products like Zyn don't need to be proven safe and effective for a specific population — the manufacturer just needs to comply with "requirements under the law to bring its product to market," the FDA website says. In addition, the FDA assesses whether a given product would offer more benefits than risks to the general population, considering the population as a whole, including users and nonusers of tobacco products. It weighs, for example, whether people who currently smoke might benefit from switching to the new product, or if nonusers might be likely to start using nicotine for the first time once the new product hits the market.

What are nicotine pouches?

Nicotine pouches like Zyn are small, rectangular bags of powder that are placed between a person's lip and gums to deliver nicotine. They don't contain any of the tobacco found in conventional smoking products, such as cigarettes and cigars. Nicotine from the pouches enters the bloodstream and makes its way to the brain via the oral mucosa — the wet, soft tissues that line the mouth.

"Nicotine pouches are a relatively new category of tobacco products that are unique because they contain a crystallized nicotine powder instead of tobacco leaf," Tory Spindle, an associate professor of psychiatry and behavioral sciences at Johns Hopkins Medicine, told Live Science in an email.

"This means that they generally contain fewer harmful ingredients compared to traditional tobacco products," he said. Products like cigarettes contain both tobacco and a variety of additives, both of which contain carcinogens.

But nicotine pouches aren't free of harmful chemicals. "They do still contain nicotine which is an addictive substance as well as other substances such as flavorants," Spindle said. A study published in the journal Tobacco Control in 2022 found that 26 of 44 sampled nicotine pouch products contained cancer-causing chemicals known as tobacco-specific nitrosamines. The nicotine in the pouches can be derived from tobacco plant extracts, explaining how these chemicals end up in the products.

The same study also found that each of the sampled pouches contained between 1.79 and 47.5 mg of nicotine. By comparison, cigarettes contain an estimated 6.17 to 12.65 mg and e-cigarettes release about 0.5 to 15.4 mg per 300 puffs, while nicotine patches or gum release up to 21 mg or 4 mg of nicotine. So, depending on the brand, nicotine pouches still deliver substantial amounts of nicotine compared with other products on the market.

Can nicotine pouches help people quit smoking?

For a product to receive marketing authorization, there needs to be sufficient evidence that it offers greater benefits than risks to the health of the general population, Matthew Farrelly, director of the Office of Science in the FDA's Center for Tobacco Products, said in the agency's Jan. 16 statement.

"In this case, the data show that these nicotine pouch products meet that bar by benefiting adults who use cigarettes and/or smokeless tobacco products and completely switch to these products," Farrelly said.

However, experts are unconvinced that there is enough scientific evidence to support the idea that adult smokers will actually make the switch.

Related: Nicotine vapes are one of the best tools to help people quit smoking, review of 300 trials suggests

"There are some anecdotal reports of people switching from smoking or using traditional oral tobacco products such as 'dip' or 'chew' to nicotine pouches," Spindle said. "But the gold standard research studies needed to answer this question (randomized controlled trials) have not been done."

Randomized controlled trials allow scientists to directly assess whether one factor causes another. In this case, such a trial would likely involve a large group of people who currently smoke, a percentage of whom would be given nicotine pouches to see whether they're more likely to quit than people given a different intervention or nothing at all.

One recent scientific review, published in 2024 in the journal Experimental and Clinical Psychopharmacology, suggested that oral nicotine pouches may be a "viable harm reduction" option for people who switch over completely from conventional tobacco products. However, that review also concluded that randomized controlled trials are needed to determine if people will continue to use the pouches in the long term. More independent research on the topic, not funded by the tobacco industry, is also needed, the review states.

What are the potential risks of using nicotine pouches?

Nicotine pouch use is associated with several health effects, including addiction to the nicotine within them, Spindle said. These effects can be particularly pronounced for younger people, who may still use the products despite the new authorization only allowing marketing towards over-21s.

"Developing an addiction to a substance can have negative impacts on the developing brain, which is why it is important for kids not to use them," Spindle said. Exposure to nicotine during adolescence can alter signaling between neurons in the prefrontal cortex of the brain. This part of the brain controls an array of cognitive functions, including decision-making and reasoning, and it's one of the last regions of the brain to mature.

Nicotine pouches are also known to cause side effects, such as nausea and mouth sores. Because they don't include all of the harmful substances found in traditional tobacco products, some people might assume that the pouches have fewer long-term health effects. However, that's not known for sure, and their impact on oral health is particularly unclear, Spindle said.

The FDA says it will "closely monitor the marketing and use of these products," according to the Jan. 16 statement. This monitoring will include ensuring that the marketing of the patches online, on TV and on the radio is targeted to adults ages 21 and over.

But several organizations have raised concerns about whether this level of regulation will be enough to curb the use of nicotine pouches by younger groups. The flavors of authorized Zyn products are likely to appeal to this demographic, the organizations noted.

"While it has not been sold in the U.S. for long, we are already seeing very concerning levels of youth use [of Zyn], and troubling use of influencers and celebrities to promote the product," the American Lung Association said in a statement released Jan. 16.

A 2024 National Youth Tobacco Survey suggested that only 1.8% of middle and high school students in the U.S. use nicotine pouches. However, they were still the second-most commonly used tobacco product after e-cigarettes in this demographic.

Another study, published in the journal JAMA in 2024, found that sales of nicotine pouches in the U.S. had increased by 641% between 2019 and 2022 but that only 2.9% of adults ages 18 and up reported ever using them. This raised questions as to what other groups have been using and raising the demand for these products.

This article is for informational purposes only and is not meant to offer medical advice.

We've all seen it, typically on television or on stage: A hypnotist selects a few members from the audience, and with what seems to be little more than a steely stare or a few choice words, they're suddenly "under the spell." Depending on what the hypnotist suggests, the participants laugh, dance and perform without inhibition.

Or perhaps you've experienced hypnosis another way — with a trip to a hypnotherapist for a series of sessions to help you stop smoking, lose weight, manage pain or deal with depression. This is no longer unusual; thousands of Americans have done the same thing. And many were helped.

Hypnosis has been found to be effective for treating irritable bowel syndrome, and it may be beneficial for weight reduction, sleep disorders and anxiety. For mild to moderate depression in adults, hypnotherapy is as effective as cognitive behavioral therapy, and it can help with depression in children. Hypnosis is also used to treat phobias, PTSD and to control pain during surgery and dental procedures in both adults and children.

Yet despite the evidence, its widespread use and its growing popularity, hypnosis is still viewed with skepticism by some scientists, and with curiosity by much of the public. As a researcher studying altered states from a cognitive and neuroscientific perspective, I'm happy to help pull back the curtain to show you how hypnosis works.

A hypnotherapy session

In simple terms, hypnosis is a procedure that helps people imagine different experiences that feel very real. When that occurs, the person can be said to be in a state of hypnosis.

Little is known about what characterizes a hypnotic state in terms of brain activity, but neuroimaging studies indicate a decrease in activity in the parts of the brain responsible for self-referential thought and daydreaming, and increased links between the parts responsible for attention and action.

Related: Electric pulses to the brain may make people easier to hypnotize

These results are consistent with the idea that people who are hypnotized are in a state that inhibits internal thoughts and other distractions, such as bodily sensations or noises, that may interfere with the hypnosis.

A therapist's first set of suggestions typically includes the "hypnotic induction," which helps the subject increase their responsiveness to other suggestions. An induction may be like this: "I will now count from 5 to 1. At every count, you will feel even more relaxed, and that you are going deeper and deeper into hypnosis."

When responding to suggestions, the subject's experience feels involuntary. That is, it's happening to them, rather than generated by them. This is known as the classical suggestion effect. Following a suggestion to move their arm, the subject may feel as though their arm rises on its own, rather than being raised of their own volition.

For perceptual suggestions, the experience can feel quite real and distinct from voluntary imagination. If I ask you to imagine hearing a dog barking outside, it requires an effort, and the experience does not feel like there's really a dog barking outside. But through hypnotic suggestion, responsive subjects will feel like they hear a dog barking, and they won't be cognizant of any effort to make it happen.

What makes people hypnotizable?

You can't force anyone to be hypnotized. Willingness to participate, a positive attitude, motivation and expectation are hugely important. So is the ability to set aside the fact that the situation is imaginative. It's like when you become fully absorbed with the story and characters in a movie — so absorbed you forget you're in a theater.

Good rapport with the therapist is also critical. If you refuse to cooperate or decide hypnosis won't work, it won't. A good comparison may be meditation: You can listen to a meditation recording, but if you're unwilling to follow the instructions, or if you're unmotivated or distracted, it won't have any effect.

Few traits predict whether someone is easily hypnotizable, but people are not equal in their ability to respond to hypnotic suggestions. Some people vividly experience a wide array of suggestions; others, not nearly as much. There are indications that women respond slightly better to hypnotic suggestions than men, and that peak hypnotizability occurs during late childhood and early teenage years.

From a neuroscientific perspective, it appears that hypnotic suggestions do not act directly on our executive functions, but rather on our self-monitoring functions. That is, hypnosis does not directly decide our behaviors for us. Rather, it modifies how the brain monitors what it's doing. So when the hypnotist suggests that you raise your arm, you're still the one making that decision — although your experience may seem like the arm is moving by itself.

Exposure therapy, self-hypnosis

The aim of hypnotherapy is to induce changes in negative emotions, perceptions and actions. Suppose you are afraid of public speaking. Through suggestions, the therapist may make you go through the experience of talking in front of an audience. Again, it feels real — your stress level will rise, but ultimately you'll habituate yourself and learn to cope with the stress, even as the therapist suggests increasingly challenging scenarios.

Hypnosis can also be used as a preparation or replacement for exposure therapy, which is a method to treat phobias or anxiety related to specific situations by progressively exposing the patient to increasingly challenging situations. If you're afraid of birds, the therapist may suggest you imagine holding a feather; then imagine getting near a bird in a cage; then imagine going to the park and feeding pigeons. This is more effective, and feels more real, than mere visualization.

The hypnotherapist can also teach self-hypnosis techniques. Subjects can learn to induce a state of relaxation that's associated with a gesture, such as closing the left hand.

Hypnotic suggestions like this decrease anxiety by promoting activation of the parasympathetic nervous system, which stimulates bodily functions during times of rest, such as digestion and sexual arousal, and deactivates the sympathetic nervous system, which stimulates the fight-or-flight response.

Progress can occur after less than 10 sessions with some disorders, such as insomnia in children. But it may take longer for others, such as depression. And just as hypnosis is not suitable for everyone, it's also not suitable for everything.

What's more, not all hypnotherapy products on the market are backed by scientific evidence. It is safer to go to a hypnotherapist who's licensed in your state. You should ask whether they are affiliated with or certified by a professional association of hypnotherapists. You can then confirm their affiliation on the association's website. For instance, the American Society of Clinical Hypnosis allows you to search members by name.

Although Medicare does not cover hypnotherapy, some private insurance partially covers the costs for some conditions, provided the treatment is performed by a licensed clinical mental health professional. One session will typically cost between US$100 and $250.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

For young people who want to give up vaping, simple interventions — like hotlines, informational text messages and nicotine replacement — are helpful tools for quitting, a new study finds.

The research, published Wednesday (Dec. 11) in the American Journal of Preventive Medicine, explored these interventions to help 18- to 25-year-olds quit vaping, and it reported strikingly positive results.

Researchers at The Ohio State University (OSU) assigned the 508 young adults, who were all keen to give up vaping, to four treatment groups. These volunteers received various combinations of coaching over the phone, nicotine replacement therapy (NRT) and mobile health support via text messages and online informational content.

After three months, over 40% of the participants in each group had gone at least a week without vaping. Those who got two interventions — namely, phone calls and NRT — or all three interventions fared the best, with a 48% quit rate.

"Unfortunately or fortunately, we were very effective in producing cessation," said study co-author Liz Klein, chair of OSU's Division of Health Behavior and Health Promotion — fortunately, because it's normally difficult to help people to stop vaping, and unfortunately, because the uniformly high rates left questions about which was the most effective intervention tested.

"We have to really do more work to understand the various pieces," Klein told Live Science.

Related: Is vaping healthier than smoking?

The best ways to help people, especially teens and young adults, stop vaping remains uncertain. "A lot of folks assume that quitting vaping is going to be identical to quitting smoking, and we just don't have evidence that they're exchangeable," Klein said.

But the issue is gaining attention. In 2018, the U.S. Surgeon General declared e-cigarette use by teens and young adults to be an epidemic. Atop many unknowns about the potential long-term harms of vaping, Klein said nicotine addiction may change young people's brain development, potentially altering their ability to concentrate and their responses to other drugs of abuse.

For the new study, people who vaped but did not smoke cigarettes were recruited via social media. They all received coaching via telephone calls — commonly known as a quitline, which is an established support tool for people seeking to stop smoking. "Ethically, we didn't feel comfortable" including a control group who received no help, for comparison, Klein noted.

One group was given only these calls. A second group received NRT, too, and were sent nicotine patches and either gum or lozenges. The third group received quitline calls and support via text messages, which shared online videos and other informational content. A fourth and final group received calls, NRT and mobile support.

The quit rates were 41% for quitline calls only, 43% for calls plus mobile support, 48% for calls and NRT, and 48% for all three interventions.

The study therefore supports NRT as a vape-quitting aid, but it poses questions about mobile support. Although a previous trial found that text messages boosted quit rates, here, they seemed to add negligible benefits. "We need to drill down and understand a little bit more" why that might be, Klein said.

But the surprisingly high cessation seen across all of the groups suggests quitlines could help young adults kick vaping.

"This study is only the third randomized trial of a vaping cessation program for young people to be published," said Amanda Graham, chief health officer at the Truth Initiative, a charity dedicated to preventing nicotine addiction in young people, who was not involved in the study. It's exciting to see this neglected field growing, she added.

However, suggestive as the results are, Graham said that because the study lacked a control group without quitline support, it can't yet be concluded exactly how effective the phone coaching was. She would also like to see longer follow-up than the week of abstinence at the three-month mark used in this study.

Klein and her colleagues are now deciding which interventions to test in larger, longer trials, which will also look at people who both vape and smoke.

There was considerable demand to join this study, Klein said, and both she and Graham noted that, in recent large surveys, a majority of young people who vape say they want to stop. This contrasts with previous generations of young people who smoked cigarettes and often viewed quitting as something to do later in life.

"With traditional cigarette smoking, young people weren't beating down the door to say, 'I need services and I'm not getting them,'" Klein said. "I do think we're detecting a higher rate of interest and engagement."

This article is for informational purposes only and is not meant to offer medical advice.

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Using cannabis heavily and regularly may raise the risk of head and neck cancers, a new study finds.

The research looked at 20 years' worth of medical records from more than 116,000 U.S. adults with cannabis use disorder (CUD). Estimated to affect 3 in 10 cannabis users, the disorder is defined as problematic cannabis use that leads to significant impairment or distress and involves signs of tolerance — in which someone needs to use more of a drug to get the same high — and dependence, including withdrawal symptoms.

Compared to adults without CUD, these individuals were 3.5 to five times more likely to develop head and neck cancers, according to the new study, published Thursday (Aug. 8) in the journal JAMA Otolaryngology-Head & Neck Surgery. These include cancers of the mouth, throat, voice box, saliva glands and oropharynx, which encompasses the tongue, tonsils and back wall of the throat.

"This is one of the first studies — and the largest that we know of to date — to associate head and neck cancer with cannabis use," senior study author Dr. Niels Kokot, a head and neck surgeon at the University of Southern California Head and Neck Center, said in a statement. "The detection of this risk factor is important because head and neck cancer may be preventable once people know which behaviors increase their risk."

Related: Could cannabis treat cancer someday? Here's what the science says so far

The research pulled data collected between 2004 and 2024 from TriNetX, a trove of patient data from 64 U.S. health centers. In addition to the patients with CUD, the study included data from over 3.9 million people without a diagnosis of the disorder.

The people with CUD were directly compared with people of the same age and sex, and the researchers also accounted for alcohol and tobacco use, which are major drivers of head and neck cancers.

Compared with the control group, people with CUD were more likely to develop every type of head and neck cancer, except hypopharyngeal cancer, which affects the lower throat.

The study did not investigate how patients used cannabis — for instance, whether they smoked or took edibles. Thus, it can't say for sure whether it's the smoke that's driving the cancer, given that cannabis smoke contains some carcinogens that are similar to those in tobacco smoke. Alternatively, it could be that active components in cannabis, such as THC, activate certain enzymes that can fuel cancer.

"The cannabinoids themselves could be carcinogenic, and it could also be that the smoke itself has potential for carcinogenesis," Kokot told NBC News.

The study does have some limitations, however. For example, people's cannabis use was self-reported, and the exact doses they were exposed to are unknown.

While it's too soon to say if the link between heavy cannabis use and head and neck cancers holds up over time, "the implications of the report … are sobering," doctors from the UC San Diego Moores Cancer Center and Xiangya Hospital in China wrote in a commentary about the study.

It's worth noting that the study's data spanned two decades in which cannabis use became more commonplace, they wrote. If cannabis can be confirmed to fuel cancer in some way, we might expect that the rate of head and neck cancers linked to the drug will become more common in line with cannabis use, they concluded.

This article is for informational purposes only and is not meant to offer medical advice.

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To save a man who needed a double-lung transplant but had a very complicated case, doctors relied on three key tools: antibiotics, an artificial lung and DD-size breast implants.

"I never imagined we'd be using DD breast implants to help bridge a patient to lung transplantation, but our team is known for taking on the most difficult cases and thinking outside the box to save lives," Dr. Ankit Bharat, chief of thoracic surgery and director of the Canning Thoracic Institute at Northwestern Medicine, said in a statement.

The transplant patient, a 34-year-old Missouri man named David "Davey" Bauer, had started smoking cigarettes at age 21. He smoked about a pack a day until switching to e-cigarettes, or vape pens, in 2014. In April of this year, he began experiencing shortness of breath and was diagnosed with the flu. He also developed a bacterial infection of the lungs that was resistant to antibiotic treatment.

Bauer was admitted to a St. Louis hospital and was placed on an ECMO (extracorporeal membrane oxygenation) machine, which does the work of the heart and lungs, but his condition worsened. That's when Northwestern received a call about Bauer needing a double-lung transplant.

Related: Creating 'universal' transplant organs: New study moves us one step closer.

"Davey's lungs were so heavily infected that they started to liquify," Dr. Rade Tomic, a pulmonologist and medical director of the Northwestern Medicine Canning Thoracic Institute Lung Transplant Program, said in the statement. "If you looked at his X-ray, there was nothing left — the lungs were completely filled with pus."

The Northwestern team determined that, for Bauer to survive the transplant, his infection would need to clear first. To make that happen, they'd need to remove his extensively infected lungs.

To deliver oxygen to the man's organs while his lungs were removed, the team jerry-rigged pieces of an ECMO machine to create channels that would keep oxygenated blood flowing to Bauer's heart and out to the rest of his body.

"I spent the whole night thinking about how I'm going to create these channels and do all these things," Bharat told CNN. But even with these artificial channels in place, the medical team still needed a way to physically support Bauer's heart, given that the lungs, which normally surround it in the chest cavity, would be removed. In the end, they decided breast implants were the best tools for the job.

"One of our plastic surgeons was very gracious to give us a rapid-fire course on the different types, shapes and sizes of breast implants, so we picked out a couple options and some of them were easier than others to mold inside Davey's chest, with the DD option being the best fit," Bharat said in the Northwestern statement. 

Bauer's infected lungs were removed on May 26, his name came up for new lungs on May 27, and the procedure was completed on May 28. 

"I honestly barely remember walking into the ER [in St. Louis]," Bauer told People in an exclusive report published Nov. 7. "Then I woke up out here in Chicago with new lungs." 

Bauer was discharged to rehabilitation therapy in late September after recovering in the intensive care unit for several months.

"I plan to get a t-shirt made that says 'DD Davey' on it and change all my gaming profiles," Bauer said in the Northwestern statement. "But in all seriousness, I'm so proud to be the first Northwestern Medicine patient to undergo this innovative procedure, and I hope this medical first paves the way for more critically ill patients to receive lung transplants in the near future."

Bauer's GoFundMe page details more of his story.

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People with a history of heavy cigarette smoking should be checked regularly for lung cancer even if it's been many years since they quit, the American Cancer Society (ACS) now recommends.

This new recommendation, released Wednesday (Nov. 1) in CA: A Cancer Journal for Clinicians, is a departure from the ACS' previous advice, which said former smokers no longer needed annual screening once they went 15 years without smoking.

"Lung cancer is a disease of the elderly, and so, basically, your risk starts becoming greatest once you're in your 60s, which was probably during this time period when people were stopping to be screened," Dr. William Dahut, chief scientific officer for the ACS, told CNN.

"People developed a false sense of security," which may have contributed to the "abysmally low" rates of screening, Dahut added in an interview with NBC.

Related: Nicotine vapes are one of the best tools to help people quit smoking, review of 300 trials suggests

Rates of annual lung cancer screening vary among states, but the national average suggests that only about 10% of eligible people get checked, Robert Smith, senior vice president for early cancer detection science at the ACS and lead author of the guideline, told The Washington Post. Screening involves low-dose computed tomography (low-dose CT), a scan that combines a series of X-rays into a detailed image of the inside of the body.

The small percentage of people who do get screened often fail to get their next scan the following year, Smith said. "I don't think they fully appreciate it is not one-and-done."

In addition to eliminating the years-since-quitting clause, the ACS broadened its guidelines in several other important ways. It used to recommend annual screening to current and former smokers ages 55 to 74 who had at least a 30 "pack-year" smoking history and had quit less than 15 years ago. (Thirty pack-years is the equivalent of smoking one pack of cigarettes per day for 30 years, or two packs a day for 15 years, and so on.)

Now, the ACS recommends that current and former smokers ages 50 to 80 with a 20 pack-year smoking history be screened annually, regardless of whether or when they quit. These changes mean that about 19.3 million people in the U.S. should now be eligible for screening, compared with 14.3 million under the previous guidelines, NBC reported.

The ACS' new guidelines mostly align with recommendations from the U.S. Preventive Services Task Force (USPSTF), a panel of volunteer experts in primary care and prevention. The USPSTF recommends yearly screening to adults 50 to 80 years old with a 20 pack-year smoking history, but it still says people can stop getting screened if it's been more than 15 years since they quit.

