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.

Ever wonder why some people build muscle more easily than others or why freckles come out in the sun? Send us your questions about how the human body works to community@livescience.com with the subject line "Health Desk Q," and you may see your question answered on the website!

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.

Ever wonder why some people build muscle more easily than others or why freckles come out in the sun? Send us your questions about how the human body works to community@livescience.com  with the subject line "Health Desk Q," and you may see your question answered on the website!

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.

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.

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

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.

• How 8 Common Medications Interact with Alcohol
• 9 Weird Ways You Can Test Positive for Drugs
• 9 Surprising, Everyday Things That May Be Bad for You

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
• 8 Tips for Parents of Teens with Depression
• 9 New Ways to Keep Your Heart Healthy