"The new guidelines from the American Cancer Society, I think, are reflective of newer modeling evidence," Dr. Matthew Triplette, a pulmonologist and cancer prevention researcher at the Fred Hutchinson Cancer Center in Seattle who wasn't involved with either set of guidelines, told CNN. 

The new evidence suggests that the risk of lung cancer continues to rise as people age, even among those who have quit smoking for 15 or more years.

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Nicotine e-cigarettes are among the best tools to help people quit smoking.

That's according to an analysis of more than 300 clinical trials that collectively included more than 150,000 adult smokers worldwide. The data suggest that nicotine-containing e-cigarettes, or vapes — handheld devices that deliver nicotine via an aerosol with flavoring — and two pills called varenicline and cytisine were associated with the greatest chance of quitting smoking for at least six months. 

These stop-smoking aids' success rates were closely followed by those of dual nicotine replacement therapy (NRT), an approach that involves using two aids at the same time, such as a nicotine patch alongside taking gum or lozenges. However, the evidence for dual NRT was less certain than that for vapes and the medications. 

The authors of the new review, published Tuesday (Sep. 12) in the Cochrane Database of Systematic Reviews, hope the findings will provide more clarity on the relative effectiveness of these stop-smoking aids. 

"Our findings provide clear evidence of the effectiveness of nicotine e-cigarettes and combination nicotine replacement therapies to help people quit smoking," Jamie Hartmann-Boyce, senior study author and assistant professor at the University of Massachusetts Amherst, said in a statement. 

Related: Is vaping healthier than smoking?

"The evidence also is clear on the benefits of medicines, cytisine and varenicline, but these may be harder for some people to access at the moment," he said.

Varenicline, although currently available in the U.S., is not accessible in many countries worldwide due to recent shortages. Meanwhile, cytisine is not widely available because it's been licensed in only some countries in eastern and central Europe and western Asia, and in Canada. That said, the drug is in late-stage clinical trials in the U.S. and thus moving toward approval.

"We're in a kind of weird position with this review where we're saying these are the top three most successful, but actually only one of them is widely available at the minute and that's e-cigarettes," Nicola Lindson, lead study author and a senior researcher and lecturer at the University of Oxford, told Live Science.

The review revealed that, on average, 14 in 100 people who are trying to quit smoking are likely to succeed for at least six months using e-cigarettes, varenicline or cytisine. That's compared to 12 in 100 who use dual NRT, 9 in 100 who use one form of NRT, and 6 in 100 who don't use any stop-smoking aids. 

In the paper, the authors highlighted the need for further data to determine the long-term consequences of using these aids, beyond the six-to-12-month timeframe that most of the trials they analyzed considered. Lindson added that, in the future, more trials could directly compare the effectiveness of these different treatments, for example, by pitting cytisine against e-cigarettes in addition to a placebo, or could potentially test the use of multiple treatments together.

The rising popularity of e-cigarettes has raised concerns about their potential environmental impact and their use by young people who have never smoked. Given that vapes are a relatively new stop-smoking aid — developed in 2003, compared to NRT, which has been approved in the U.S. since the 1980s — scientists are still researching their potential health effects. 

According to Lindson, though, the message for people trying to stop smoking is clear.

"What we would always recommend is that people should be encouraged to use e-cigarettes to stop smoking if they've already smoked," she told Live Science. "But it's best not to use them if you have never smoked, because they're not going to be completely risk-free — they're just, we believe, a lot safer than smoking." 

This article is for informational purposes only and is not meant to offer medical advice.

Night owls' tendency to smoke more cigarettes and drink more alcohol than early birds could explain why evening people have a higher risk of early death than early risers do, a large analysis suggests.

"This can reassure people concerned about what being a morning or evening person means for their life expectancy and health," study co-author Jaakko Kaprio, a professor of genetic epidemiology at the University of Helsinki in Finland, told Live Science. "It's not about the chronotype [being a morning or evening person] itself that is dangerous, but it is the associated lifestyle factors." 

Other scientists previously found elevated mortality rates among night owls compared with morning people, but these past analyses didn't account for differences in participants' alcohol consumption or smoking quantity, making it difficult to tell whether being an evening person directly increases mortality risk.

Now, Kaprio and his colleagues have analyzed health and lifestyle data from more than 23,000 people living in Finland to tease out whether being a night owl directly affects the risk of dying within the next few decades. The findings were published Friday (June 16) in the journal Chronobiology International.

Related: Life really is harder for night owls. Here's why. 

In a survey carried out in 1981, participants — who were 41 years old at the time, on average — self-reported their smoking and drinking habits. On a questionnaire, they also stated whether they were "clearly a morning person," "to some extent a morning person," "clearly an evening person" or "to some extent an evening person." 

Overall, more than 8,700 participants died during the 37-year follow-up period, which ended in 2018. By analyzing participants' health records collected in that time, the researchers found that participants who initially said they were "clearly" evening people had a 21% higher risk of death from any cause compared with those who were "clearly" morning people.

This initial analysis only adjusted for participants' ages and sex, but the scientists then ran a second analysis that accounted for additional factors that could affect people's mortality risk, such as body mass index (BMI), self-reported sleep duration, educational level, rates of chronic diseases, alcohol consumption and smoking status and quantity. After the researchers controlled for these additional factors, the night owls' overall excess mortality risk dropped to just 9%.

Why did night owls' risk fall by more than half? The team found that most of their raised mortality risk was attributable to higher alcohol consumption and heavier smoking among evening people than in morning people. Supporting this idea, they found that mortality rates did not differ between evening and morning people who were light drinkers that never smoked. 

What's more, an analysis that accounted for differences in age and sex found that rates of death due to alcohol-related diseases and accidental alcohol poisoning were 92% higher among "clearly" evening people compared with "clearly" morning people. And deaths due to lung and airway cancers, made more likely by smoking, were 78% higher among night owls. Both of these risks fell "substantially" when other lifestyle factors, including alcohol and smoking habits, were considered. These findings further support the idea that smoking and drinking, not staying up late, raise night owls' risk of death, the authors concluded. 

The remaining 9% increase in mortality rate among evening people is unlikely to be directly due to their late bedtimes, Kaprio said. 

"We measured people's chronotype and alcohol consumption at one time using one question, which means we don't account for how things might have changed years later," he said. "If we measured alcohol and drinking habits perfectly throughout the study period, I think the raised risk may be much less or absent." 

Kristen Knutson, a professor of neurology at Northwestern University who was not involved in the study, agreed that the remaining 9% risk isn't necessarily linked to chronotype.The risk could be related to yet-unknown "unmeasured environmental or behavioral factors, rather than an inherent risk associated with a later internal clock," she told Live Science. 

It remains unclear why being an evening person is linked to heavier smoking and drinking, Kaprio said. Beyond potential differences in the social activities of evening and morning people, "one explanation would be that there are genes that predispose you to both being an evening person and also to drinking more alcohol," he said. 

Electronic nicotine delivery systems (ENDs), also known as electronic cigarettes, e-cigarettes or vape pens, were introduced in the early 2000s as an alternative to tobacco products. Instead of generating smoke, these pocket-sized devices deliver nicotine with an aerosol that looks like water vapor. But are vape pens "'healthier"' than cigarettes?

It depends. Experts told Live Science that they agree that "vaping" poses a small fraction of the risks of smoking. However, they stress that vape pens are not entirely safe, and we still do not know enough about the long-term effects of e-cigarette use. 

It took decades of research to prove the harms of cigarettes — after being introduced to the U.S. in the early 19th century, cigarettes were first linked to lung cancer and other diseases in the 1940s and 1950s. Vape pens have been on the market for less than 20 years, and complicating the situation, some vape liquids and types of ENDs may be more harmful than others. 

So how harmful are e-cigarettes? Here is everything we know so far about the potential health effects of vaping.

Smoking vs. vaping: Which is more toxic?

Cigarettes contain tobacco leaves and other additives, such as flavorings and preservatives, that, when burned, generate up to 7,000 different chemicals, including hydrogen cyanide, arsenic, lead and carbon monoxide, according to the American Cancer Society (ACS). 

Dozens of these harmful chemicals are carcinogens, or cancer-causing substances, most of which come from the tobacco leaves themselves, rather than the additives, according to the ACS. Smoking cigarettes can increase the risk of several different types of cancer, as well as cause lung and heart disease. By contrast, nicotine, the addictive chemical in tobacco leaves, does not cause cancer, according to the WHO; that said nicotine can have other harmful effects on the body, in addition to being highly addictive.

Vape pens come in many shapes and sizes, but they all work based on the same principle: A battery-powered core heats and then rapidly cools a vape liquid, also called e-liquid or vape juice, creating a smoke-free aerosol that a user inhales, or "vapes." Vape juice can contain nicotine that's either synthetic or derived from tobacco, but it doesn't contain tobacco leaves or other chemicals found in the plant.

Given both the lack of smoke and the lack of tobacco in e-cigarettes, people who completely switch from smoking to vaping tend to have lower exposure to toxic substances than do individuals who use cigarettes, Dr. Alayna Tackett, an assistant professor in the Division of Medical Oncology and the Center for Tobacco Research at the Ohio State University Wexner Medical Center, told Live Science by email. 

However, vape pen liquids can contain other substances that may form carcinogenic compounds when heated, she said.

How toxic is vape liquid?

Most e-liquids consist primarily of nicotine, flavorings and solvents, which generate vapor and keep ingredients in suspension. However, the exact composition of a specific e-liquid will largely depend on the brand's manufacturing process, according to a 2021 review published in the journal Pharmacology & Therapeutics. This makes it difficult to assess exactly how toxic e-liquids are. 

The two most common solvents used in e-liquids are propylene glycol and glycerol, which the Food and Drug Administration (FDA) generally recognizes as safe for human consumption. However, they may not be safe to inhale, the 2021 review states. Propylene glycol and glycerol are both airway irritants, meaning they may cause inflammation and other adverse reactions in the respiratory system, the review authors wrote. 

Similarly, while flavorings used in e-liquids are generally safe to eat, no studies show they are safe to inhale as aerosols, and some may be dangerous to inhale, according to the review. For example, the buttery-flavored compound diacetyl was linked to a severe respiratory disease called bronchiolitis obliterans — a condition nicknamed "popcorn lung" because workers at a microwave popcorn factory developed the disease after inhaling diacetyl.

Both solvents and flavoring agents may generate toxic byproducts, such as formaldehyde, a substance classified as a probable human carcinogen, the review authors wrote. Inhaling formaldehyde in high doses can be harmful, and a 2017 study in the journal PLOS One found that concentrations of formaldehyde from heated vape liquid solvents may exceed acceptable limits established by the U.S. Environmental Protection Agency. In theory, this may put ENDS users at a higher risk of cancer, but this cancer risk has not been clearly demonstrated in research. 

As noted previously, most e-liquids also have varying levels of nicotine. Because tobacco smoke has a relatively low nicotine concentration and is harsh on the lungs, it is difficult to overdose on the addictive chemical when smoking cigarettes. Vape pens, however, can contain high concentrations of nicotine, and users can often dial up the amount of nicotine delivered in a single puff. 

As a result, vaping may increase the risk of nicotine overdose, the review authors noted. Nicotine overdose, or nicotine poisoning, is a condition whose symptoms include muscle twitching, fainting, vomiting, heart palpitations, seizures and difficulty breathing. If it triggers severe enough symptoms, nicotine poisoning can sometimes be deadly, according to Mount Sinai.

A 2014 study by the CDC revealed a significant uptick in nicotine vape pen-related calls to poison control centers — the number of calls increased from one per month in September 2010 to 215 per month in February 2014, while the number of calls involving cigarettes remained steady over that time.

Can vape liquid get contaminated?

Vape pens themselves can also contaminate e-liquids. Repetitive heating of the device's core can cause nickel, copper, iron and other metals to slip into the aerosol; breathing in such metals could lead to an increased risk of cancer, kidney damage, heart disease and neurological disorders, according to the Pharmacology & Therapeutics review.

The risk of metal contamination may be higher for closed pod ENDs, which have replaceable e-liquid cartridges, than in disposable vape pens designed to be used for a while and then tossed. And the metal contamination from a pod type e-cigarette may change across its lifetime, according to a 2023 study in the journal Toxics. Researchers found that the longer the device was used, the higher were the concentrations of hazardous metals in its vapor.

In addition, black-market vaping products containing THC (the psychoactive ingredient in marijuana) have sometimes been contaminated with vitamin E acetate, a synthetic form of vitamin E. Likely introduced by manufacturers as a way to dilute the THC content of vape juice, vitamin E acetate was linked to a major outbreak of vaping-related illness that hit the U.S. in 2019.

What diseases have been linked to e-cigarettes?

People who smoke cigarettes would be better off switching to e-cigarettes if they are still using nicotine and haven't had success with other substitutes, like nicotine gum. However, for those who have never smoked, it remains unclear what the health implications might be from vaping. 

The evidence is limited and we do not have studies showing the long term impact of vaping, Hazel Cheeseman, deputy chief executive of Action on Smoking and Health, a charity set up by the Royal College of Physicians in the U.K. to promote smoking abstinence, told Live Science by email. 

That said, preliminary research suggests that vaping may raise the risk of certain health conditions.

Lung injury and lung disease

E-cigarettes may lead to irreversible lung damage and lung disease, according to the American Lung Association. 

For example, vaping can sometimes cause E-cigarette- or Vaping Product-Associated Lung Injury (EVALI), according to a 2020 review published by The American Journal of Medicine. Symptoms of EVALI include shortness of breath, cough, chest pain, nausea, abdominal pain, fever and chills. Up to one-third of patients admitted to an intensive care unit with the condition require mechanical ventilation, the review authors noted. The cause of EVALI is not fully understood, though it appears that vitamin E acetate plays a central role. However, other compounds found in both nicotine- and THC-containing vape liquids may also contribute to the condition, according to Yale Medicine.

In addition, e-cigarette use has been linked to lung diseases, including pneumonia, respiratory bronchiolitis-associated interstitial lung disease (an inflammatory disease previously seen mainly in heavy tobacco smokers), and hypersensitivity pneumonitis (a type of allergic reaction in the lungs), according to a 2022 review published in the journal Annual Review of Physiology.

Vape pen use may also weaken the lungs' immune defenses and increase the risk of infections with pathogens, including the influenza virus and Streptococcus pneumoniae bacteria, according to a 2022 review published in the journal Cureus.

Lastly, studies suggest that e-cigarettes may aggravate symptoms of asthma in adolescents with the condition, according to a 2023 review published in the journal Current Opinion in Allergy and Clinical Immunology. However, more research is needed to understand this effect.

Eye disorders

Exposure to e-cigarette vapor may also lead to eye disorders, according to a 2021 review published in the journal International Ophthalmology. Studies suggest that e-liquid substances such as aldehydes and flavorings may damage the eyes' tear film and lead to inflammation, worsening of the sight and reduced blood flow to the eye, according to the article. However, more research is needed to understand what exactly is causing these effects. 

Scientists are getting closer to understanding the link between e-cigarette use and eye disorders. For example, a 2021 mice study published in the Journal of Molecular Medicine found that full-body exposure to vape vapor may prompt the immune system to release more cytokines - chemical messengers that induce inflammation - which then accumulate in the superficial parts of the eye responsible for light absorption, as well as nourishment and protection of the deeper eye tissues. Animals exposed to e-cigarettes had a particularly high level of cytokines interleukin 1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α), compounds that may damage the delicate barrier that regulates the transport of nutrients between the eye and the bloodstream, the study authors wrote.

Tooth decay

Very little research has been done on the impact of vaping on oral health. However, preliminary evidence suggests that people who vape are more at risk of developing cavities than those who do not vape or smoke, Dr. Sam Jethwa, the vice president of The British Academy of Cosmetic Dentistry, told Live Science by email. 

When people inhale during vaping, the sugar in some vaping liquid sticks to the teeth, causing damage to the tooth enamel. Vape liquid may also change the microbiome of the mouth, making it more hospitable to decay-causing bacteria, Jethwa told Live Science. Vaping also appears to encourage tooth decay in areas where it usually does not occur, such as the bottom edges of front teeth rather than the deep grooves of the back teeth, he said. 

Vaping can also decrease saliva production and cause dry mouth, which is a known driver of cavities. "Saliva provides a natural lubrication for the mouth and helps to neutralize the acid that can decay tooth enamel," Jethwa said.

DNA damage and cancer

We have not seen any evidence to date that vaping contributes to cancer, Dr. Irem Patel, consultant integrated respiratory physician and honorary senior lecturer at King's College London In England, told Live Science by email. However, it can take decades of follow-up and complex study designs for such increased risk to show up in the data. 

A first-of-its-kind study published in 2023 in the journal Nicotine & Tobacco Research compared the extent of DNA damage in the cells that line the inside of the mouth between vape pen users who never smoked cigarettes, cigarette smokers who did not vape, and non-users. Researchers found that people who vape and those who smoke cigarettes may show similar levels of DNA damage, and such DNA changes can be a precursor to cancer. Sweet, mint and menthol flavored e-liquids appeared to inflict the most damage, the study found. Still, more research is needed to understand this correlation.

Daily cigarette smoking reduces the size of your brain, a new study of more than 28,000 people suggests.

Scientists have previously found that people who smoke tend to have smaller brains compared to non-smokers, in terms of volume, but it was unclear whether smoking causes the brain to shrink or if people with smaller brains are more likely to start smoking. Now, researchers provide strong evidence that smoking causally shrinks the brain in a new report, which was posted April 28 on the preprint database medRxiv and has yet to be peer-reviewed.

"This is a very important study," Dajiang Liu, who studies the genetics of smoking risk at the Penn State College of Medicine and was not involved in the study, told Live Science in an email. "The work is rigorously conducted and the result is important from a public health perspective."

The scientists analyzed brain imaging data from the U.K. Biobank, a massive repository of genetic and health data from U.K.-based participants. In addition to brain scans, the team analyzed participants' self-reported smoking habits, as collected in surveys. Participants took these surveys twice, once between 2006 to 2010 and again between 2012 and 2013. In the second time window, participants' brains were also imaged using a method called magnetic resonance imaging (MRI).

Related: Quitting smoking by age 35 brings your risk of death in line with 'never smokers'

The scientists found that, compared to people who'd never smoked daily, participants who smoked on a daily basis at some point prior to having their brains imaged had brain volumes that were 0.4 cubic inches (7.1 cubic centimeters) smaller, on average. 

This difference in brain volume included a 0.3 cubic inch (5.5 cc) decrease in the gray matter of the brain, which contains the bulky bodies of brain cells, or neurons. Smoking daily at some point in the past was also linked to a 0.1 cubic inch (1.6 cc) decrease in the white matter of the brain, which includes the long insulated wires that connect neurons to each other.

Next, the researchers found that, among the past daily smokers, participants who smoked more heavily showed even larger differences in gray matter volume. Each additional "pack year" smoked — a measure equivalent to smoking one pack a day for one year — was linked to a roughly 0.01-cubic-inch (0.15 cc) decrease in gray matter volume, on average. This "dose-response" relationship supports the idea that smoking causally reduces brain volumes, wrote the researchers in their paper. 

In contrast, how heavily people smoked did not significantly impact their white matter volume.

Further analyses revealed that people who had quit smoking for longer had slightly more gray matter in their brains, compared with those who quit more recently. This suggests that stopping smoking can slightly reverse the decline in brain volume. For example, quitting smoking an extra year earlier was linked to a further 0.005 cubic inch (0.09 cc) increase in gray matter volume among the past daily smokers.

The scientists also examined participants' genetic data to see if gene variants that influence smoking risk might be linked to differences in gray matter volume. They found that people with a higher genetic risk were more likely to have smoked in the past, but their genetics, in isolation, were not linked to gray matter volume. Instead, a history of daily smoking was strongly tied to gray matter volume, supporting the idea that smoking drives the changes.    

As brain shrinkage has been associated with neurological diseases, such as Alzheimer’s disease, establishing a causal link between smoking and brain volume decline furthers our understanding of whether smoking directly drives these diseases through this mechanism, wrote Liu. Further experiments will help to confirm the causal relationship between smoking and brain size, and the effectiveness of drugs that could potentially help prevent brain tissue loss, he added.

Cigarette smokers who quit before age 35 have similar death rates within a given time period to those who have never smoked at all, a large study suggests. 

Those who stopped smoking at later ages still saw substantial benefits, the research found, but their death rates exceeded those who quit before they reached 35 years old. For example, former smokers who quit between ages 35 and 44 showed a 21% higher rate of death from any cause, compared with "never smokers." And those who quit between ages 45 and 54 showed a 47% higher all-cause mortality rate than never smokers. 

"Among men and women from diverse racial and ethnic groups, current smoking was associated with at least twice the all-cause mortality rate of never smoking," the study authors wrote in a new report, published Monday (Oct. 24) in the journal JAMA Network Open. "Quitting smoking, particularly at younger ages, was associated with substantial reductions in the relative excess mortality associated with continued smoking."

This is the third large study to suggest that age 35 might be the optimal age to quit by, particularly for those who start smoking young, John P. Pierce, a professor emeritus in the Department of Family Medicine and Public Health at University of California, San Diego, wrote in a commentary of the study.

"It has been known for a long time that the earlier a smoker quits, the better," wrote Pierce, who was not involved in the new research. "However, it is now possible to be more specific with respect to the age that a smoker quits." 

Related: How drug addiction hijacks the brain 

The new study used data from the U.S. National Health Interview Survey, a questionnaire-based survey used to monitor the health of the U.S. population, and the National Death Index, a database of the nation's death records. The analysis included survey data from more than 550,000 adults who completed questionnaires between January 1997 and December 2018 and were between 25 and 84 years old at the time of recruitment. These included current smokers, former smokers and so-called never smokers, meaning people who smoked fewer than 100 cigarettes in their lifetimes. 

According to the National Death Index, nearly 75,000 of these study subjects had died by the end of 2019. Compared with never smokers, current smokers showed a significantly higher all-cause death rate, overall, as well as higher rates of death from cancer, heart disease and lung disease, specifically. 

Non-Hispanic white smokers showed the highest all-cause mortality rate, which was three times higher than that of never smokers. Non-white smokers, incliuding both Hispanic and non-Hispanic people, had slightly lower mortality rates, about twice that of never smokers. This may be related to the fact that these participants reported smoking fewer cigarettes per day, on average; starting to smoke at older ages; and being less likely to smoke daily, compared with white subjects.

"These results remind us that reducing smoking intensity (cigarettes per day) should be one of the goals for tobacco control programs," Price wrote in his commentary.

Crucially, while current smoking was linked to a higher risk of death across all racial and ethnic groups surveyed, "quitting smoking was associated with substantially reversed risks for all groups," the study authors wrote. 

In particular, those who quit by age 45 cut their excess risk of death by up to 90%, and those who quit before age 35 showed death rates very close to those of never smokers. Similarly, the study also found that, the more time had passed since a person quit smoking, the closer their mortality rate was to that of a never smoker. 

Having an age 35 deadline could be potentially motivating for young smokers working toward quitting, Price wrote in his commentary. "Without a proximal goal, it is tempting for smokers to abandon a quit attempt with cognitions such as 'I don't really need to do it just now.' The study … provides needed data to set a motivating proximate goal of quitting smoking before age 35 years," he wrote. But of course, all is not lost after age 35 — as the study suggests, quitting at older ages still reduces one's risk of death, just not as dramatically. 

The research does have some limitations. For instance, the information on subjects' smoking habits was gathered at one point in time, so some subjects may have quit or started smoking after being surveyed. "Thus, both the true hazards of smoking and the true benefits of quitting may be underestimated in this study," the authors cautioned. 

Nonetheless, the study still suggests that quitting smoking greatly reduces the risk of early death — especially if you do it young.

Tobacco is an incredibly addictive substance. Studies have found that smoking tobacco can be as addictive as heroin and cocaine, but what makes people crave a cigarette? And why do many people struggle to stop smoking despite being aware of the dangers?

The answer, it turns out, has to do with tobacco changing the way our brains work, making us want more of it, according to the U.S. Food and Drug Administration (FDA).

"Addiction is primarily defined as a loss of control on the use of a substance and continued use despite the consequences," Bernard Le Foll, Chair of Addiction Psychiatry within the Department of Psychiatry at the University of Toronto, told Live Science in an email. 

"Once an addiction to a substance is developed, people will experience cravings and/or withdrawal when not using it for a certain period of time. Tobacco is addictive because it contains nicotine, a psychoactive substance with high addictive potential," Le Foll said.

Related: How does cannabis get you high?

A psychoactive substance is one that impacts how the brain works and, according to the National Cancer Institute (NCI), "causes changes in mood, awareness, thoughts, feelings, or behavior." Other examples of psychoactive substances include LSD, alcohol and caffeine.

Nicotine is especially addictive when smoked or otherwise taken into the lungs because "the onset of the stimulant-like effects occurs very rapidly through this route of administration," David Ledgerwood, a clinical psychologist in the Substance Abuse Research Division at Wayne State University in Detroit, Michigan, told Live Science in an email.

While the initial "hit" of enjoyment from smoking a cigarette is felt almost immediately, it also disappears rapidly, which, according to Ledgerwood, leads smokers to consume tobacco products frequently in a bid to achieve "the same stimulant experience."

When tobacco is consumed, nicotine levels in the bloodstream spike and enter the brain. Once in the cerebrum, nicotine attaches to and activates receptors that release the "happy" brain chemical dopamine, which makes people feel good, according to the Mayo Clinic. As a result, smokers' brains quickly come to consider nicotine as a "feel-good" substance, and will crave it in the gaps between cigarettes.

Chronic smoking increases the number of nicotine receptors in the brain, which explains why addicted smokers have "billions more of these receptors than nonsmokers do," the Mayo Clinic reported.

If someone smokes regularly for months and years, their brain will become used to having nicotine to the point where, eventually, "they need nicotine to function well," Ledgerwood said. During periods when the addicted individual does not smoke, they may experience physical withdrawal symptoms until their brain can adjust to the nicotine's absence. Such symptoms include an inability to concentrate, insomnia, depression and lack of appetite, according to the NCI. 

This, among other factors, explains why so many smokers struggle to give up the habit, Ledgerwood said.

"Add to this physiological effect that cigarettes are legal, available at any gas station or corner store, and can still be smoked in many different locations, it becomes incredibly difficult for someone who wishes to stop smoking to do so," Ledgerwood added.

People who begin using tobacco products as children or teenagers may find it especially difficult to quit, as nicotine exposure can disrupt brain development, according to the FDA. And it's easy for young smokers to get hooked; brain imaging studies have shown that while reward systems in the brain mature early, the control center in the prefrontal cortex matures slowly, according to a 2012 report published originally in Cold Spring Harbor Perspectives in Medicine. "Compared with adults, adolescents are generally more motivated by rewards, are less averse to risks, and are more easily influenced by peers," according to the report.

Are some people addiction-prone?

But are some people more prone to addiction than others? Does everyone face similar difficulties when it comes to giving up smoking, or do some find it relatively easy to go cold turkey?

"I don't believe people are immune to addiction," Ledgerwood said. "Some people may be more prone to developing addictions than others, and it certainly appears to be the case that being exposed to addictive substances at an earlier age puts one at greater risk of developing an addiction."

The Fagerström Test for Nicotine Dependence, developed in 1978 by Swedish psychologist Karl-Olov Fagerström, is a questionnaire used to determine an individual's level of nicotine dependence related to cigarette smoking. The test has gone through several iterations since its introduction, but it remains in use to this day, and is still one of the main ways of assessing addiction. Questions in the test include asking when an individual smokes their first cigarette of the day, how many cigarettes they smoke each day, and whether they would smoke even if they were so ill as to be confined to their bed.

When someone scores particularly highly on this test, Ledgerwood explained, it is likely due to more than simply the body desiring frequent hits of nicotine. "For many people who smoke, there are powerful factors that contribute to their smoking," Ledgerwood said. "These individuals often grow up in homes where parents smoke, and the behavior has been modeled for them. 

"Cigarettes are still easily available in many places, and although there are restrictions on where people can smoke, there are still many opportunities for people to smoke in public. There are also still many depictions of smoking in popular culture (movies, TV shows) that may contribute to a sense that smoking is a normal, and possibly even glamorous, behavior," he added.

Moreover, studies have revealed that genetic factors play a role in nicotine dependence, meaning that addiction can run in families, according to a 2010 review in the journal Current Cardiovascular Risk Reports. The Mayo Clinic states that genetics "​​may influence how receptors on the surface of your brain's nerve cells respond to high doses of nicotine delivered by cigarettes," which could mean that, due to genetic inheritance, once people start smoking, some are more likely than others to subsequently continue the habit. According to 2008 research carried out by the American Psychological Association, "at least half of a person's susceptibility to drug addiction can be linked to genetic factors."

Despite the many risks associated with smoking, and though it is thought to contribute to the deaths of 8 million people worldwide every year — including 1.2 million who die from exposure to second-hand smoke — tobacco remains widely available and easily accessible.

However, while addiction occurs quickly, so do the health benefits once a person quits. According to the Mayo Clinic, within 20 minutes of smoking a cigarette, heart rate decreases; within 12 hours, levels of the toxic gas carbon monoxide return to normal in the blood; within three months, lung function and circulation improves; and after a year, the risk of a heart attack falls by half.

Originally published on Live Science.

Scientists have discovered a brand-new type of cell hiding inside the delicate, branching passageways of human lungs. The newfound cells play a vital role in keeping the respiratory system functioning properly and could even inspire new treatments to reverse the effects of certain smoking-related diseases, according to a new study. 

The cells, known as respiratory airway secretory (RAS) cells, are found in tiny, branching passages known as bronchioles, which are tipped with alveoli, the teensy air sacs that exchange oxygen and carbon dioxide with the bloodstream. The new RAS cells are similar to stem cells — "blank canvas" cells that can differentiate into any other type of cell in the body — and are capable of repairing damaged alveoli cells and transforming into new ones. 

Researchers discovered the RAS cells after becoming increasingly frustrated by the limitations of relying on the lungs of mice as models for the human respiratory system. However, because of certain differences between the two, scientists have struggled to fill some knowledge gaps about human lungs. To get a better understanding of these differences on a cellular level, the team took lung tissue samples from healthy human donors and analyzed the genes within individual cells, which revealed the previously unknown RAS cells.

"It has been known for some time that the airways of the human lung are different than in the mouse," senior author Edward Morrisey, a professor at the Perelman School of Medicine at the University of Pennsylvania who specializes in respiratory systems, told Live Science. "But emerging technologies have only recently allowed us to sample and identify unique cell types."

Related: 10 strangest medical cases of 2021 

The team also found RAS cells in ferrets, whose respiratory systems are more similar to humans' than those of mice are. As a result, the researchers suspect that most mammals equal or larger in size are likely to have RAS cells in their lungs, Morrisey said.

RAS cells serve two main functions in the lungs. First, they secrete molecules that  maintain the fluid lining along bronchioles, helping to prevent the tiny airways from collapsing and maximizing the efficiency of the lungs. Second, they can act as progenitor cells for alveolar type 2 (AT2) cells, a special type of alveoli that secrete a chemical that is used in part to repair other damaged alveoli. (A progenitor cell is a cell that has the capacity to differentiate into another type of cell, similar to how stem cells differentiate into other cells.) 

"RAS cells are what we've termed facultative progenitors," Morrisey said, "which means they act as both progenitor cells and also have important functional roles in maintaining airway health." This means RAS cells play a vital role in maintaining healthy lungs, he added.

The researchers think RAS cells may play a key role in smoking-related diseases, such as chronic obstructive pulmonary disease (COPD). COPD is the result of inflammation of airway passages inside the lungs, which can be caused by smoking and, occasionally, air pollution, according to the Mayo Clinic. The inflammation of the airways makes it harder for the lungs to properly take in enough oxygen; as a result, COPD has similar symptoms to asthma. COPD can also lead to emphysema, in which alveoli are permanently destroyed, and chronic bronchitis, a long-lasting and intense cough usually accompanied by excess phlegm. Every year, more than 3 million people around the world die from COPD, according to the World Health Organization.

In theory, RAS cells should prevent, or at least alleviate, the effects of COPD by repairing damaged alveoli. However, the researchers suspect that smoking can damage, or even completely destroy, the new cells, leading to the onset of diseases such as COPD.

Patients who have COPD are often prescribed anti-inflammatory drugs or oxygen therapy to ease their symptoms. However, these are only temporary solutions and do nothing to reverse lung damage. RAS cells could potentially be used to improve treatments or even cure COPD, if researchers can properly harness these cells' regenerative properties.

"We really don't know if this discovery could lead to a potential cure for COPD yet," Morrisey said. "However, since COPD is a disease we know very little about, any new insight should help the field start to think about new therapeutic approaches that could lead to better treatments."

The study was published online March 30 in the journal Nature.

Originally published on Live Science.

Charred seeds found in the Utah desert represent the earliest-known human use of tobacco, evidence that some of the first people to arrive in the Americas used the plant, according to new research. The discovery reveals that humans used tobacco nearly 10,000 years earlier than previously thought, the researchers said.

Of all the intoxicant plants that humans use and abuse, tobacco has arguably had the most critical social and economic impact, the scientists of the new study said. It often played sacred, ceremonial or medical roles among the ancient Maya and other Indigenous American groups, and it helped drive the American colonial economy and thus Western expansion across the New World.

In addition to smoking, chewing and snuffing, people have used tobacco in a variety of different ways over the centuries. For example, ancient Maya rituals may have at times used intoxicating enemas of tobacco-laced fluids, and 18th-century English doctors gave drowning victims enemas of tobacco smoke in attempts to save their lives.

Until now, the earliest known evidence of human tobacco use was nicotine found in smoking pipes in Alabama that dated back about 3,300 years, according to research published in 2018 in the Journal of Archaeological Science: Reports. Now, scientists have unearthed signs that people used tobacco about 9,000 years earlier than previously thought.

Related: 10 things we learned about the first Americans in 2018

In the new study, archaeologists excavated the remains of a hunter-gatherer camp on mud flats in the Great Salt Lake Desert in Utah. Wind helped expose the site over time, said study lead author Daron Duke, an archaeologist with the Far Western Anthropological Research Group in Henderson, Nevada.

The scientists identified an intact ancient fireplace surrounded by stone artifacts, such as spear tips commonly used to hunt large game. The hearth also contained more than 2,000 bones and bone fragments, mostly belonging to ducks, which cut marks and other evidence suggested the people there cooked and ate.

The fireplace held pieces of charred willow wood that was probably the best firewood option in the region, as it commonly is now in modern nearby areas. The researchers then analyzed the wood with carbon dating, which involves measuring the amount of a radioactive form of carbon with a known rate of decay; the results suggested this wood was about 12,300 years old.

Within the fireplace, the scientists found the remains of four charred tobacco seeds. "The tobacco seeds were an unanticipated surprise," Duke told Live Science.

Although the researchers cannot say for sure how people at this site used tobacco, they said the seeds hinted at the presence of nicotine-loaded tobacco leaves and flowering stems. Perhaps the people there chewed or smoked tobacco by the fireside, the team said.

The scientists noted that others might argue the tobacco was not used for its nicotine, but perhaps it came from the stomachs of the ducks that had eaten it, or it was used as fuel for burning. The researchers noted that birds do not eat tobacco, and that tobacco lacks woody material and so burns too quickly to generate a fire of enough strength or duration for most cooking.

These findings suggest that people used tobacco for thousands of years before the unknown point in time at which humans first domesticated this plant, Duke said.

"People in the past were the ultimate botanists and identified the intoxicant values of tobacco quickly upon arriving in the Americas," Duke said.

Further research on this and other ancient sites with tobacco-use evidence could help shed light on the driving cultural forces behind the cultivation, use and subsequent domestication of tobacco, the researchers said.

"We have been working to get Indigenous input about the meaning and importance of the find," Duke said. "This will not only help us understand the find for the common scientific reasons, but also help us learn more about its values to the people whose forebears camped at the site and lived throughout the region. This is really important for the broader purpose of doing this science at all, so we can understand implications from a diverse set of interests."

The scientists detailed their findings online Monday (Oct. 11) in the journal Nature Human Behaviour.

Originally published on Live Science.

Young adults aren’t drinking as much as they used to. In fact, more than a quarter don’t drink alcohol at all, recent surveys show.

It’s good news for health. But there is also a downside in the data: While alcohol use is falling among 18-to-22-year-olds, marijuana use is inching upward. The number of young adults using both alcohol and marijuana is also rising, heightening concerns about a future surge in substance abuse problems, new research shows.

I am a professor of psychology at Texas State University who has been studying young adult and adolescent substance use for over 15 years. A key interest of mine is how substance use changes over adolescence and young adulthood. It is a period of profound change: A 13-year-old is very different from a 25-year-old in nearly every way.

With colleagues at the University of Michigan, the University of Central Florida and Iowa State University, I have been investigating trends in alcohol and marijuana use in young adults to better understand how use changes with age. The latest numbers offer both hope and concern.

Gen Z is breaking stereotypes

There are reasons for the stereotype of hard-drinking, substance-using young adults, as photos and videos from bars and college parties will attest. But surveys and our analysis suggest that binge drinking isn’t as common as people may believe it is.

Using data from the annual National Survey on Drug Use and Health, we found that in 2018 nearly 30% of college-age adults, ages 18-22, had not had a single alcoholic drink during the previous year, compared with fewer than a quarter in 2002. Over 60% had not used marijuana at all.

Among 18-to-25-year-olds, the number who reported binge drinking in the previous year fell from 39% in 2015 to 34% in 2019. That may be influenced at least in part by beliefs that are forming in high school. Another survey shows that nearly three-quarters of high school seniors think their friends would disapprove of weekend binge drinking, up from just over half in the early 1980s.

Adolescents – typically 12 to 17 years of age – were more likely to avoid both alcohol and marijuana than they were two decades ago, part of a larger trend in declining substance use and risky behavior among adolescents seen in a variety of national surveys and data sources. In 2019, nearly 80% of adolescents had not used alcohol at all in the previous year, compared with 65% in 2002, and 87% had not used marijuana.

Using both marijuana and alcohol

The bad news is that the number of college-age young adults saying they used marijuana at least once in the previous year has increased, from 33% to 37%.

The vast majority who said they used marijuana also used alcohol. We found that the increase in young adults using both was a result of young adults who used alcohol taking up marijuana, too.

This increase in using both alcohol and marijuana is an important warning sign, because young adults in that group also had much higher rates of other illicit drug use, like cocaine, and prescription drug misuse, involving medications like opioids or benzodiazepines.

That may signal that a greater number will need substance use treatment in the coming years.

Why the changes?

One theory for the shifting trends in alcohol and marijuana use is that adolescent substance use is now starting at later ages.

The data support this: The numbers of adolescents starting alcohol use has declined somewhat, while more college-age adults are first-time alcohol and marijuana users. Why that shift is occurring is less clear, but one theory is that adolescents have been engaging in more virtual contact than face-to-face contact in recent years and they rarely use substances when they’re alone.

Changing regulations likely also play a role. Marijuana is now legal for medical or recreational use in an increasing number of states.

Attitudes toward alcohol and marijuana have also changed over the years, particularly for marijuana.

The Monitoring the Future study, which has tracked substance use in adolescents and young adults since 1975, indicates both a sharp decline in disapproval of marijuana among middle and high school students and a decline in how harmful they perceive marijuana to be. In fact, more young people in that age group now see more harm from regular alcohol use than disapprove of marijuana.

[Deep knowledge, daily. Sign up for The Conversation’s newsletter.]

How the pandemic will change young people’s habits with alcohol and marijuana isn’t yet clear. One survey conducted this spring when many restaurants and bars were closed found that adults over 30 were drinking alcohol 14% more often. However, when researchers in Australia homed in on younger adults in Gen Z, they found a different story: Older age groups may be drinking more, but with bars and restaurants closed, 44% of the college-age crowd reported drinking less.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Follow all of the Expert Voices issues and debates — and become part of the discussion — on Facebook and Twitter. The views expressed are those of the author and do not necessarily reflect the views of the publisher. This version of the article was originally published on Live Science.

Vaping may increase the risk of getting COVID-19, at least in teens and young adults, a new study suggests.

The researchers analyzed information from more than 4,300 U.S. teens and young adults, ages 13 to 24, who completed an online survey in early May, according to the study, published Tuesday (Aug. 11) in the Journal of Adolescent Health. Participants answered questions about their cigarette and e-cigarette use, as well as whether they had experienced symptoms of COVID-19, undergone testing or were diagnosed with the disease from a positive test.

Among those tested for COVID-19, e-cigarette users were five times more likely to be diagnosed with COVID-19, and those who used both e-cigarettes and traditional cigarettes ("dual users") were seven times more likely to be diagnosed with COVID-19, compared with those who did not use e-cigarettes or traditional cigarettes.

In addition, dual users were nearly five times more likely to report experiencing symptoms of COVID-19 at the time of the survey, regardless of whether they were tested, compared with non-users.

"Young people may believe their age protects them from contracting the virus or that they will not experience symptoms of COVID-19," study lead author Shivani Mathur Gaiha, a postdoctoral scholar at Stanford University School of Medicine, said in a statement. But this study shows that people who vape, or use cigarettes and e-cigarettes face increased risks."It's not just a small increase in risk; it's a big one,” Gaiha said.

The researchers don't know what causes the link, but they have a number of hypotheses. Both smoking and vaping are known to damage the lungs and affect the immune system, which may increase the risk of developing a COVID-19 infection after exposure to the virus, according to NBC.

In addition, behaviors such as repeatedly touching your face and mouth to use an e-cigarette, or sharing vaping products, could also increase the risk of infection. Although about half of the participants said they were sheltering in place, "that doesn't mean they're not in the backyard with a friend sharing their vaping product," study senior author Bonnie Halpern-Felsher, a professor of pediatrics at  Stanford University School of Medicine, told CNN.

However, the study only found an association between vaping and COVID-19 infection, and cannot prove that vaping led to the illness. But the study did take into account a number of factors that could infuence participants' risk of infection, such as their self-reported compliance with shelter-in-place orders and the rate of COVID-19 diagnoses in their state, as well as their age, sex, race/ethnicity, body mass index and socioeconomic status.

The researchers hope their results not only provide a warning to teens and young adults about the risks of vaping, but also encourage the U.S. Food and Drug Administration (FDA) to further tighten regulations on e-cigarettes and how they are sold to young people.

Recently, lawmakers sent a letter to FDA commissioner Dr. Stephen Hahn urging the FDA to temporarily clear the market of all e-cigarettes for the duration of the COVID-19 pandemic, CNN reported. The letter cites the current study as evidence that vaping is a risk factor for COVID-19.

Originally published on Live Science.  

The novel coronavirus causing COVID-19 seems to hit some people harder than others, with some people experiencing only mild symptoms and others being hospitalized and requiring ventilation. Though scientists at first thought age was the dominant factor, with young people avoiding the worst outcomes, new research has revealed a suite of features impacting disease severity. These influences could explain why some perfectly healthy 20-year-old with the disease is in dire straits, while an older 70-year-old dodges the need for critical interventions.

Underlying health conditions are thought to be an important factor influencing disease severity. Indeed, a study of more than 1.3 million COVID-19 cases in the United States, published June 15 in the journal Morbidity and Mortality Weekly Report, found that rates of hospitalizations were six times higher and rates of death were 12 times higher among COVID-19 patients with underlying conditions, compared with patients without underlying conditions. The most commonly reported underlying conditions were heart disease, diabetes and chronic lung disease. 

In general, risk factors for more severe COVID-19 outcomes include:
Age
Diabetes (type 1 and type 2)
Heart disease and hypertension
Smoking
Blood type
Obesity
Genetic factors

Age

About 8 out of 10 deaths associated with COVID-19 in the U.S. have occurred in adults ages 65 and older, according to the U.S. Centers for Disease Control and Prevention (CDC). The risk of dying from the infection, and the likelihood of requiring hospitalization or intensive medical care, increases significantly with age. For instance, adults ages 65-84 make up an estimated 4-11% of COVID-19 deaths in the U.S, while adults ages 85 and above make up 10-27%. 

The trend may be due, in part, to the fact that many elderly people have chronic medical conditions, such as heart disease and diabetes, that can exacerbate the symptoms of COVID-19, according to the CDC. The ability of the immune system to fight off pathogens also declines with age, leaving elderly people vulnerable to severe viral infections, Stat News reported.

Related: Coronavirus in the US: Latest COVID-19 news and case counts

Diabetes

Diabetes mellitus — a group of diseases that result in harmful high blood sugar levels — also seems to be linked to risk of more severe COVID-19 infections. 

The most common form in the U.S. is type 2 diabetes, which occurs when the body's cells don't respond to the hormone insulin. As a result, the sugar that would otherwise move from the bloodstream into cells to be used as energy just builds up in the bloodstream. (When the pancreas makes little to no insulin in the first place, the condition is called type 1 diabetes.)

In a review of 13 relevant studies, scientists found that people with diabetes were nearly 3.7 times more likely to have a critical case of COVID-19 or to die from the disease compared with COVID-19 patients without any underlying health conditions (including diabetes, hypertension, heart disease or respiratory disease), they reported online April 23 in the Journal of Infection.

Even so, scientists don't know whether diabetes is directly increasing severity or whether other health conditions that seem to tag along with diabetes, including cardiovascular and kidney conditions, are to blame. 

That fits with what researchers have seen with other infections and diabetes. For instance, flu and pneumonia are more common and more serious in older individuals with type 2 diabetes, scientists reported online April 9 in the journal Diabetes Research and Clinical Practice. In a literature search of relevant studies looking at the link between COVID-19 and diabetes, the authors of that paper found a few possible mechanisms to explain why a person with diabetes might fare worse when infected with COVID-19. These mechanisms include: "Chronic inflammation, increased coagulation activity, immune response impairment and potential direct pancreatic damage by SARS-CoV-2."

Related: 13 coronavirus myths busted by science 

Mounting research has shown the progression of type 2 diabetes is tied to changes in the body's immune system. This link could also play a role in poorer outcomes in a person with diabetes exposed to SARS-CoV-2, the virus that causes COVID-19. 

No research has looked at this particular virus and immune response in patients with diabetes; however, in a study published in 2018 in the Journal of Diabetes Research, scientists found through a review of past research that patients with obesity or diabetes showed immune systems that were out of whack, with an impairment of white blood cells called Natural Killer (NK) cells and B cells, both of which help the body fight off infections. The research also showed that these patients had an increase in the production of inflammatory molecules called cytokines. When the immune system secretes too many cytokines,a so-called "cytokine storm" can erupt and damage the body's organs. Some research has suggested that cytokine storms may be responsible for causing serious complications in people with COVID-19, Live Science previously reported. Overall, type 2 diabetes has been linked with impairment of the very system in the body that helps to fight off infections like COVID-19 and could explain why a person with diabetes is at high risk for a severe infection.

Not all people with type 2 diabetes are at the same risk, though: A study published May 1 in the journal Cell Metabolism found that people with diabetes who keep their blood sugar levels in a tighter range were much less likely to have a severe disease course than those with more fluctuations in their blood sugar levels. 

People with type 1 diabetes (T1D) are also at elevated risk of adverse outcomes, a small study published in Diabetes Care suggests. The study, coordinated by  T1D Exchange — a nonprofit research organization focused on therapies for those with type 1 diabetes — found that of 64 people with either COVID-19 or COVID-19-like symptoms, two died. Nearly 4 in 10 people had to be treated in a hospital. And nearly a third experienced diabetic ketoacidosis — a potentially deadly condition in which the body experiences a shortage of insulin and blood sugar levels rise dangerously high.  The average patient was about 21 years old, suggesting that risks could be potentially higher for older age groups.

Heart disease and hypertension

People with conditions that affect the cardiovascular system, such as heart disease and hypertension, generally suffer worse complications from COVID-19 than those with no preexisting conditions, according to the American Heart Association. That said, historically healthy people can also suffer heart damage from the viral infection. 

The first reported coronavirus death in the U.S., for instance, occurred when the virus somehow damaged a woman's heart muscle, eventually causing it to burst, Live Science reported. The 57-year-old maintained good health and exercised regularly before becoming infected, and she reportedly had a healthy heart of "normal size and weight." A study of COVID-19 patients in Wuhan, China, found that more than 1 in 5 patients developed heart damage — some of the sampled patients had existing heart conditions, and some did not. 

In seeing these patterns emerge, scientists developed several theories as to why COVID-19 might hurt both damaged hearts and healthy ones, according to a Live Science report. 

In one scenario, by attacking the lungs directly, the virus might deplete the body's supply of oxygen to the point that the heart must work harder to pump oxygenated blood through the body. The virus might also attack the heart directly, as cardiac tissue contains angiotensin-converting enzyme 2 (ACE2) — a molecule that the virus plugs into to infect cells. In some individuals, COVID-19 can also kickstart an overblown immune response known as a cytokine storm, wherein the body becomes severely inflamed and the heart could suffer damage as a result.

Smoking

People who smoke cigarettes may be prone to severe COVID-19 infections, meaning they face a heightened risk of developing pneumonia, suffering organ damage and requiring breathing support. A study of more than 1,000 patients in China, published in the New England Journal of Medicine, illustrates this trend: 12.3% of current smokers included in the study were admitted to an ICU, were placed on a ventilator or died, as compared with 4.7% of nonsmokers. 

Cigarette smoke might render the body vulnerable to the coronavirus in several ways, according to a recent Live Science report. At baseline, smokers may be vulnerable to catching viral infections because smoke exposure dampens the immune system over time, damages tissues of the respiratory tract and triggers chronic inflammation. Smoking is also associated with a multitude of medical conditions, such as emphysema and atherosclerosis, which could exacerbate the symptoms of COVID-19.

A recent study, posted March 31 to the preprint database bioRxiv, proposed a more speculative explanation as to why COVID-19 hits smokers harder. The preliminary research has not yet been peer-reviewed, but early interpretations of the data suggest that smoke exposure increases the number of ACE2 receptors in the lungs — the receptor that SARS-CoV-2 plugs into to infect cells. 

Many of the receptors appear on so-called goblet and club cells, which secrete a mucus-like fluid to protect respiratory tissues from pathogens, debris and toxins. It's well-established that these cells grow in number the longer a person smokes, but scientists don't know whether the subsequent boost in ACE2 receptors directly translates to worse COVID-19 symptoms. What's more, it's unknown whether high ACE2 levels are relatively unique to smokers, or common among people with chronic lung conditions.

Obesity

Several early studies have suggested a link between obesity and more severe COVID-19 disease in people. One study, which analyzed a group of COVID-19 patients who were younger than the age of 60 in New York City, found that those who were obese were twice as likely as non-obese individuals to be hospitalized and were 1.8 times as likely to be admitted into critical care. 

"This has important and practical implications" in a country like the U.S. where nearly 40% of adults are obese, the authors wrote in the study, which was accepted into the journal Clinical Infectious Diseases but not yet peer-reviewed or published. Similarly, another preliminary study that hasn't yet been peer-reviewed found that the two biggest risk factors for being hospitalized from the coronavirus are age and obesity. This study, published in medRxiv looked at data from thousands of COVID-19 patients in New York City, but studies from other cities around the world found similar results, as reported by The New York Times.

A preliminary study from Shenzhen, China, which also hasn't been peer-reviewed, found that obese COVID-19 patients were more than twice as likely to develop severe pneumonia as compared with patients who were normal weight, according to the report published as a preprint online in the journal The Lancet Infectious Diseases. Those who were overweight, but not obese, had an 86% higher risk of developing severe pneumonia than did people of "normal" weight, the authors reported. Another study, accepted into the journal Obesity and peer-reviewed, found that nearly half of 124 COVID-19 patients admitted to an intensive care unit in Lille, France, were obese.

It's not clear why obesity is linked to more hospitalizations and more severe COVID-19 disease, but there are several possibilities, the authors wrote in the study. Obesity is generally thought of as a risk factor for severe infection. For example, those who are obese had longer and more severe disease during the swine flu epidemic, the authors wrote. Obese patients might also have reduced lung capacity or increased inflammation in the body. A greater number of inflammatory molecules circulating in the body might cause harmful immune responses and lead to severe disease.

Blood type

Blood type seems to be a predictor of how susceptible a person is to contracting SARS-CoV-2, though scientists haven't found a link between blood type per se and severity of disease.

Jiao Zhao, of The Southern University of Science and Technology, Shenzhen, and colleagues looked at blood types of 2,173 patients with COVID-19 in three hospitals in Wuhan, China, as well as blood types of more than 23,000 non-COVID-19 individuals in Wuhan and Shenzhen. They found that individuals with blood types in the A group (A-positive, A-negative and AB-positive, AB-negative) were at a higher risk of contracting the disease compared with non-A-group types. People with O blood types (O-negative and O-positive) had a lower risk of getting the infection compared with non-O blood types, the scientists wrote in the preprint database medRxiv on March 27; the study has yet to be reviewed by peers in the field.

In a more recent study of blood type and COVID-19, published online April 11 to medRxiv, scientists looked at 1,559 people tested for SARS-CoV-2 at New York Presbyterian hospital; of those, 682 tested positive. Individuals with A blood types (A-positive and A-negative) were 33% more likely to test positive than other blood types and both O-negative and O-positive blood types were less likely to test positive than other blood groups. (There's a 95% chance that the increase in risk ranges from 7% to 67% more likely.) Though only 68 individuals with an AB blood type were included, the results showed this group was also less likely than others to test positive for COVID-19. 

The researchers considered associations between blood type and risk factors for COVID-19, including age, sex, whether a person was overweight, other underlying health conditions such as diabetes mellitus, hypertension, pulmonary diseases and cardiovascular diseases. Some of these factors are linked to blood type, they found, with a link between diabetes and B and A-negative blood types, between overweight status and O-positive blood groups, for instance, among others. When they accounted for these links, the researchers still found an association between blood type and COVID-19 susceptibility. When the researchers pooled their data with the research by Zhao and colleagues out of China, they found similar results as well as a significant drop in positive COVID-19 cases among blood type B individuals.

Why blood type might increase or decrease a person's risk of getting SARS-CoV-2 is not known. A person's blood type indicates what kind of certain antigens cover the surfaces of their blood cells; These antigens produce certain antibodies to help fight off a pathogen. Past research has suggested that at least in the SARS coronavirus (SARS-CoV), anti-A antibodies helped to inhibit the virus; that could be the same mechanism with SARS-CoV-2, helping blood group O individuals to keep out the virus, according to Zhao's team.

Genetic factors

Many medical conditions can worsen the symptoms of COVID-19, but why do historically healthy people sometimes fall dangerously ill or die from the virus? Scientists suspect that certain genetic factors may leave some people especially susceptible to the disease, and many research groups aim to pinpoint exactly where those vulnerabilities lie in our genetic code. 

In one scenario, the genes that instruct cells to build ACE2 receptors may differ between people who contract severe infections and those who hardly develop any symptoms at all, Science magazine reported. Alternatively, differences may lie in genes that help rally the immune system against invasive pathogens, according to a recent Live Science report.

For instance, a study published April 17 in the Journal of Virology suggests that specific combinations of human leukocyte antigen (HLA) genes, which train immune cells to recognize germs, may be protective against SARS-CoV-2, while other combinations leave the body open to attack. HLAs represent just one cog in our immune system machinery, though, so their relative influence over COVID-19 infection remains unclear. Additionally, the Journal of Virology study only used computer models to simulate HLA activity against the coronavirus; clinical and genetic data from COVID-19 patients would be needed to flesh out the role of HLAs in real-life immune responses.

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Originally published on Live Science.  

Smokers may be prone to severe COVID-19 infections, in part, because their lungs contain an abundance of entry points that the virus can exploit.

COVID-19 infections begin at the ACE2 receptor, a protein nestled on the surface of cells throughout the body, including in the upper and lower respiratory tracts. The coronavirus that causes COVID-19, known as SARS-CoV-2, must plug into the ACE2 receptor in order to inject its genetic material into cells, replicate and spread. Now, preliminary research suggests that lungs exposed to cigarette smoke accumulate abnormally large numbers of ACE2 receptors, which may leave the organ vulnerable to damage inflicted by the coronavirus.      

"It has been reported that smokers who get COVID-19 tend to have more severe infections than individuals who aren’t smokers," co-author Jason Sheltzer, a research fellow at the Cold Spring Harbor Laboratory in New York, told Live Science in an email. An increase in ACE2 receptors "could be one reason — of many — why smokers get so sick from coronavirus," he said. 

The study, posted March 31 to the preprint database bioRxiv, has not been peer-reviewed and its premise remains "fairly speculative," said Dr. Stephanie Christenson, an assistant professor in the Division of Pulmonary, Critical Care, Allergy, and Sleep Medicine at University of California, San Francisco, who was not involved in the study. 

"If ACE2 expression is high, if ACE2 expression is low, and what that means toward your overall prognosis — I don't think we actually know that yet," Christenson told Live Science. 

"Smoking does a lot of things to the body," Sheltzer added. "And it’s possible that [smoking's] effect on ACE2 levels isn’t the most important factor."

Smoking linked to severe infection 

Mounting evidence suggests that, compared with nonsmokers, people who smoke cigarettes face a higher risk of developing severe complications and dying from COVID-19 infections. 

For instance, a study of more than 1,000 patients in China, published in the New England Journal of Medicine, found that smokers with COVID-19 were more likely to require intensive medical interventions than those who didn't smoke. In the study, 12.3% of current smokers were admitted to an ICU, were placed on a ventilator or died, as compared with only 4.7% of nonsmokers. 

Smokers may be particularly vulnerable to COVID-19 for several reasons, but the ACE2 receptor hypothesis "provides a holistic, mechanistic link" between smoking and severe infection, Jaber Alqahtani, a researcher in Respiratory Medicine at University College London, told Live Science in an email. If future research bolsters the link between receptor quantity and disease severity, drugs that block or reduce the sensitivity of ACE2 receptors could potentially be used as treatments, he added. 

Related: 10 deadly diseases that hopped across species 

More gateways into the lung 

To draw the connection between ACE2 receptors and smoking, Sheltzer and software engineer Joan Smith, a member of Sheltzer's lab, examined lung and respiratory tissue samples from deceased mice, rats and humans, as well as samples collected during human lung surgeries. The number of ACE2 receptors in the lungs did not vary between rodents of different ages or different sexes, and the same trends appeared in humans. 

As age and sex appeared unrelated to ACE2 quantity, the researchers wondered if cigarette smoke exposure might make a difference.

The team inspected tissue samples from mice that had been exposed to diluted cigarette smoke for zero, 2, 3 or 4 hours a day over the course of five months. They found that, the more smoke exposure, the more ACE2 receptors studded the animals' lungs. Compared with unexposed mice, the mice that received the highest dose of cigarette smoke accumulated about 80% more ACE2 receptors in their lungs. The researchers then compared the lungs of human smokers against those who never smoked, and again, they found a similar trend: Smokers’ lungs contained 40% to 50% more ACE2 receptors than those of nonsmokers.  

The quantity of ACE2 receptors varied by pack-years — a measure of how many packs of cigarettes a person smoked per day multiplied by the number of years the person smoked. For example, among smokers who had undergone thoracic surgery, people who smoked more than 80 pack-years showed a 100% increase in ACE2 receptors compared with people who smoked fewer than 20 pack-years, the authors noted.  

While smoke-exposed tissues harbored more ACE2 receptors, the team could not tell which specific cells contained the receptor. By examining which proteins appeared in what cells, the team found that ACE2 appeared on cells that process oxygen and carbon dioxide in the lungs, known as alveolar type 2 cells. But primarily, the receptors appeared on cells that secrete a mucus-like fluid into the respiratory tracts, known as goblet and club cells. Nonsmokers carry most of their goblet and club cells in their nose and throat, but in smokers, the cells begin to accumulate also in the lungs, the authors found.   

"What they're suggesting is that when you smoke you have an increase in goblet cells [in the lower respiratory tract], and that's definitely true," Christenson said. 

Evidence that smoking boosts the number of secretory cells in the lungs has been reported for decades, according to a 1999 report in the American Journal of Respiratory and Critical Care Medicine. The sticky mucus generated by goblet and club cells acts as a protective barrier, capturing debris, aerosols, smoke and pathogens that get sucked into the respiratory system, Christenson said. When people inhale smoke into their lungs, the organ reinforces its defenses by building more secretory cells and increasing mucus production. The same process occurs in individuals exposed to high levels of air pollution, Christenson said. 

Still a hypothesis 

While high numbers of goblet and club cells, laden with ACE2 receptors, may explain why smokers fall severely ill of COVID-19, the exact relationship between ACE2 and disease prognosis "remains to be demonstrated," Sheltzer and Smith noted. 

Smoking is associated with many comorbidities — multiple medical conditions that appear simultaneously — including emphysema and compromised immune function, which likely exacerbate COVID-19 infections, they wrote. In general, smokers already face a heightened risk of catching viral infections, likely due to their having depressed immune systems, tissue damage and chronic inflammation in the respiratory tracts, Christenson added.

High ACE2 levels may not be unique to smokers, but instead may be common among people with lung conditions, in general, the authors noted. The team did analyze tissue samples from patients with asthma and the inflammatory disease sarcoidosis, however, and these did not contain abnormal quantities of the receptor.

To tease out how ACE2 levels relate to lung disease, in general, future research could focus on patients with chronic obstructive pulmonary disease (COPD), bronchitis, pneumonia or lung diseases triggered by bacterial, viral or fungal infections, Alqahtani said. If they also have elevated levels of ACE2 receptors on their cells, that could help clarify whether cigarette smoke poses a singular threat to COVID-19 patients, or if other lung conditions present risks for the same reason.

If smoking does prove uniquely dangerous for COVID-19 patients, however, the study does offer a potential solution.

"We show that former smokers have lower levels of ACE2 than current smokers" — about 30% lower, Sheltzer said. "It’s conceivable that quitting smoking could be beneficial to decrease COVID-19 susceptibility, for multiple reasons."

"Indeed, it also allows us to consider campaigns and programs aimed at helping smokers quit as a preventative strategy going forward," Alqahtani added.

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Originally published on Live Science. 

In a major blow to the vaping industry, the American Medical Association has called for a ban on e-cigarettes and vaping products that the FDA doesn't deem tobacco cessation devices.

As a tobacco researcher and former smoker, I don't care much about the health of the vaping and e-cigarette industry. But I do care about the health of smokers, and I wonder whether policy makers may now be reacting too strongly to e-cigarettes.

Although e-cigarettes in the U.S. are not regulated or approved by the FDA as smoking cessation devices, they may have helped thousands quit cigarettes.

I also wonder to what degree fear and hysteria, rather than evidence, might be informing this crucial public health topic. Smoking is the nation's number one cause of preventable death, claiming close to half a million lives a year.

Info overlooked, left out?

As of Nov. 20, 42 people have died, and more than 2,000 have been sickened from vaping-related illnesses. The New York Times reported last month on the youngest person to die from vaping, a 17-year old boy from the Bronx.

If your reaction to this story is to call for comprehensive vaping bans, you are not alone. The outbreak of vaping-related pulmonary illnesses has generated substantial news coverage, with stories of vaping-related deaths emerging frequently, and likely contributing to several states implementing vaping bans.

Reporting and public discourse often leave important data out of conversations, however.

For example, the National Academies of Sciences' report, published in January 2018, reviewed all of the evidence to date on e-cigarettes, and found that, except for nicotine, toxicant exposure from e-cigarettes is lower than from combustible cigarettes.

Although "less harmful" does not mean "harmless," harm minimization is likely the most productive approach for persistent smokers. That is, although nicotine itself poses risks to some vulnerable groups, there is little evidence that nicotine alone causes cardiovascular disease, cancer and pulmonary diseases when decoupled from smoke.

The National Academies' conclusion about e-cigarettes being less harmful than cigarettes presumes that vaping products are being used as intended. This is not always the case. In fact, recent findings indicate that most lung injury cases have involved vaping THC products, and/or products obtained from informal and poorly regulated markets, with as few as 10% of cases involving nicotine alone.

Although some evidence suggests that laws legalizing medical and recreational cannabis are associated with youth THC vaping, the potential relationship between vaping injuries and marijuana legalization is sparsely acknowledged.

An issue unique to the U.S.?

Reports on vaping also tend to leave out that vaping illnesses are a uniquely American problem. In the U.K., where e-cigarettes are regulated as cessation devices, comparable lung illnesses are not occurring. In fact, clinical trials conducted outside the U.S. have found e-cigarettes to be as effective as, or more effective than, nicotine replacement therapy at promoting cessation.

In the U.S., where e-cigarettes are regulated as tobacco products rather than cessation devices, comparable trials are lacking.

However, recent findings from one nationally representative survey indicated that smokers who used e-cigarettes daily were significantly more likely to stop smoking for at least two years compared to non-e-cigarette users — 11% versus 6%.

These results were consistent with another national study of about 5,000 adults. In that study, 337 (6.90%) quit smoking cigarettes and 778 (16.69%) substantially reduced their smoking rate, with about 14% of quitters and 15% of reducers reporting e-cigarette use.

One caveat is that officials and scholars cannot determine whether using e-cigarettes specifically facilitated quitting smoking, as some may have quit over time anyway even without e-cigarettes.

Undermining gains?

One significant risk of vaping alarmism is undermining the gains the nation has made in reducing cigarette smoking, including youth smoking. National data among middle and high school students show that cigarette smoking has continued to decline even as vaping explodes.

Some studies have suggested that e-cigarettes serve as a gateway to cigarettes for some teens. However, the most recent study of the gateway question found that among 12,000 U.S. youth, those who vaped were more likely to try cigarettes, but not more likely to become regular smokers. In simpler terms, the relationship between vaping and smoking is likely explained by shared risk factors — that is, the same characteristics that predict teen vaping also predict teen smoking.

The group most often neglected in our conversations about vaping is current cigarette smokers. Although smoking prevalence today is at an all-time low of 13.7%, smoking is increasingly concentrated among the most vulnerable — those with mental illness, substance use disorders or living in poverty.

It is exceedingly difficult to promote cessation among these "hardened" smokers. That's why health professionals and policy makers should be open to allowing, or even encouraging, these smokers to manage their nicotine addiction by transitioning from combusted to non-combusted sources of nicotine.

Just as opioid maintenance therapy is the standard of care for individuals with opioid use disorder, long-term nicotine maintenance should be an option for those addicted to nicotine. I have been "nicotine-maintained" for about five years, primarily with nicotine replacement therapy, but at one point with a "cig-a-like" vaping product. Five years is longer than the recommended 8-12 weeks of nicotine replacement therapy, but the prolonged therapy has allowed me to function effectively as a nonsmoker.

Today's often economically disadvantaged smokers likely cannot afford five years of nicotine replacement therapy. Although Medicaid recipients smoke at higher rates than those with private health insurance, most states have limited coverage for tobacco cessation treatment. Until nicotine replacement therapy is more affordable, we ought to consider the implications of decisions that dramatically limit smokers' access to alternative, less harmful sources of nicotine, such as comprehensive vaping bans.

In fact, one effect of Massachusetts' statewide vaping ban is a rise in cigarettes sales as former smokers reliant on e-cigarettes return to the most toxic, dependence-producing tobacco product available.

To be clear: The scientific evidence to date does not suggest that we should all be advocates for vaping. However, I believe we should have more reasoned conversations about vaping that are grounded in science, and acknowledge that while 39 deaths is 39 too many, there are half a million smoking-associated deaths each year in the U.S. Advocating for these smokers having easy and affordable access to less harmful sources of nicotine is imperative to improving U.S. public health.

[You're smart and curious about the world. So are The Conversation's authors and editors. You can read us daily by subscribing to our newsletter.]

This article was originally published at The Conversation. The publication contributed the article to Live Science's Expert Voices: Op-Ed & Insights.

Young people who use marijuana frequently are more than twice as likely to have a stroke compared to those who don't use the drug at all, according to a new study. 

The findings, which will be presented next week at the annual American Heart Association (AHA) Scientific Sessions meeting in Philadelphia, add to a growing body of research linking marijuana use to an increased risk of cardiovascular problems. The new study, which will also be published in an upcoming issue of the journal Stroke, is one of the first to specifically focus on the risk of stroke in young cannabis users (under age 45).

The researchers analyzed results from a national survey, called the Behavioral Risk Factor Surveillance System, which had published data on marijuana use and stroke incidence.

Related: 7 Ways Marijuana May Affect the Brain

The authors compared the frequency of marijuana use to the incidence of stroke in people ages 18 to 44 years old. Among the 43,860 participants, 13.6% had used marijauna in the last 30 days. (The data doesn't specify the way in which participants used marijuana, though a majority of the survey respondents said they smoked it). Marijuana users tended to also report heavy drinking and use of tobacco cigarettes.

The authors found that frequent marijuana users, or people who used marijuana more than 10 days a month, but who did not use tobacco products were nearly 2.5 times more likely to have a stroke than people who did not use marijuana, according to a statement. 

For those who used marijuana frequently and also smoked cigarettes or e-cigarettes, the risk was even greater. These individuals were nearly three times more likely to have a stroke, compared with those who didn't use either marijuana or cigarettes. 

But these findings show only an association and cannot prove that marijuana use causes strokes. The authors noted that other substances, such as alcohol, may also influence the risk of stroke seen in the study, even though the scientists attempted to adjust for additional substance use in their analysis.

What's more, even if there is a cause-and-effect relationship between marijuana use and stroke, researchers don't exactly know how the drug might be leading to stroke. Marijuana use has been linked to an increased number of blood clots, which might, in turn, increase the risk of stroke, according to a previous Live Science report.

Cannabis might also trigger "reversible cerebral vasoconstriction," or a temporary narrowing of the blood vessels in the brain that has been linked with stroke, said lead author Dr. Tarang Parekh, a health policy researcher at George Mason University in Virginia. 

"In the current discussion of legalization of marijuana in the United States, we believe this study was a crucial step towards" understanding stroke risk in young marijuana users, Parekh told Live Science. "Even though cannabis is not [as] harmful or addictive as other substances, we cannot ignore its potential health risks."

A separate study, which will also be presented at the AHA meeting next week, found a link between marijuana use and an increased risk of heart arrhythmia (or rhythm problems) in young adults. The authors found that young people, or those between the ages of 15 and 34, who have cannabis-use disorder had a 47% to 52% increased risk of being hospitalized because of an arrhythmia. 

The latter study has not yet been published in a peer-reviewed journal.

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Originally published on Live Science.

The number of potential cases of severe lung illnesses linked to vaping has increased to 193,  the Centers for Disease Control and Prevention (CDC) announced today (Aug. 23). One adult patient in Illinois has died. 

The CDC is investigating the string of vaping-related illnesses, now reported in 22 states. The investigation is ongoing, and it's still unclear if the cases were linked or what kinds of products the patients had used, according to the CDC.

"Even though cases appear similar, it isn't clear if these cases have a common cause or if they are different cases with similar presentations," Ileana Arias, the acting deputy director for noninfectious diseases at the CDC, said at the news briefing.

Related: 4 Myths About E-Cigarettes

However, all of the patients reported having used electronic cigarettes or vaping products in the past couple of months, she said. In many cases, the patients also reported having used products containing THC, the active ingredient in marijuana.

Several states are conducting their own investigations into the string of illnesses and reporting back to the CDC, while the Food and Drug Administration (FDA) is helping to test and identify products and devices that the patients may have used. The FDA has received product samples from a number of states and is starting to analyze them for specific constituents. 

"We don't have any specific information to share at this time," said Mitch Zeller, the director of the Center for Tobacco Products at the FDA.

"It's possible that the reported cases could have been occurring before this investigation was even initiated," said Brian King, the deputy director for research translation in the Office on Smoking and Health at the CDC. It could just be that "we weren't necessarily capturing them."

"We do know that e-cigarette aerosol is not harmless," he said. These products contain many chemicals, both listed and unlisted, that can be problematic for the lungs, such as ultrafine particulates, heavy metals like lead, volatile organic compounds and cancer-causing chemicals, King said. Even e-cigarette flavorings, such as those that make it taste "buttery," have compounds previously linked to severe respiratory illness, he said.

That being said, the CDC has not identified specific products or ingredients linked to any of these cases. 

In Illinois, 22 patients, between the ages of 17 and 38, were hospitalized from severe lung illness associated with vaping. The Illinois patient who died was an adult, said Dr. Jennifer Layden, the chief medical officer and state epidemiologist for the Illinois Department of Public Health.

Again, it's not clear what products these patients used. The only "consistent information is that all patients have vaped in recent months," she said.

The FDA encourages the public to submit detailed reports of any unexpected tobacco- or e-cigarette-related health or product issues.

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Originally published on Live Science.

UPDATE: On Aug. 21, the Centers for Disease Control and Prevention announced that there are now 149 possible cases of severe lung illness associated with vaping reported in 15 states. 

Vaping has sent nearly 100 people, mostly teens and young adults, to the hospital with lung illnesses in the last couple of weeks. 

The Centers for Disease Control and Prevention (CDC) is investigating 94 possible cases of "severe lung illness associated with vaping," which have been reported in 14 states as of Aug 17, according to a statement from the agency. It's unclear what's causing the illnesses or even if there is a link between patients' symptoms and the kinds of products they used.

But the patients have reported vaping various substances, including nicotine and marijuana. Some of the patients said they bought their e-cigarette products on the street, according to a previous Live Science report. What could be harming them?

Related: 4 Myths About E-Cigarettes

Based on the limited information, the "most likely" explanation is that a toxic chemical in the electronic cigarettes is causing a "severe reactive, inflammatory" response in the patients' lungs, said Dr. Michael Siegel, a professor of community health sciences at Boston University's School of Public Health. 

If that's the case, this chemically induced lung injury could lead to several severe lung conditions. One condition, known as  acute respiratory distress syndrome (ARDS), has been associated with the inhalation of toxic fumes. Another condition is chemical pneumonitis, or inflammation of the lungs that is caused by inhaling irritants, Siegel told Live Science. 

But "it is very unlikely that this is being caused purely by nicotine-containing e-liquids," he added. Rather, the reaction is probably caused by a "contaminant that is present in certain formulations of cannabis products" sold for vaping, possibly on the streets, he said. 

For example, pneumonitis has been linked to the practice of "dabbing," or inhalation of butane hash oil, a concentrated form of marijuana that contains high levels of the drug's active compound, THC. Heating butane hash oil to high temperatures may result in the formation of chemicals that are toxic to the lungs, according to a report published in the journal Respiratory Medicine Case Reports last January. 

But other experts say that noncannabis e-cigarettes, those that contain nicotine instead of THC, could also cause such reactions. A group of researchers recently found that nicotine releases potentially harmful enzymes — molecules that have a role in breaking down proteins in the body — into the lungs. Those researchers published their results on Aug. 7 in the American Journal of Respiratory and Critical Care Medicine.

These enzymes are known to cause lung damage, said Robert Tarran, the senior author of that study and a professor at the University of North Carolina School of Medicine. At least in part, "I think that … the teenagers are taking in very high amounts of nicotine that is then affecting the immune cells in the lung," he said.

Previous research into e-cigarettes has found multiple chemicals in the vapor that can damage cells and trigger inflammation in the lungs and in the bloodstream, said Dr. Laura Crotty Alexander, an associate professor of medicine at the University of California, San Diego. "It could be a particular chemical in the e-cigarette vapor or multiple different chemicals leading to acute lung injury," Crotty said.

An acute lung injury means that the cells of the lungs have been damaged and the immune system has responded to try and stop the damage and heal the lungs. Because of inflammation and cell damage, gas exchange in the body is "impaired" such that patients are short of breath, deprived of oxygen and often coughing, Alexander said. This could be caused by store-bought or street-bought e-cigarettes, she said.

A study published today (Aug. 20) found that right after vaping a non-nicotine-containing e-cigarette, participants had much less oxygen flowing through their blood. "We could only conjecture at this point" about whether this finding could help explain the mysterious vaping-related illness, said, Felix Wehrli, senior author of the study and a professor of radiologic science and biophysics at the University of Pennsylvania Perelman School of Medicine.

One possibility is that these patients' lungs could not take up oxygen properly, he said. If that was the case, the lungs might have resorted to taking up more oxygen from the blood. This phenomenon would also explain why Wehrli and colleagues saw a reduction of oxygen flowing through blood vessels after vaping in their study, he said.

In part because e-cigarettes are often thought of as being safer than regular cigarettes, since they don't contain tobacco, there has been a surge in e-cigarette use in recent years, especially among teens.

Most e-cigarette liquids contain three major components: propylene glycol, glycerol and nicotine, Alexander said. But when you heat these components into a vapor, you create completely different chemicals, some of which are toxic, such as formaldehyde and acrolein. "But because there's new e-cigarettes and e-liquids coming on market at least every month, it's impossible to keep up with all the different chemicals that are being sold and breathed in," she said. 

What's more, the Food and Drug Administration isn't actively regulating these devices, she said. The administration doesn't require companies to label products with all the ingredients, and the ones that are labeled are often wrong, she said. As for the e-cigarettes sold on the street, what's in them is even more unclear, she said. So her advice to teenagers is "if somebody hands you one of these devices at a party, do not use it," she said. "Because you have no idea what's in it."

In any case, according to the CDC statement, there isn't conclusive evidence that an infectious disease is causing the illnesses. The investigation is ongoing, and the agency said it will share more information as it becomes available.

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Originally published on Live Science.

Vaping may create dangerous toxins that temporarily reduce blood flow and damage blood vessels, according to a new study. What's more, these effects were seen when people used e-cigarettes that did not contain nicotine.

While the dangers of smoking cigarettes are very well established, the health effects of smoking electronic cigarettes aren’t clear. Recently, the Centers for Disease Control and Prevention announced an investigation into a string of mysterious vaping-related illnesses that have landed nearly 100 people in the hospital. 

But knowing that the effects of vaping may spread further than the lungs, the researchers wanted to investigate the effects of e-cigarettes on the body's blood vessels and blood circulation. 

To do this, they recruited 31 healthy adults who did not smoke; researchers tied a tight cuff around one thigh of each participant. They kept this cuff on for a couple minutes, restricting blood flow through a major vein and artery in the leg, known as the femoral artery and vein.

Related: 4 Myths About E-Cigarettes

Then, the researchers took the cuff off and used magnetic resonance imaging (MRI) to measure participants' blood flow. Typically, when blood is restricted in this way, there will be a demand for increased blood flow when the cuff is removed, because the tissue is starved of oxygen and nutrients, said senior author Felix Wehrli, a professor of radiologic science and biophysics at the University of Pennsylvania Perelman School of Medicine. 

Indeed, the researchers saw that when they removed the cuff,  participants' blood flowed much faster, reaching a peak velocity before dropping back down to normal levels after a minute or so. Next, the participants took 16 puffs of an e-cigarette that did not contain nicotine and once again had a cuff tied to their legs and their blood vessels imaged.

Post-vaping, the participants' blood vessels did not dilate, or widen, as much as before to let blood through. In fact, after a participant smoked, the vessels dilated, on average, 34% less than they did before vaping. What's more, blood acceleration was 25.8%  slower, peak blood flow — the maximum blood flow through the vessels— was reduced by 17.5%, and oxygen levels in the vessels dropped by 20%.

The findings suggest that vaping, even just once, leads to temporary changes that impair blood vessel function, the authors said.

"This normal [blood circulation] response is blunted by e-cigarette exposure," and the reason is likely because of the ingredients found in e-cigarettes, Wehrli told Live Science. E-cigarettes come in a wide variety of brands and flavorings and so they may have a giant list of ingredients. But the basic ingredients, propylene glycol and glycerol, are pretty much the same, he added. 

When propylene glycol and glycerol are heated to high temperatures, they form other substances that are known to be toxic, he said. In a previous paper, the same team showed that smoking e-cigarettes actually caused a "toxic immune response" in the endothelium, or blood vessel lining. 

However, these studies looked only at the very short-term effects of vaping, and participants' blood vessels returned to normal within an hour or so, Wehrli said. So the "effect we see is transient," he said. 

Extrapolating a bit, "one could argue" that if someone keeps on vaping all day, every day over years, the body doesn't have time to revert to baseline — and vaping might lead to disease, Wehrli  said. But future studies that follow people for many years will be needed to prove this, he added.

"This well-done paper adds to the evidence that e-cigarettes have immediate deleterious effects on blood vessels," said Stanton Glantz, a professor of medicine at the University of California, San Francisco's Center for Tobacco Control Research and Education, who was not a part of the study. "These changes are both bad in the short run but are also indicators of long-term risk for cardiovascular disease."

Dr. Michael Siegel, a professor of community health sciences at Boston University's School of Public Health, who was also not a part of the study, agrees that this study confirms that e-cigarettes, even without nicotine, cause dysfunction in the blood vessels. 

But because this effect is short-lived and completely reversible, "it should not be assumed from this research that vaping is a cause of heart disease or permanent blood vessel damage," he said. "Further research will be needed to determine whether vaping poses a risk of irreversible blood vessel injury."

The study was published today (Aug. 20) in the journal Radiology.

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Originally published on Live Science.

Drinking a bottle of wine per week may be like smoking five to 10 cigarettes in the same time period, in terms of cancer risk, according to a new study from the United Kingdom.

The study, published today (March 28) in the journal BMC Public Health, is the first to estimate the "cigarette equivalent" of alcohol, with regard to cancer risk.

The researchers found that the increase in cancer risk tied to drinking one bottle of wine per week is equivalent to smoking five cigarettes per week for men and 10 cigarettes per week for women.

The goal of the research is to better convey the cancer risks that are tied to moderate alcohol consumption, which is generally thought to be less harmful than smoking cigarettes. Indeed, studies in both the U.S. and U.K. have found that many people aren't aware of alcohol's link to cancer. For example, a 2017 survey from the American Society of Clinical Oncology found that 70 percent of Americans didn't know that drinking alcohol is a risk factor for cancer.

"Our estimation of a cigarette equivalent for alcohol provides a useful measure for communicating possible cancer risks that exploits successful historical messaging on smoking," lead study author Dr. Theresa Hydes, of the Department of Gastroenterology and Hepatology at the University Hospital Southampton NHS Foundation Trust, said in a statement. "We hope that by using cigarettes as the comparator we could communicate this message more effectively to help individuals make more informed lifestyle choices." [7 Ways Alcohol Affects Your Health]

Dr. Richard Saitz, an addiction medicine specialist and chair of the Department of Community Health Sciences at Boston University School of Public Health, said that the study's comparison makes sense.

"I think it's about time that we communicate the cancer risks of alcohol — it's really been under the radar [and] this way is a good way to do it," said Saitz, who wasn't involved with the study.

Still, the researchers stress that the study isn't saying that moderate alcohol consumption is the same thing as smoking. The study only considered cancer risk, and not the risks of other health conditions, such as heart disease. In addition, the study looked at the lifetime risk of cancer in the general population, which might differ from an individual's cancer risk from either smoking or alcohol, the authors said.

Alcohol vs. cigarettes

To put alcohol's cancer risks in perspective, the study aimed to answer the question: In terms of cancer risk, how many cigarettes are in a bottle of wine? One bottle contains about 80 grams (2.5 ounces) of pure alcohol.

The researchers used national data from the U.K. on the lifetime risk of cancer in the general population as well as previously published research on the relationship between alcohol, smoking and cancer.

They estimated that, among nonsmokers, drinking one bottle of wine per week is tied to a 1.0 percent increase in lifetime cancer risk for men; and a 1.4 percent increase in lifetime cancer risk for women. In other words, if 1,000 men and 1,000 women each drank one bottle of wine per week, about 10 extra men and 14 extra women would develop cancer at some point in their lives, the researchers said. The higher risk among women is mainly due to the link between alcohol consumption and breast cancer.

This risk was comparable to smoking five cigarettes per week for men and 10 for women.

A "known carcinogen"

"Everybody knows that cigarettes cause cancer," Saitz told Live Science. "Hearing that some amount of alcohol is the equivalent of some amount of cigarettes" in terms of cancer risk, is helpful for the general public, he said.

Saitz noted that there's been little discussion of the cancer risks tied to alcohol, even though alcohol is a known carcinogen. Even dietary guidelines discuss the recommended number of alcoholic drinks per day.

"If I didn't call it alcohol or wine or beer or cocktails, and I just called it a carcinogen, no one would be talking about how many glasses of a carcinogen you could have," Saitz said.

The study authors noted that because the study only considered cancer risk, it didn't take into account other diseases tied to smoking or alcohol use, such as respiratory, cardiovascular or liver diseases.

The authors also pointed out that smokers typically consume far more than five to 10 cigarettes per week — the average smoker in the U.K. consumes around 80 cigarettes per week, and the average smoker in the U.S. consumes around 100 cigarettes per week.

Still, "these findings highlight moderate levels of drinking as an important public health issue," the authors concluded.

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Originally published on Live Science.

Electronic cigarettes are often thought of as "healthier" than conventional cigarettes, but the jury's still out on their potential health risks. Now, a new study has found a link between e-cigarette use and an increased risk of stroke and heart attacks.

The study analyzed information from about 400,000 Americans who took part in a national health survey in 2016. Of these, about 66,800 reported that they regularly used e-cigarettes.

Compared with non-e-cigarette users, regular users had about a 70 percent higher risk of stroke, a 60 percent higher risk of heart attack or angina (chest pain) and a 40 percent higher risk of coronary heart disease.

About 79 percent of e-cigarette users also reported using conventional cigarettes, compared with just 37 percent of non-e-cigarette users. [4 Myths About E-Cigarettes]

But the findings linking e-cigarettes with an increased risk of stroke, heart attack and coronary heart disease held even after the researchers took into account whether people were also conventional cigarette smokers, said study lead author Dr. Paul Ndunda, an assistant professor at the University of Kansas School of Medicine.

What's more, when the researchers analyzed a subset of participants who reported smoking fewer than 100 conventional cigarettes in their lives (meaning they were not regular users of cigarettes), they found that e-cigarette users were still 29 percent more likely to report having a stroke, 25 percent more likely to report having a heart attack and 18 percent more likely to report having coronary heart disease, Ndunda told Live Science.

The findings will be presented next week at American Stroke Association's International Stroke Conference 2019 in Honolulu, but has not been published in a peer-reviewed journal.

The new finding is "quite concerning," said Dr. Larry Goldstein, co-director of the Kentucky Neuroscience Institute at the University of Kentucky, who was not involved with the study. "This is the first real data that we're seeing associating e-cigarette use with hard cardiovascular events" like heart attacks and strokes, Goldstein said in a video interview with the American Stroke Association, which is a division of the American Heart Association (AHA). However, Goldstein noted that the study had limitations. For example, the researchers weren't able to take into account some factors that are known to increase people's risk of stroke and heart disease, such as high blood pressure, alcohol use and an unhealthy diet.

In addition, because the study only examined people's responses at one point in time, it is not able to tease out cause and effect — that is, it cannot prove that e-cigarette use was the cause of people's cardiovascular problems, or whether people who use e-cigarettes have other characteristics that increased their risk.

Still, Goldstein said that these early findings need to be taken seriously, especially given the relatively large percentage of young people who use e-cigarettes. In 2016, about 11 percent of U.S. high school students reported using e-cigarettes in the last 30 days.

Unlike conventional cigarettes, which heat and burn tobacco, e-cigarettes heat up and vaporize a liquid, which usually contains nicotine and other flavorings.

The AHA cautions against the use of e-cigarettes, saying that they may pose health risks that scientists do not yet fully understand. And since e-cigarettes usually contain nicotine, they may get people addicted to the substance, according to the AHA.

Some previous studies have also suggested that the flavorings in e-cigarettes themselves may be harmful. A study published last year in the journal Arteriosclerosis, Thrombosis and Vascular Biology found that e-cigarette chemical flavorings had harmful effects on blood vessel cells in a lab dish.

• Kick the Habit: 10 Scientific Quit-Smoking Tips
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Originally published on Live Science.

Strange Connections

We all know the basics about trying to avoid cancer: Don't smoke, slather on the sunscreen. And you can avoid a few other risk factors for cancer by doing things like skipping the red meat, getting vaccinated against HPV and steering clear of air pollution if at all possible.

But some things that may raise people's risk of cancer get a lot less attention. The National Cancer Institute estimates that 1.7 million people in the U.S. will be diagnosed with cancer in 2018 and that about 38 percent of people in the U.S. will get cancer during their lifetimes. Here's a look at seven strange things that may raise your risk of cancer — plus one thing you probably don't need to worry about.

Hot tea

Sipping tea may sound like a healthy way to cope with stress, and drinking green tea may even reduce cancer risk. But make sure to let your cup cool down first. Drinking tea that is extremely hot may increase the risk of cancer of the esophagus, according to a 2018 study done in China.

The study included about 450,000 people, and the researchers found that the people who said they usually drank tea that was "burning hot" and also smoked tobacco and drank alcohol excessively had a five times greater risk of esophageal cancer than people who did none of those three things. The extreme heat of the tea could damage the lining of the esophagus, increasing the damage done by smoke and alcohol, the researchers said.

Sitting still

One way to reduce the risk of cancer is to get moving. Higher levels of physical activity are linked with a reduced risk of some of the most common cancers, including lung, colon and breast cancers. One study found that exercise lowers the risk of getting any type of cancer by 7 percent. It's not clear exactly how exercise lowers people's risk of cancer, the researchers noted.

Yet it seems that many people are unaware of the link between exercise and reduced risk of cancer: A 2018 study found that only 3 percent of U.S. adults surveyed listed that risk reduction as one of the benefits of exercise. Increasing public awareness of the link could be a goal of public health efforts to reduce cancer rates, the researchers said.

Being tall

Taller people are more likely to get cancer than shorter people. A 2018 study found that for every extra 10 centimeters (4 inches) of height, a person's risk of cancer increases by 10 percent. Scientists discovered the link between height and cancer in the 1950s, the researchers said, and although it's not clear exactly how being taller may influence a person's cancer risk, it could be the simple fact that taller people have more cells in their bodies and therefore more cells that could become cancerous, the researchers said.

An earlier study found a 13 percent increase in postmenopausal women's risk of cancer with every extra 4 inches of height. And, interestingly, a 2016 study found a link between longer legs and people's risk of colon cancer. It could be that the level of growth factors in the body play a role in the link, the researchers of the colon cancer study said.

Smoke from the grill

Summer cookouts aren't as innocent as they may look. People who sit close to a grill may absorb an increased amount of chemicals called polycyclic aromatic hydrocarbons (PAHs) through their skin, a 2018 study found. Those chemicals are released by the burning of wood or charcoal and are known to be carcinogens, or cancer-causing agents.

The researchers noted that the level of PAHs that people absorbed through their skin was less than the level they were exposed to by eating the grilled meat. But still, people picked up higher levels of PAHs through their skin than they did by breathing in the smoke. It may help a bit to cover up when grilling, the researchers concluded. People's clothing may lower the level of PAHs that are absorbed through the skin over the short term.

Breast implants

Women with a certain type of breast implant may face an increased risk of a rare type of lymphoma called anaplastic large cell lymphoma (ALCL), a 2018 study found. This type of cancer is not a breast cancer; lymphomas are cancers that arise from the cells of the immune system. Among the women in the study, those who had breast implants that were textured, rather than smooth-surfaced, were at a higher risk of ALCL, the researchers said.

Still, the general risk of this cancer even among women with implants is very low. The researchers calculated that for every 7,000 women who get breast implants, 1 will go on to develop ALCL in the breast by the time she is 75. Although the reason for the link is not exactly clear, it is possible that the implants trigger increased inflammation in the breast tissue, which could lead to cancer over time, the researchers said.

Alcohol

Raising a glass and toasting to good health may not be a great idea. Researchers estimate that 5 percent of annual new cancer cases worldwide and 6 percent of yearly cancer deaths are directly due to drinking alcohol, according to a 2018 statement from the cancer doctors' group, the American Society of Clinical Oncology. Alcohol is linked to increased risks of breast, colorectal, esophageal and liver cancers, as well as cancers of the mouth and throat. And although heavier drinking is generally linked with a higher cancer risk, research shows that drinking even light or moderate amounts of alcohol may increase people's risk of cancer.

Researchers recently found evidence supporting one idea for how alcohol contributes to cancer risk. A 2018 study in mice found that the breakdown of alcohol in the body may release a chemical that damages the DNA of the stem cells of the blood, which could lead to cancer.

Too much weight

Having a higher body weight may increase the risk of more than a dozen types of cancer, a 2017 study found. People in the study who were overweight or obese faced nearly double the risk of cancers of the esophagus, stomach, liver and kidney compared with people who were in the normal weight range.

People who are overweight or obese may harbor higher levels levels of inflammation, thus increasing their cancer risk, the report said. Or, higher levels of hormones that are linked to cell growth may be behind the increased risk, the researchers said.

A 2017 study found that people who maintained a healthy lifestyle, including a lower body weight, had a lower risk of cancer than those with a less healthy lifestyle.

1 thing that probably doesn't cause cancer

Still, if it seems that everywhere you turn, you find something that may cause cancer, take comfort in this: Research suggests there's no link between the electromagnetic signals from cellphones and people's risk of cancer.

In a 10-year study published in 2018, researchers looked at the effects of very high levels of radio-frequency radiation on cancer rates in lab rats. They concluded that there is no evidence that the levels of radio-frequency radiation that people are exposed to when they use cellphones are harmful to human health.

What are your thoughts on marijuana?

If you're like the majority of Americans, you probably think this flowering herb has significant benefits and few serious risks, even though there is very little scientific evidence to support this view. That's according to a new study, published today (July 23) in the journal Annals of Internal Medicine, which surveyed people in the U.S. about their beliefs regarding the drug.

Marijuana's reputation for being a holistic and benign way to self-medicate has grown in recent years, said lead study author Dr. Salomeh Keyhani, a physician and professor of medicine at the University of California, San Francisco. A couple of years ago, Keyhani came across articles online that touted dozens of health benefits for marijuana, but they were all unfamiliar to her. "I'm a physician, and I didn't know about any of these benefits," she said. "I hadn't seen the evidence."

Keyhani and her colleagues wondered about the effects of marketing marijuana as a beneficial drug. Had this caused the U.S. public to view the substance favorably, even though very few studies examine the full effects of its use? To better understand the public's view, the researchers created an online survey that more than 9,000 people from all over the country answered. [Image Gallery: 7 Potent Medicinal Plants]

Overall, the researchers found that 81 percent of U.S. adults believe that marijuana has at least one benefit. The most common benefit named was pain management, followed by treatment of diseases such as epilepsy and relief from anxiety, stress and depression. (They're right on one of those, at least: The FDA recently approved the first marijuana-derived drug as a treatment for two severe types of epilepsy.) A larger proportion of U.S. adults, 91 percent, said they believe marijuana has at least one risk. The most common one was legal problems, followed by addiction and then impaired memory.

What concerned the researchers most about these results was the public's view of marijuana as having little health risk and significant health benefit, Keyhani told Live Science. (Legal risks were more concerning to the people in the survey than health risks.)

"The bottom line is that there's no evidence for the vast majority of this," she said. "There's limited data on harm, and people think that means it's OK."

Keyhani said she thinks the widespread commercialization of the drug has largely contributed to the increasingly favorable opinion of it in the U.S. "I think there's massive amounts of money involved in the industry right now, and just like [with] any other business, there's advertising," Keyhani said.

The researchers said they hope consumers will strive to educate themselves about marijuana use and avoid making assumptions based on biased marketing efforts. "Absence of evidence does not mean evidence of absence," Keyhani warned. "Buyer beware."

Original article on Live Science.

Changes could be coming to cigarettes in the U.S.: The Food and Drug Administration (FDA) announced today (March 15) that it is taking steps to lower nicotine levels in cigarettes. But exactly how do you take the nicotine out of tobacco?

The agency plans to propose a new rule that would limit nicotine levels in tobacco, with an ultimate goal of lowering the amount of the compound to nonaddictive levels, FDA Commissioner Dr. Scott Gottlieb said in a statement. Currently, the FDA is seeking public comment, and additional data, on how to go about developing such a rule.

"This new regulatory step … could help avoid millions of tobacco-related deaths across the country," Gottlieb said.

Although people may think of "nicotine" and "tobacco" as synonymous, there are indeed ways to separate one from the other. [Kick the Habit: 10 Scientific Quit-Smoking Tips]

What the FDA is proposing is called a low-nicotine-content cigarette, in which the actual amount of nicotine in the product is capped at a certain amount, said Andrew Strasser, an associate professor of behavioral health in psychiatry at the University of Pennsylvania Perelman School of Medicine.

One way to do this is through genetic engineering. This means that scientists would modify genes in the tobacco plant so that those that control nicotine production are shut down, Strasser told Live Science. The resulting tobacco wouldn't have any nicotine, and this tobacco could be combined with regular tobacco to create low-nicotine cigarettes.

Such low-nicotine-content cigarettes already exist for research purposes. And there have been commercial versions — a company called Vector Tobacco produced a low-nicotine-content cigarette called Quest from 2002 to 2010, according to Forbes.

But these products shouldn't be confused with so-called "light" cigarettes. With light cigarettes, the design of the cigarette is altered in a way that could, in theory, deliver lower amounts of nicotine if they were used in a specific way, said William Shadel, associate director of the Population Health Program at Rand Corp. For example, these products had ventilation holes to dilute the tobacco smoke with air. But these products still have the same amount of nicotine as regular cigarettes. And studies have found that smokers can get large amounts of nicotine from these products by blocking the ventilation holes or by inhaling more deeply.

Smokers are "very good at getting the amount of nicotine they want from the cigarettes," Shadel said.

In contrast, cigarettes made with tobacco that is genetically engineered to have a low nicotine content cannot be manipulated in this way. With these cigarettes, "more vigorous puffing is not rewarded more nicotine," Strasser said.

So could these cigarettes actually work to reduce nicotine addiction and prevent tobacco-related deaths? More research is needed to answer that question, but Strasser and Shadel agreed that early research is promising.

For example, a 2015 study published in The New England Journal of Medicine found that smokers who were assigned to use cigarettes with low nicotine content (between 0.4 and 2.4 milligrams of nicotine per gram of tobacco) smoked fewer cigarettes per day, and were less dependent on nicotine, than those who used regular cigarettes (with 15.8 milligrams of nicotine per gram of tobacco). In a 2016 study, Strasser and his colleagues similarly found that low-nicotine cigarettes were associated with reduced smoking.

"This move is very exciting and very encouraging for our field," Strasser said of the FDA announcement.

Researchers still need to examine exactly how much nicotine should be in a cigarette to reduce nicotine dependence, Shadel said. And there's still the question of whether such a rule should be implemented immediately or gradually.

"Do you rip the Band-Aid off slowly or quickly?" Strasser said. "How quickly do you move to reach the new standard of nicotine content?"

Original article on Live Science.

People vape, or smoke electronic cigarettes, for various reasons, including to quit smoking regular cigarettes and even to boost their social image. Live Science keeps you up to date on all the research findings linked to vaping, answering questions about why people vape, how vaping affects the body and more.

A word of caution to tea lovers: Let your cuppa cool a bit before taking a sip. A new study from China finds that drinking tea at extremely high temperatures may increase a person's risk of esophageal cancer, especially if that person also consumes too much alcohol and is a smoker.

Researchers found that people in China who consumed scalding tea — and also smoked tobacco and drank excessive amounts of alcohol — had a five times greater risk of esophageal cancer than people who had none of these three habits, according to the findings. [10 Do's and Don'ts to Reduce Your Risk of Cancer]

China has one of the highest rates of esophageal cancer in the world, according to the study, publishedtoday (Feb. 5) in the journal Annals of Internal Medicine.

In particular, the researchers found that drinking very hot tea, along with smoking and drinking alcohol, was linked to an increased risk of squamous cell carcinoma of the esophagus. Squamous cells line the esophagus, and this type of cancer is the most common form of esophageal cancer in the U.S., according to the American Cancer Society (ACS).

But how might hot tea raise a person's risk of esophageal cancer? Although the exact mechanism is not known, research has suggested that frequently consuming scalding liquids may result in long-term injury to the cells lining the esophagus, said lead study author Dr. Jun Lv, an epidemiologist at Peking University Health Science Center in Beijing. Indeed, frequently drinking very hot liquids, prepared at temperatures of 149 degrees Fahrenheit (65 degrees Celsius) — which is much hotter than a typical cup of coffee or tea — can increase the risk of squamous cell carcinoma of the esophagus, according to the ACS.

These heat-related changes to the esophageal lining may also increase the likelihood of damage from other risk factors for esophageal cancer, such as smoking and heavy drinking, which may damage the DNA in cells that line the esophagus, Lv told Live Science.

Tea drinkers in China

In the study, researchers looked at data from about 456,000 people in China ages 30 to 79. At the beginning of the study, the people completed a lifestyle questionnaire that asked how frequently they consumed tea, how much they consumed, how they prepared the beverage and which type of tea they drank. The participants were also asked whether the usual temperature of their tea was room temperature or warm, hot or burning hot. [4 Awesome Perks of Drinking Tea]

Though the researchers found a fivefold increased risk of esophageal cancer for people who drank scalding tea, drank large amounts of alcohol and smoked tobacco compared with people who didn't do these things, not all tea drinkers need to avoid a steaming-hot cup, according to the study. The new study found that daily hot-tea consumption — even if it was served burning hot — was not associated with an increased risk of esophageal cancer in people who were not smokers and did not drink alcohol heavily, Lv said.

But for people who drink too much alcohol or smoke tobacco, avoiding very hot tea might be beneficial for preventing esophageal cancer, Lv said.

Lv noted that the findings might apply to people in countries other than China as long as these individuals had lifestyle habits that included smoking and drinking alcohol excessively, as well as consuming scalding beverages and foods. But the most important ways to prevent esophageal cancer are to avoid tobacco and excessive alcohol use, she added.

One limitation of the study is that it relied on self-reported information from participants about their hot beverages and not on actual measurements of tea temperatures, the researchers wrote. It's also possible that consuming other types of scalding beverages and foods may have contributed to the results observed, the researchers said. In other words, tea might not have been the only hot culprit.

However, the findings should not cause tea lovers to give up the hot beverage, which has many health benefits. Most people in the U.S. typically drink their tea — and coffee — at a temperature that seems unlikely to cause esophageal cancer, according to an editorial by two cancer researchers that was published alongside the study in the same journal.

But for fans of piping-hot beverages, it may be a good idea "to wait for the liquid to cool a bit first," the editorial suggests.

Originally published on Live Science.

A new tobacco device by Philip Morris, known as IQOS, shouldn't go to market with the claim that it reduces disease risk compared with traditional cigarettes, a panel for the U.S. Food and Drug Administration (FDA) concluded today (Jan. 25), according to news reports.

But how exactly do these products work, and why did the FDA make this call?

The IQOS is a type of "heat-not-burn" tobacco product. These products could be thought of as "in the middle between [traditional] cigarettes and vaping products," said William Shadel, associate director of the Population Health Program at Rand Corp., a nonprofit research organization.

The devices use disposable tobacco "sticks" that are heated to give off an aerosol, but do not burn. Specifically, these tobacco sticks contain processed tobacco along with a few other components, including water, glycerin and cellulose fibers, according to Philip Morris. The sticks are placed into a holder, which heats the tobacco through an electronically controlled "heating blade," the company said.

The tobacco is heated up to a temperature of 662 degrees Fahrenheit (350 degrees Celsius), which is enough to create an aerosol, but not enough to burn it. (Tobacco in traditional cigarettes burns at a temperature of about 1,110 degrees Fahrenheit [600 degrees C], according to Philip Morris.) The product also comes with a charger to recharge the electronic holder. [10 Tips to Help You Quit Smoking]

Heat-not-burn products are different from electronic cigarettes (e-cigarettes), because the latter heat up and vaporize a liquid, which usually contains nicotine, Shadel said, while the former heats actual tobacco.

Philip Morris claims that, because IQOS doesn't burn the tobacco, the product releases much lower levels of the harmful chemicals typically found in tobacco smoke. The company wants to sell the product with the claim that using the products reduces the risk of tobacco-related disease, compared with using traditional cigarettes.

But the FDA panel voted to reject this claim, saying that the company hadn't provided enough evidence to show that its product lowers disease risk compared with cigarettes, according to Reuters. The panel did, however, endorse the claim that the product releases lower levels of toxic chemicals compared with traditional cigarettes.

Shadel said that this conclusion "seems about right based on the evidence available so far."

In theory, heat-and-burn products could be safer because they don't lead to the combustion of tobacco, Shadel said. But "there’s just not enough evidence that users will incur less risk" from using the products, Shadel told Live Science.

Shadel noted that most of the studies on IQOS have been conducted by Philip Morris, and much more research is needed by independent researchers who are not associated with the company to determine the safety of the product.

In addition, it's "unclear whether or not enough smokers would actually switch to these products" to have a public health benefit, Shadel said.

The panel's conclusion is just a recommendation, and in the coming months the FDA will make a final decision on whether Philip Morris can sell IQOS in the United States, and what claims the company will be able to make about the device, according to Reuters. The product is already available in 29 countries, according to Philip Morris.

Original article on Live Science.

Teen use of many drugs is on the decline, but U.S. officials remain concerned about teen marijuana use — which actually increased in the past year — and vaping, which is common, according to a new survey.

The government-backed annual survey, called Monitoring the Future, gathered data from more than 43,000 U.S. students in the eighth, 10th and 12th grades.

This year's findings included a slight increase in the rate of teen marijuana use: for all three grades combined, nearly 24 percent of the students surveyed reported using marijuana in the past year, up from 22.6 percent in 2016. But rates of teen marijuana use in 2017 are about the same as they were in 2015 — meaning that overall, rates have remained stable in recent years.

Part of the reason for this year's increase in teen marijuana use may be that today's teens perceive the drug as less risky than they did a generation ago, the researchers said. In 2017, just 29 percent of high school seniors said there was a "great risk" of harm in using marijuana regularly, down from 78 percent in 1991.

"Historically, marijuana use has gone up as adolescents see less risk of harm in using it," Richard Miech, principal investigator of the survey and a professor at the University of Michigan, said in a statement. "We’ve found that the risk adolescents see in marijuana use has been steadily going down for years to the point that it is now at the lowest level we’ve seen in four decades." [7 Ways Marijuana May Affect the Brain]

Dr. Nora Volkow, director of the National Institute on Drug Abuse (NIDA), said marijuana use among teens is concerning, in part because of its effect on education. Teens "are in school and they are supposed to be learning," Volkow said in a news conference today (Dec. 14). But regular marijuana use has been linked with poorer educational outcomes, such as a reduced chance of graduating, according to NIDA.

The survey also found that use of electronic vaporizers, or "vaping," is popular among teens. Nearly 1 in 3 high school seniors (28 percent) said they used some kind of vaping device in the past year. And when asked what they were vaping, 52 percent said "just flavorings," 33 percent said "nicotine" and 11 percent said "marijuana" or "hash oil," the survey found. (However, some research suggests that many teens may not actually know what is in their vaping device, according to NIDA.)

For the first time, the survey also asked the teens in the study about vaping specific substances in the past month. It found that, among high school seniors, about 17 percent of the participants reported vaping of any kind in the past month, 11 percent reported vaping nicotine, 10 percent reported vaping just flavoring and 5 percent reported vaping marijuana.

"We are especially concerned because the survey shows that some of the teens using these devices are first-time nicotine users," Volkow said. "Recent research suggests that some of them could move on to regular cigarette smoking, so it is critical that we intervene with evidence-based efforts to prevent youth from using these products."

But there is good news from the survey, the researchers said. Use of illegal drugs other than marijuana and inhalants (which include sniffing glue, gases or sprays) was at its lowest level in the history of the survey, which dates back to 1975. And despite high rates of opioid use among adults, rates of opioid use among teens continue to decline.

"The reductions [in opioid use] have been quite dramatic," Volkow said. For example, in 2017, just 2 percent of high school seniors reported misusing the opioid pain reliever Vicodin in the past year, down from 10.5 percent in 2003. And rates of heroin use among teens remain low, with just 0.4 percent of high school seniors, 0.2 percent of 10th graders and 0.3 percent of eighth graders reporting use of the drug in the past year.

The survey also found:

• Rates of teen use of hookahs are declining. In 2017, 10 percent of high school seniors reported using a hookah in the past year, down from 13 percent last year and 23 percent in 2010.
• Rates of teen use of traditional cigarettes continue to decline. For all three grades combined, all measures of cigarette use (including lifetime use, past month use and daily use) are at historic lows since they were first measured in 1991. For example, just 10 percent of 12th graders reported using cigarettes in the past month, meaning that rates of cigarette use are now lower than rates of marijuana use. (About 23 percent of 12th graders said they used marijuana in the past month.)
• Rates of teen use of alcohol have been declining for many years, but in 2017, rates of alcohol use were about the same as the year before. This could herald an end to the long-term declines in teen use of alcohol, the researchers said.

Despite declines in teen use of many drugs, the researchers said that people should not be complacent about tackling teen drug use, as every new generation is vulnerable. "They don’t know about why they shouldn’t use drugs any more than they know how to read, unless we teach them again," said Lloyd Johnston, a professor at the University of Michigan and previous director of the survey, during the press conference.

Original article on Live Science.

Switching to e-cigarettes won't solve all the health problems smokers face. For example, e-cigarettes are still addictive, and studies suggest that they may be bad for heart health. But compared with traditional tobacco cigarettes — which, in addition to nicotine, are full of tar and other toxins — e-cigarettes could be a less-risky option, a new study suggests.

Using mathematical models, researchers calculated how two possible scenarios of cigarette and e-cigarette use — one optimistic scenario and one pessimistic scenario — could impact public health if Americans who smoked cigarettes switched to e-cigarettes over the next 10 years.

The researchers noted that the study had several limitations. For example, the models are based on smoking uptake and quitting rates through 2012, but they do not account for the recent growth in e-cigarette use. In addition, the models included only cigarettes and e-cigarettes, and excluded other tobacco products, such as smokeless tobacco, according to the study. [4 Myths About E-Cigarettes]

The optimistic and pessimistic scenarios were based on a status-quo rate up to 2012 of smokers either quitting smoking altogether or switching to vaping. In the study's "optimistic" model, the researchers assumed that more people stopped smoking tobacco cigarettes (primarily switching to e-cigarettes) and that the current scientific understanding that e-cigs aren't quite as bad as cigarettes holds true. In that optimistic model, the researchers found that 6.6 million premature deaths could be avoided in the U.S., according to the study, which was published yesterday (Oct. 2) in the journal Tobacco Control.

Though one of the study authors has worked with both Pfizer and Johnson & Johnson, two manufacturers of smoking-cessation medications, this particular study was funded by the National Institutes of Health and did not receive any industry money, according to a statement.

In the study's "pessimistic" model, the researchers assumed that fewer people gave up smoking than are doing so under the current rate and that the health risks of e-cigarettes turned out to be worse than scientists' current understanding. In this case, only 1.6 million premature deaths were avoided.

The findings "support a policy strategy that encourages replacing cigarette smoking with vaping to yield substantial life-year gains" compared with cigarette smoking, lead researcher David Levy, an oncologist at Georgetown University Medical Center, said in a statement. In other words, switching from cigarettes to e-cigarettes could extend the lives of smokers, compared with if they were to continue smoking traditional tobacco cigarettes. [10 Tips to Help You Quit Smoking]

In addition to living longer than they would if they continued smoking tobacco cigarettes, those who switched to e-cigarettes might see other health benefits, "including reduced disease disability to smokers, reduced pain and suffering, and reduced exposure to secondhand smoke," Levy said.

"Even the gloomiest analysis [the pessimistic model] shows a significant gain in years of life if nicotine is obtained from vaping instead of much more deadly amounts of toxicants inhaled with cigarette smoke," Levy said.

Writing in an editorial that was published alongside the new study, Marita Hefler, a public health researcher at Menzies School of Health Research in Australia, said that "the health gains modelled [in the new study] show that even in a pessimistic scenario," rapidly phasing out regular cigarettes could result in significant public health gains.

Original article on Live Science.

One of the most well-known purported uses for medical marijuana is to alleviate symptoms related to cancer treatment, and a new study finds that use of the drug among cancer patients is not uncommon.

In the study, which included more than 900 cancer patients in Seattle, nearly one-quarter reported using medical marijuana in the past year. In addition, almost all the participants said they wanted to learn more about medical marijuana, according to the study, published today (Sept. 25) in the journal Cancer.

But existing research on marijuana's effects on cancer-related symptoms is limited, the researchers said. Indeed, the study underscores the need for more research into the risks and benefits of marijuana use among cancer patients, lead study author Dr. Steven Pergam, a researcher at the Fred Hutchinson Cancer Research Center in Seattle, said in a statement.

Cancer patients want information about marijuana use during their treatment, but they aren't getting this information from their doctors, Pergam said. Because of this, patients instead seek information from "alternate, nonscientific sources," he said. [Marijuana Could Treat These 5 Conditions]

In the study, the researchers surveyed cancer patients at the Seattle Cancer Care Alliance, a cancer treatment center. The survey included questions about marijuana use among cancer patients, as well as questions about the patients' beliefs surrounding the drug.

The researchers found that 24 percent of the patients in the study were "active users," meaning that they had used marijuana in the past year for cancer-related symptoms, and 21 percent reported using the drug in the past month. These rates are more than double those reported in national surveys of any type of marijuana user, the researchers said.

Among the active users, the researchers found that 74 percent reported using marijuana at least once a week, 56 reported using the drug at least once a day and 31 percent reported using the drug multiple times a day. Smoking and consuming edibles were the most common ways of using the drug, the researchers found.

Three-quarters of the active users said they used the drug to help with physical symptoms, including pain and nausea, and two-thirds reported that they used marijuana to help with psychiatric symptoms, including stress and sleep problems.

Active users were more likely than people who never used the drug to cite legalization as a reason for using marijuana, the researchers found. Active users were also younger than those who didn't use the drug or who had used the drug in the past but quit, according to the study.

And though 74 percent of the people in the study said that they would like information on medical marijuana from their cancer teams, less than 15 percent actually received information from their health care providers. Instead, most people sought out information from friends, family members, media sources or other cancer patients, the researchers found.

The researchers noted that the study had limitations. For example, it's possible that the people who completed the survey were more likely to have an interest in medical marijuana, the researchers said. In addition, because the study was carried out at only one cancer-treatment center and in a state where recreational marijuana use is legal, the findings may not apply to people across the country, the researchers said.

Originally published on Live Science.

Marijuana's popularity among American adults is on the rise — and use of the recreational drug is expected to continue to increase, according to several surveys.

The increase in popularity, along with more permissive attitudes toward marijuana use, may be due in part to its changing legalization status in many parts of the country, experts say. 

Forty-five percent of adults in the U.S. have used marijuana at least once in their lives, according to a Gallup poll released in mid-July — the all-time highest percentage in the 48-year history of Gallup asking Americans this question. [25 Odd Facts About Marijuana]

Trying marijuana at least once as an adult isn't the same as being a user of the drug, but the percentage of current smokers is on the rise as well: The same Gallup poll revealed that 12 percent of U.S. adults — 1 in 8 — said they use marijuana, up from 7 percent in 2013. 

Meanwhile, data from two large national surveys done by the federal government also finds increasing rates of marijuana use among adults. (Gallup does its poll by telephone interviews, while federal surveys conduct face-to-face interviews. An in-person interview could possibly influence results because marijuana is still illegal in most states and people may be hesitant to admit they use it.)

One of these large surveys, published in 2015 in JAMA Psychiatry, found that the prevalence of marijuana use in the United States more than doubled over a decade. After interviewing about 36,000 people, ages 18 and older, the researchers found that the percentage of adults who reported using marijuana in the past year jumped from 4.1 percent in 2001–2002 to 9.5 percent in 2012-2013.

The data showed that marijuana use was increasing in males and females in many age groups, although it was increasing a little faster in young adults, ages 18 to 29, and in males, said Deborah Hasin, one of the study authors and a professor of epidemiology at Columbia University's Mailman School of Public Health in New York City. The rates of use were also increasing among middle-age and older adults, she said.

But the trends in increasing use appear to be limited to adults: Marijuana use is not increasing among teenagers, Hasin said. Two major studies have shown that marijuana use has been relatively stable in adolescents over the last few years, she said.  

Popularity explained

The top four reasons people give for using marijuana are to relax, to relieve pain, to have fun and to help them be social, according to a survey by Yahoo News/Marist College done in March.Unwinding and fitting in may explain why many people decide to smoke pot, but what are some reasons for its rising popularity among adults?

One explanation is the growing perception that marijuana has few risks, Hasin told Live Science. In the 1960s and '70s, scare tactics were used to discourage young people from smoking pot, and there was a perception that marijuana could lead to a person becoming addicted to heroin, she said.

These days, teens and adults increasingly see marijuana as a natural substance that's basically safe, Hasin said. However, one of the known risks of immediate use of the drug is impaired driving ability, she said.

Many people probably consider smoking marijuana as less likely to lead to drug dependence than using other illegal substances. But many of the studies that concluded marijuana may be less addictive than other drugs were done 25 years ago when marijuana was less potent than it is now, Hasin said.

And not only are tetrahydrocannabinol (THC) concentrations, marijuana's main psychoactive ingredient, higher now than in the past, but people may be using these more potent forms in different ways, such as vaping or consuming them as edibles. Researchers don't truly know yet how higherpotencies and newer delivery methods will affect marijuana use disorders, Hasin said.

The changing legal status of marijuana in many states may also be responsible for shifting attitudes toward its use and perceived dangers. Twenty-nine states have passed medical marijuana laws, and voters in eight states have approved limited recreational use in adults, Hasin said. [3 More States Legalize Recreational Use of Marijuana: How the Map Looks Now]

There is some evidence from states that have passed medical marijuana laws that shows faster increases in overall marijuana use in adults, compared with states without medical marijuana laws, Hasin said.

Data from California and Colorado, two early adopters of medical marijuana laws, has shown that increased availability of marijuana has led to more overall acceptability of marijuana use, in general, as well increasing perceptions of the drug's safety, Hasin said. All of these factors seem to increase recreational use of marijuana by adults within these two states, she said.

Brain effects

Marijuana's popularity can also be explained by a simpler factor: Many people find the drug enjoyable to use. [7 Ways Marijuana May Affect the Brain]

When a person gets high, marijuana has the same effect on the release of the brain chemical dopamine as other psychoactive substances, such as cocaine or heroin, said Francesca Filbey, the director of Cognitive Neuroscience Research in Addictive Disorders at the Center for BrainHealth at the University of Texas at Dallas.

THC binds to cannabinoid receptors, which are found all over the brain, Filbey told Live Science. When THC binds to the receptors, it stimulates the increased release of dopamine, which activates the brain's reward system and contributes to marijuana's pleasurable effects, she said. 

But marijuana doesn't only affect areas of the brain involved in feeling good. THC can also attach to receptors in the brain that play a role in modulating other types of behavior, Filbey said. It works like volume control, "turning down" areas of the brain that influence memory, concentration, decision-making, movement and pain perception, she said. 

Originally published on Live Science.

Smoking pot is often considered safer than smoking cigarettes, but a new study suggests that marijuana use may increase a person's risk of death from high blood pressure.

Over the two-decade-long study period, marijuana users, whose level and frequency of smoking was not assessed in the study, had a more than threefold greater risk of dying from hypertension than nonusers. This increase in risk was greater than that associated with cigarette smoking, the researchers said.

"Support for liberal marijuana use is partly due to claims that it is beneficial, and possibly not harmful, to health," lead study author Barbara Yankey, a doctoral student of epidemiology and biostatistics at Georgia State University, said in a statement. "However, there is little research on the impact of marijuana use on cardiovascular and [stroke] mortality." [25 Odd Facts About Marijuana]

The risks associated with smoking cigarettes, on the other hand, are well established, according to the study, published today (Aug. 9) in the European Journal of Preventive Cardiology. Studies linking heart disease deaths and cigarettes, for example, are "extensive," leading the researchers to hypothesize that smoking pot would be associated with a similar level of risk.

The study included more than 1,200 adults in the U.S. who had participated in the 2005 National Health and Nutrition Examination Survey (NHANES), a federal survey done annually to evaluate Americans' diets and health. As a part of the survey, the participants were asked if they had ever used marijuana and, if so, when they first tried the drug. The survey also collected data on cigarette use.

Using data from 2011 from the National Center for Health Statistics, the researchers were able to determine if any of the participants in the NHANES study had died during the study period.

Using the two data sets, the researchers estimated the associations between marijuana use and length of use with deaths from high blood pressure, heart disease and stroke.

At the end of the study period, 73 percent of the participants were still alive, the researchers found. Nearly 35 percent of them reported that they did not use marijuana or tobacco; 21 percent used only marijuana (no tobacco); 4 percent smoked cigarettes (no marijuana); 20 percent used both marijuana and tobacco; 16 percent used marijuana currently and smoked cigarettes in the past; and about 5 percent did not use marijuana or tobacco currently but smoked cigarettes in the past.

The average duration of marijuana use was 12 years, and the average duration of cigarette use was 10 years.

The study found that, compared with people who didn't use marijuana, those who did had a 3.4-fold greater risk of death from high blood pressure during the study period. There were no statistically significant links between marijuana use and the risk of death from heart disease or stroke.

Yankey noted that the findings suggest that marijuana use "may carry even heavier consequences on the cardiovascular system than that already established for cigarette smoking," but she added that larger studies are needed to confirm the results. [Where Americans Smoke and Grow Marijuana (Maps)] 

The researchers acknowledged several limitations of the study. For example, the study assumed that marijuana use was continuous from the time the study participants said they first tried the drug, but this may not be accurate.

Even so, the new findings are "not particularly surprising" and make sense in the context of previous studies on marijuana smoking, said Dr. Charles Pollack, an emergency-medicine physician at Thomas Jefferson University Hospital in Philadelphia and the director of the university's Lambert Center for the Study of Medicinal Cannabis and Hemp. Pollack was not involved with the new study.

But the study had some weaknesses, Pollack told Live Science. For example, relying on study participants to report their marijuana use can be "unreliable and inconsistent," he said. In addition, "there are so many strains of [marijuana] out there, with no quality standards … making it tough to generalize" the effects, he added.

Pollack also noted that the study focused on recreational marijuana use, "which is different from most medicinal cannabis use." Typically, marijuana from medical dispensaries is of higher quality, Pollack said, but in both cases (recreational and medicinal), "nothing in this space is tightly controlled."

Indeed, the study authors wrote that they "are not disputing the possible medicinal benefits of standardized cannabis formulations," but added that the "recreational use of marijuana should be approached with caution."

Originally published on Live Science.

Cigarette smoke can have wide-ranging health effects on the body, and the lungs and airways are two of the hardest-hit areas.

But the good news is that after a person quits smoking, the lungs can heal to a certain extent, said Dr. Norman Edelman, a senior scientific advisor for the American Lung Association and a specialist in pulmonary medicine.

As soon as a person inhales the chemicals found in cigarette smoke, the lung's delicate lining becomes inflamed and irritated. For several hours after the individual smoked, the tiny hairs called cilia that line the lungs slow down their brush-like movement. This causes them to become temporarily paralyzed and less effective at cleaning out mucus and other substances, such as dust particles, from the airways.  

Another change observed in the lungs of smokers is an increase in the thickness and production of mucus. Because cilia cannot sweep mucus out of the lungs as quickly as it's being formed, it accumulates in the airways, clogs them up and triggers a cough. A buildup of mucus can also cause more lung infections, such as chronic bronchitis. [Kick the Habit: 10 Scientific Quit-Smoking Tips]

How lungs heal

Generally speaking, some of the short-term inflammatory changes to the lungs can be reversed when people quit smoking, Edelman said. In other words, swelling subsides on the surface of the lungs and airways, and lung cells produce less mucus, he said. New cilia can grow, and these are better at clearing out mucus secretions, he added.

In the days to weeks after quitting, former smokers will notice that they have less shortness of breath when they exercise, Edelman told Live Science. It's not exactly clear why this happens, but part of it stems from getting carbon monoxide out of the blood, he said. This gas found in cigarette smoke can interfere with the transport of oxygen, because carbon monoxide binds to red blood cells in place of oxygen. This may account for the breathlessness some smokers experience.

Another reason former smokers have improved breathing is because the inflammation decreases in the lining of their airways; this happens because the lining is no longer exposed to smoke's chemical irritants, Edelman said. This reduced swelling makes more room for air to flow through the passageways.

Paradoxically, former smokers may cough more during the first few weeks after they quit than when they were smoking. But this is a good thing; it means the lung's cilia are active again, and these fine hairs can now move excess mucus secretions from the lungs into the airways and toward the throat, where they can be coughed up, Edelman said.

"Coughing is cleaning up the gunk in the lungs," Edelman explained.

Another health benefit of quitting is a reduced risk for lung cancer, he said. The longer that former smokers go without lighting up, the lower their risk of getting this cancer, although the risk never completely goes away, Edelman said.

For example, 10 years after quitting smoking, a former smoker's odds of getting lung cancer are about half that of a smoker, according to the Centers for Disease Control and Prevention. But an ex-smoker is still more likely to die of lung cancer than someone who has never smoked.

Not all changes are reversible

The body is very good at repairing some of the damage to lung cells and tissues caused by smoking, but not all of the damage is reversible.

Damage to the lungs and a deterioration in lung function are directly related to the number of packs of cigarettes a person typically smokes per day times the number of years the person has smoked, a measure known as "pack years," Edelman said. The greater the pack years, the more likely the lungs will have irreversible damage, he noted.

Although the lungs have ways to protect themselves from damage, these defenses are reduced with long-term exposure to the harmful chemicals inhaled from cigarettes. As a result, lung tissue can become inflamed and scarred from smoking, and so the lungs lose elasticity and can no longer exchange oxygen efficiently.

Long-term smoking can lead to emphysema, a type of chronic obstructive pulmonary disease (COPD). This condition destroys a portion of the lungs known as the alveoli, which is where the exchange of oxygen and carbon dioxide takes place, Edelman said. People with COPD have shortness of breath and difficulty breathing. 

Once a person's lungs are damaged to the point of emphysema, the walls of the airways lose their shape and elasticity, making it difficult to push all the air out of the lungs. These lung changes are permanent and irreversible, Edelman said

Using MRI imaging, scientists have recently learned that the damage to airways linked with emphysema begins a few years after a person starts smoking, although symptoms of the disease may not show up until 20 to 30 years down the road, Edelman said.

But it's never too late to quit smoking, and quitting at any age can help people breathe better and increase their life expectancy, Edelman said.

Originally published on Live Science.

For young smokers, the pleasure of smoking a cigarette is greater when they are also drinking alcohol than when they are also smoking pot, according to a new study.

The findings could have implications for helping people quit smoking, the researchers said.

The researchers surveyed U.S. adults ages 18 to 25 who regularly smoked cigarettes and also used alcohol or marijuana. The participants were asked whether their pleasure from smoking cigarettes changes when they drink alcohol or when they smoke marijuana.

The participants reported that they experience an increase in the pleasure from cigarettes when using alcohol, but not when using marijuana. [25 Odd Facts About Marijuana]

The findings suggest that the reasons why people combine smoking cigarettes with drinking alcohol are different from the reasons they combine smoking cigarettes with smoking marijuana, said study co-author Johannes Thrul, a postdoctoral scholar at the University of California, San Francisco Center for Tobacco Control Research and Education.

"Targeting the increased pleasure from smoking cigarettes when drinking alcohol could enhance effectiveness of smoking cessation interventions among young adults," the researchers wrote in the April 18 issue of the journal Addiction Research & Theory.

On the other hand, the findings suggest that the participants who smoke cigarettes with marijuana are doing so for reasons other than an increase in pleasure, the researchers said. Therefore, "it may be more important to target other reasons for co-use of tobacco and marijuana," they said. For example, they may use the two substances together because the nicotine in tobacco may lessen some of the temporary effects of marijuana, including sedative effects and impairments to thinking , the researchers said.

The study found similar responses among cigarette smokers who used both alcohol and marijuana, and cigarette smokers who used only alcohol or only marijuana.

Future studies should also look at what people say they expect will happen when they use cigarettes and alcohol together, or cigarettes and marijuana together, rather than just asking about perceived pleasure, the researchers said.

Original article on Live Science.

Nearly 1 billion people around the world light up cigarettes every day, a new study finds.

The findings signal to experts that despite progress in reducing the number of smokers, more work is still needed to target tobacco use, the researchers said.

Interestingly, the researchers found that although the percentage of people who smoke has declined, the overall number of smokers has actually increased, thanks to population growth, according to the study, published April 5 in the journal The Lancet.

In other words, because there are more people on Earth, there are more smokers. But compared to the overall population, the percentage of people who smoke is lower than it was 25 years ago. [Kick the Habit: 10 Scientific Quit-Smoking Tips]

"Growth in the sheer number of daily smokers still outpaces the global decline in daily smoking rates, indicating the need to prevent more people from starting the tobacco habit and to encourage smokers to quit," senior study author Emmanuela Gakidou, a professor of global health at the Institute for Health Metrics and Evaluation at the University of Washington, said in a statement.

In the study, the researchers looked at data on smokers in 195 countries and territories between 1990 and 2015. Overall, they found that approximately 933 million people smoked each day in 2015. The world's population was 7.2 billion in 2015, up from 5.3 billion in 1990, according to U.S. Census statistics.

More than 80 percent of these daily smokers in 2015 were men, according to the study. The researchers found that worldwide, 1 in 4 men smoked every day, compared with 1 in 20 women. The daily smoking rates in men decreased from 35 percent in 1990 to 25 percent in 2015, and the daily smoking rates in women decreased from 8 percent in 1990 to 5 percent in 2015.

More than half of the male smokers in the world lived in just three countries in 2015, the researchers found. China had approximately 254 million male smokers, India had about 91 million and Indonesia had about 50 million.

Although China, India and Indonesia had the highest numbers of male smokers, it was the Pacific island nation of Kiribati that had the highest rates of male smokers, the researchers found. Nearly 50 percent of the men in Kiribati smoked on a daily basis in 2015.

The countries with the most female smokers in 2015 were the U.S. (17 million smokers), China (14 million smokers) and India (13.5 million smokers). Together, these three countries accounted for just over one-quarter of the female smokers worldwide, the researchers found.

The highest rate of female smoking in 2015 was in Greenland: The researchers found that 44 percent of the women in the Danish territory smoked daily, according to the study. 

More than 11 percent of deaths worldwide were due to smoking in 2015, according to the study, and just over half of these deaths occurred in four countries: China, India, the U.S. and Russia.

Originally published on Live Science.

WASHINGTON — The types of bacteria in your mouth may be linked to your risk of certain cancers.

By studying the links between bacteria and cancer, scientists one day hope to be able to tell a person what his or her cancer risk is based on the bacteria present in his or her body, said Jiyoung Ahn, an associate professor of epidemiology at the New York University School of Medicine. Perhaps more important, Ahn said, these bacteria and microbes, collectively called the microbiome, could give people information about what they can do to lower their risk.

Ahn presented her research about these links here today (April 2) at the American Association for Cancer Research's annual meeting. [Body Bugs: 5 Surprising Facts About Your Microbiome]

Research into the body's microbiome is relatively new, Ahn said.

In fact, only within the past five years or so have scientists recognized that 80 percent of the bacteria found in the human body can't be grown in a lab dish, Ahn told Live Science. That means that previous research that focused on growing bacteria from humans in labs provided only a small part of the picture of the human microbiome.

It was only when researchers began sequencing the DNA of the bacteria taken from people that they were able to complete the picture and identify the many missing microbes, Ahn said.

Now, scientists are starting to understand the potential links between the oral microbiome and certain cancers, Ahn said. Her research has focused on several cancers, including pancreatic cancer and esophageal cancer.

Body bugs

All people share a "core" microbiome, Ahn noted. "In this room, I bet everyone" has microbes from the same five main groups of bacteria, she said during her talk. But within these large groups, there's variability among people; for example, one person may have more bacteria from one genus than another person has, she said.

Researchers now want to know whether this variability may be linked to people's cancer risk, she said.

In Ahn's research on pancreatic cancer, her team found that people who had higher levels of one type of oral bacteria, Porphyromonas gingivalis, had a 60 percent higher risk of developing pancreatic cancer compared with people who had lower levels of these bacteria. And higher levels of another type of oral bacteria, Aggregatibacter actinomycetemcomitans, was linked to a more than doubled risk of pancreatic cancer, she said.

Pancreatic cancer is one of the deadliest cancers, in part because it's very difficult to diagnose at an early stage, Ahn said during her talk. She hopes that, in the future, doctors will be able to identify the disease by looking at a person's oral bacteria.

There are also differences in the oral microbiomes of people with esophageal cancer compared with the oral microbiomes of people who do not have the disease, Ahn said. For example, people with esophageal cancer tend to have much lower levels of a type of bacteria called Proteobacteria, she said. [5 Ways Gut Bacteria Affect Your Health]

In both cases — pancreatic cancer and esophageal cancer — more research is needed to determine if there is a cause-and-effect relationship. In other words, researchers do not know whether the differences in bacteria in a person's mouth may cause cancer or if they are a sign of some other change in the body.

But other earlier research also suggested a cancer link. Studies in animals, for example, have shown that the bacteria in the mouth can travel throughout the body, Ahn said. Other research has suggested that certain bacteria may interact with receptors on the surfaces of cells in a way that contributes to cancer, she said.

Other factors, including smoking and alcohol, also may play a role. Both smoking and drinking alcohol can change the oral microbiome, Ahn said. And indeed, both are risk factors for esophageal cancer and pancreatic cancer.

Smokers, for example, have much lower levels of Proteobacteria in their mouths compared with people who have never smoked, Ahn said. If a person quits smoking, the levels of Proteobacteria gradually increase over the years, she added.

Furthermore, studies have shown that people who have more than two drinks per day have lower levels of Lactobacillus bacteria, Ahn said. Lactobacillus bacteria are some of the "friendly" bacteria often found in probiotics.

Originally published on Live Science.

The chemical tetrahydrocannabinol (THC) in marijuana is known to trigger responses in brain regions related to thinking, perception, coordination and memory, and to have a lasting impact on users when taken frequently over time.

But much less is known about how a growing brain responds to its first introduction to marijuana. An upcoming, long-term study, however, could shed light on the ways that marijuana and other substances and experiences affect a teenager's developing brain.

Most studies on marijuana and how it affects the brain look at chronic users, so there isn't much data on people who use the drug occasionally or only once, said Susan Weiss, director of the Division of Extramural Research at the National Institute on Drug Abuse (NIDA). Researchers at NIDA, along with researchers at the National Institute on Alcohol Abuse and Alcoholism (NIAAA) and the National Cancer Institute (NCI), are leading the study.

"We don't really know what happens to a first-time user — we don't know if one use will change the brain and make you more vulnerable to taking other drugs, for example," Weiss told Live Science. [7 Ways Marijuana May Affect the Brain]

The new study, called the Adolescent Brain Cognitive Development (ABCD) Study, is a collaborative investigation funded by the National Institutes of Health (NIH). It may help scientists single out the effects on brain development of substances like marijuana, Weiss explained. It could also open a window into how the maturing brain is shaped by biological factors, such as exposure to sex hormones, and by other factors, such as exercise and social pressures, said Weiss.

The developing brain

The human brain grows throughout the teenage years and even into a person's early 20s, recent studies have shown. As a developing brain forms new structures and connections, it may be especially vulnerable to disruptions, particularly those caused by exposure to certain experiences, such as drugs and alcohol.

Recent studies have found that people who used marijuana when they were young were more likely to develop a marijuana disorder when they get older — and were also more likely to develop other substance use disorders, NIDA reported.

But it's unclear if that tendency emerged because of how marijuana affects the brain, or if marijuana use is not a causal factor but merely a red flag for a person's general risk of addiction, Weiss said. In other words, it could be that people who are more likely to try marijuana, and use it frequently, are also more likely to become dependent on substances in general.

"This is not to say that someone who starts smoking marijuana as an adult won't become addicted, but the majority of the data at this point indicates adolescence as a high-risk period for cannabis use — and particularly for regular cannabis use," she said.

Prior studies have shown that people who use marijuana often or have used it for some time show changes in the connections among their brain structures. The changes may be within the structures themselves, or in the volume of certain brain areas. This is particularly true if they used marijuana repeatedly when they were young, Weiss told Live Science.

But it's difficult to say if marijuana alone is the culprit for those brain abnormalities, she added.

"Most young people who start using marijuana when young are also using other substances, like alcohol and tobacco. We do the best we can to factor out those variables, but it's hard to disentangle those effects," Weiss explained. [Marijuana Could Treat These 5 Conditions]

A decade of observation

In the ABCD Study, researchers at 21 research centers across the U.S will follow 10,000 children, starting at age 9 or 10, over a period of 10 years. Every two years, the researchers will conduct magnetic resonance imaging (MRI) scans of the participants' brains, collect biospecimens such as saliva for genetic analysis, and evaluate the children's interview responses and performance on cognitive tests. Additional follow-ups will take place every three to six months.

By tracking the subjects' physical and behavioral trajectories over time, the study will create the first map of changes in adolescents' brains and bodies as they are shaped by both biological and social factors, ABCD said. Those factors include experimentation with tobacco, drugs and alcohol.

"We'll be looking at what is normal brain development, what sort of variability is there, what differences there are between the sexes, [and] how physical activity and substance use affect brain development," Weiss told Live Science.

"By having a very large number of participants, we hope to be able to ask a lot of these questions that right now we don't have answers to," she said.

Original article on Live Science.

The reasons people use e-cigarettes are shifting: Fewer people are using them to quit smoking, and more people are using them to boost their social image, a new study finds. 

The findings could have important implications for public health, as they could help guide initiatives seeking to discourage e-cigarette use, the researchers said.

Although scientists have previously looked at why people choose to use e-cigarettes, the researchers of the new study noted that the surveys used in past research typically limited the participants' responses. [4 Myths About E-Cigarettes]

For example, surveys may have included a series of yes-or-no questions, or multiple-choice questions, and didn't allow respondents to answer in their own words, the researchers wrote in the study, which was published today (March 1) in the journal PLOS ONE. 

"What if we could listen in to what people are naturally saying about e-cigarettes to their friends rather than [to] a surveyor?" lead study author John Ayers, a public health researcher at San Diego State University, said in a statement.

To do so, the researchers turned to Twitter.

In the 2012 to 2015 study, they analyzed more than 3 million public tweets about e-cigarettes. Tweets that were initially included in the study contained words or phrases such as "electronic cigarette," "electronic cig," e-cig," "vape" and others.

These tweets were then narrowed down to only include those referring to using e-cigs; for example, tweets such as "I have an electronic cig and it's helping me quit" were included, but tweets such as "I just saw someone vaping" were excluded.

Finally, the researchers categorized the tweets based on the person's reason for vaping. They ended up with a total of seven major reasons: low cost, flavor choices, safe to use, can use indoors, favorable odor, quitting regular cigarettes and social image.

The tweets from 2012 showed that people's most common reason for vaping was quitting smoking regular cigarettes, according to the study, with 43 percent of tweets citing this as a reason. Social image was the second most common reason, with 21 percent of tweets, and indoor use was third, with 17 percent.

By 2015, however, less than 30 percent of the tweets cited quitting smoking regular cigarettes as a reason for vaping. Rather, social image was the most common reason cited, accounting for 37 percent of the vaping-related tweets. Indoor use also decreased as a reason, dropping down to 12 percent of the tweets, the researchers found.

The researchers noted that their findings were supported by previous research and anecdotal evidence.

For example, the decrease in quitting smoking as a reason for e-cigarette use lined up with a decrease in Google searches for e-cigarettes as a way to quit smoking, according to the study. And the decrease in citing indoor use lined up with the time frame over which a number of cities and states banned e-cig use indoors, they wrote.

At the same time, e-cig marketing has increasingly focused on social image, the researchers wrote. This supports the finding that social image has increased as a reason cited for use, they said.

Originally published on Live Science.

Keeping your heart healthy could also benefit your brain, hints a new study suggesting that people who have risk factors for heart disease in middle age are also at increased risk for dementia later in life.

The study analyzed information from more than 15,000 U.S. adults who started the study when they were ages 45 to 64 and were followed for 25 years. During the study, about 1,500 participants developed dementia.

People who had diabetes or high blood pressure at the start of the study, or who smoked at that time, were at increased risk for developing dementia about 25 years later. (All three of these factors are known to increase the risk of heart disease.) [6 Big Mysteries of Alzheimer's Disease]

Specifically, those with diabetes in middle age were 77 percent more likely to develop dementia during the study, compared to those without diabetes in middle age. Those who smoked at the start of the study were 41 percent more likely to develop dementia than those who didn't smoke at the start of the study. And those who had high blood pressure were 39 percent more likely to develop dementia than those who didn't have high blood pressure.

"The health of your vascular system in midlife is really important to the health of your brain when you are older," study researcher Dr. Rebecca Gottesman, an associate professor of neurology and epidemiology at Johns Hopkins University in Baltimore, said in a statement. "If you want to protect your brain as you get older, stop smoking, watch your weight, and go to the doctor so diabetes and high blood pressure can be detected and treated," Gottesman said.

Dementia refers to a group of symptoms — such as memory loss and problems with communication — that result from changes in the brain. There are many diseases and conditions that can cause dementia, including Alzheimer's disease.

A growing body of evidence suggests that the risk of dementia is increased by conditions that damage the heart or blood vessels, such as high blood pressure, diabetes and stroke, according to the Alzheimer's Association.

The researchers note that the new study did not test whether treating heart disease risk factors actually lowers dementia risk. To take a look at exactly how these factors may increase the risk of dementia, more research is needed, the researchers said.

The study was presented today (Feb. 22) at the American Stroke Association's International Stroke Conference 2017 in Houston.

Original article on Live Science.

Smoking e-cigarettes may be bad for your heart, a small new study suggests.

The study found that certain markers for heart disease risk were higher in e-cigarette users than in nonusers. For example, e-cigarette users had higher levels of adrenaline in their hearts, compared with nonusers. They also had elevated levels of inflammation and oxidative stress (a process that can damage cells) in their bodies.

"This suggests that e-cigarettes have a more complicated effect than just the direct pharmacological effect of nicotine," said study co-author Dr. Holly Middlekauff, a cardiologist at the University of California, Los Angeles' David Geffen School of Medicine. That's because nicotine and other e-cigarette compounds "may set in motion a constellation of physiologic effects that persist, even when nicotine is out of the system," Middlekauff told Live Science. [4 Myths About E-Cigarettes]

E-cigarettes are an increasingly popular alternative to tobacco cigarettes. They produce no combustion and contain no tobacco, but deliver a heated mixture of nicotine and flavors to the mouth and lungs of the user. The medical community's reaction to e-cigarettes has been mixed, with significant controversy over whether e-cigarettes represent a "safer" alternative to tobacco cigarettes, the study said.

Because e-cigarettes do not burn tobacco, they do not produce the same toxic compounds as regular cigarettes do. Moreover, they produce very little tar or carbon monoxide, so many proponents of e-cigarettes claim that e-cigs are healthier than regular, "combustible" cigarettes, Aruni Bhatnagar, a professor of medicine at the University of Louisville, who was not involved in the study, wrote in an editorial commenting on the study.

However, the cardiovascular risks of e-cigarettes are largely unknown. That's significant, because e-cigarettes do contain some heart-related toxins present in tobacco smoke, including formaldehyde and acetone, Bhatnagar wrote. Nicotine can also affect heart function and health, he noted.

In the new study, a total of 16 e-cigarette users (defined as those who had been using e-cigarettes for at least one year) and 18 nonusers were studied. The participants were ages 21 to 45 and included both men and women. None of the participants smoked tobacco cigarettes at the time.

On the day of the study, the researchers took the participants to a quiet, temperature-controlled room, and measured the participants' heartbeats for 5 minutes while they rested and for another 5 minutes while they practiced controlled breathing. A separate blood test looked at markers of oxidative stress and inflammation, which told researchers how well the body was responding to harmful toxins.

The results indicated that the e-cigarette users showed increased levels of so-called sympathetic arousal, meaning increased adrenaline levels, in their hearts, compared with nonusers. The e-cigarette users also had higher levels of oxidative stress than nonusers did. Both increased adrenaline levels in the heart and oxidative stress are ways in which tobacco cigarettes can contribute to increased cardiovascular risk, the researchers said.

However, the researchers cautioned that the study had some limitations. First, it relied on self-reporting for behaviors such as e-cigarette use and tobacco cigarette use, which can be an unreliable method. (However, the researchers noted that they did test users' blood to confirm whether they had recently smoked tobacco cigarettes.) In addition, the researchers were unable to quantify just how many e-cigarettes the e-cig users had smoked, given the difficulty of measuring the liquid used by each per day.

Furthermore, more former smokers of tobacco cigarettes were in the e-cigarette-user group than in the nonuser group, though the researchers noted that they did not believe this explained the difference in their findings. Finally, the researchers cautioned that they cannot confirm a cause-effect relationship between e-cigarette use and cardiovascular risk based on this single, small study.

The researchers are also still unsure of how the effects of e-cigarettes on the heart compare to the effects of tobacco cigarettes on the heart, and future research is needed to determine this, Middlekauff said.

The takeaway? "If you don't already smoke tobacco cigarettes, don't start using e-cigarettes — they are not harmless," Middlekauff said.

The study and editorial are published today (Feb. 1) in the journal JAMA Cardiology.

Originally published on Live Science.

When it comes to vices, James Bond may be known for martinis, but a new study finds that he's been quite the smoker as well. And although 007 kicked the habit in 2002, he still faces the scourge of secondhand smoke, the research found.

In the study, the researchers reviewed Bond's smoking habits, as well as those of his friends, lovers and enemies, over the course of all 24 Bond films.

In the 1960s, Bond's smoking was at its peak; he lit up in 83 percent of the films in that decade, according to the study, published Jan. 16 in the journal Tobacco Control. And when he was smoking regularly in the movies, the first cigarette was lit, on average, within the first 20 minutes of the film. [The 5 Reasons We Still Love James Bond]

After the '60s, however, Bond's smoking declined — as did the American public's, CDC statistics show —and ended with the 2002 film "Die Another Day," when the spy stubbed out his last cigarette, the researchers found.

Despite the downward trends in smoking in the Bond movies, the smoking imagery "remains problematic from a public health perspective, especially given the popularity of this movie series," the researchers, led by Dr. Nick Wilson, a professor of public health at the University of Otago in New Zealand, wrote. For example, the most recent Bond movie, 2015's ""Spectre," featured several minor characters smoking cigarettes, and created an estimated 261 million "tobacco impressions" for Americans ages 10 to 29, the researchers wrote. "Tobacco impressions" refer to the number of smoking incidents in the movie, multiplied by the number of in-theater views, the researchers said.

Only one Bond movie — 2006's "Casino Royale" — contains no smokers, according to the study.

Moreover, many of Bond's sexual partners smoked, often while next to him in bed, which would have exposed Bond to high levels of secondhand smoke, the researchers said. In the 1960s, '70s and '80s, as well as in the 2010s, around 20 percent of Bond's sexual partners smoked, according to the study. And in one incident, in 1971's "Diamonds Are Forever," love interest Tiffany Case used an ashtray placed on Bond's bare chest. Of course, given the typically brief nature of Bond's relationships, the total amount of secondhand smoke he was exposed to would have remained low, the researchers added. And in the Bond movies released in the 1990s and 2000s, none of 007's partners smoked, the researchers noted.

In addition, the researchers found that, in the 1970s, the use of smoking-related spy gadgets — such as a "rocket in a cigarette" — peaked, with these devices appearing in 80 percent of the movies.

Though smoking was featured prominently in the Bond movies of the '60s and '70s, references to the dangers of smoking also appeared in the films from those decades, according to the study.

The first mention came in 1967's "You Only Live Twice," when Mr. Osato finds Bond's cigarettes and tells him, "You should give up smoking. Cigarettes are very bad for your chest." Later in the same movie, another villain, Blofeld, tells him, "It won't be the nicotine that kills you, Mr. Bond." And by 1997's "Tomorrow Never Dies," Bond describes smoking as a "filthy habit," the researchers said.

Bond's smoking seems to be "at odds with his need for physical fitness as part of his job, his high level of education and his vast knowledge on many topics," the researchers wrote. "But it does fit with a possible perception of a low life expectancy given a cumulative total of thousands of bullets being fired at him" and the increasing levels of severe violence in the films, they wrote. Plus, 15 percent of Bond's sexual partners have tried to disable, capture or kill him, they added.

This is not the first study to explore Bond's bad habits; earlier studies have looked into the spy's drinking and violent behavior, the researchers noted.

Originally published on Live Science.

How healthy are people in the U.S.? A new federal report shows that although the country has made progress in some areas, such as increasing how much exercise people get and lowering the number of teens who smoke cigarettes, it's fallen behind in others, particularly in taking care of mental health.

The new report, published today (Jan. 11) by researchers at the Centers for Disease Control and Prevention (CDC), detailed the country's progress in meeting a set of 10-year national health goals that were set in 2010 as part of an initiative called Healthy People 2020.

The initiative called for improvements in 26 different measures of public health, covering a wide range of areas including access to health care services, mental health, quality of the environment, and rates of injuries and violence.

So far, the U.S. has met or exceeded eight of the 26 objectives, and has made progress toward meeting another eight of the goals, the report said. However, in seven areas, the country has seen "little or no detectable change," and in three, the U.S. is moving in the wrong direction, the report said.

Goals met

The new report shows that the U.S. has met the national objectives for improvements in maternal, infant and child health: The national rates of infant deaths and rates of preterm live births before 37 weeks of pregnancy have both dropped down to goal levels since 2007.

The percentage of people in the U.S. who regularly meet the recommended weekly goals for physical activity increased from 18 percent in 2008 to 21 percent in 2014, surpassing the target of 20 percent, according to the report. [How to Jump-Start Your Exercise Routine in 2017]

And fewer teens now report using illegal drugs, alcohol or tobacco in the previous 30 days, the report found.

In addition, people in the U.S. exceeded both of the goals in the "environmental quality" section of the Healthy People 2020 initiative: The proportion of children ages 3 to 11 who are exposed to secondhand smoke dropped from 52 percent in 2005-2008 to 41 percent in 2009-2012, and the number of days with poor air quality dropped significantly from 2006-2008 to 2012-2014.

Finally, the rate of homicides has dropped below the 2020 goal of a reduction to 5.5 homicides per 100,000 people, the researchers found.

On the right track

The country is making progress in another eight areas, the new report said. These improvements include increases in the percentage of people who have health insurance, a rise in the percentage of adults over age 50 who were screened for colon cancer and increases in the percentage of adults with hypertension who have their blood pressure under control.

The vaccination rates for children have also increased, up from 68 percent of children who were up-to-date on their recommended vaccines in 2012 to 72 percent in 2014, according to the report. The 2020 goal is 80 percent.

The report also found that the U.S. is in on the right track in lowering the rate of death from injuries, increasing the rate of students who get a high school diploma, increasing HIV awareness among those who have the disease and decreasing the percentage of adults who smoke cigarettes.

Progress stalled

However, there hasn't been progress in every area. For example, the CDC reported no changes in the proportion of people in the U.S. who have a primary care physician or in the proportion of sexually active women who received reproductive health services in the previous year.

In addition, the rates of obesity in both adults and children have remained steady over the past decade, and there's been no change in the amount of vegetables that Americans eat daily, the report said. [Which States Are Eating Their Fruits and Veggies?]

In two other areas — the percentage of people with diabetes whose blood sugar levels are under control and the percentage of people who binge drink — the country has also failed to make progress toward the 2020 goal.

Moving backward

The report highlighted three areas in which the U.S. is moving in the opposite direction from the 2020 targets, two of which fell in the mental health category. Since 2007, the suicide rate has increased, from 11.3 suicides per 100,000 people to 12.6 suicides per 100,000 people in 2013, the report found. The number for the national suicide hotline is 1-800-273-8255.

In addition, the rate of depression in teens has increased, up from 8.3 percent in 2008 to 10.7 percent in 2013. The 2020 is goal is a reduction to 7.5 percent.

The last category in which the U.S. is moving in the wrong direction is oral health. In 2007, 44.5 percent of people ages 2 and older had been to the dentist in the previous year. By 2012, that number had fallen to 42.1 percent, the report said. The 2020 is goal is 49 percent.

Originally published on Live Science.

A 6-year-old girl in Oregon experienced severe nicotine poisoning after her parents accidentally gave her liquid nicotine meant for electronic cigarettes instead of a children's liquid pain reliever, according to a new report of the girl's case.

The child survived, but nicotine poisoning can be fatal, and the researchers warned that such cases could become more common as e-cigarettes rise in popularity.

"As electronic cigarette use proliferates, children are now increasingly at risk of toxicity from ingestions of much larger quantities of nicotine from highly concentrated refill liquid, as in our case study," Dr. Matthew Noble, an emergency medicine physician at Oregon Health and Science University, and a co-author of the report, said in a statement.

The girl had previously sprained her ankle, and was taking children's Motrin (which contains ibuprofen) for pain relief. But when the bottle was finished, the girl's mother used it to store some liquid nicotine that she had bought online to use in an e-cigarette.

The child's father didn't know the Motrin bottle contained nicotine, and he gave the child a 10-milliliter dose of the liquid for her pain, according to the report. The girl immediately felt a burning sensation in her mouth and throat, which led the father to take a small sip of the liquid. He realized it was liquid nicotine and immediately called poison control and an ambulance, the report said. [27 Oddest Medical Cases]

Before the paramedics arrived, the girl lost consciousness and began involuntarily jerking her limbs. She later regained consciousness, but did not respond to questions or commands, the report said.

The girl was taken to the emergency room, where she began vomiting and sweating, and her pulse dropped from 150 beats per minute to 60 beats per minute, the report said.

Doctors gave her an anti-nausea medication and a sedative, and placed a tube in her throat to keep her airway open. They also gave her a medical form of charcoal used to help treat drug overdoses, because it absorbs nicotine and other drugs.

About an hour after she arrived at the ER, the girl was admitted to the intensive care unit and placed on a ventilator overnight. The next day, she was taken off the breathing support and was able to respond to commands. Doctors gave her a physical exam, which showed normal results, and she was released from the hospital.

The researchers estimated that the child consumed about 700 milligrams of liquid nicotine. Some studies have estimated that ingesting as little as 500 mg of nicotine can kill an adult. An average regular cigarette delivers about 0.2 to 2.4 mg of nicotine. [10 Scientific Quit-Smoking Tips]

In addition, a blood test done about an hour after the girl arrived at the hospital showed she had a blood level of nicotine of 348 nanograms per milliliter. The level of nicotine in the blood after an adult smokes a regular cigarette is about 12 to 54 ng/ml, the report said.

The researchers also tested the liquid nicotine that the child ingested, and they estimated that the concentration of nicotine in the original product was more than double the concentration that was listed on the product label.

"This finding supports previous work demonstrating that electronic cigarette refill containers may have unreliable commercial labeling and widely variable actual nicotine concentration compared with that advertised," the researchers wrote in their report.

The report is published in the January issue of the journal Annals of Emergency Medicine.

Original article on Live Science.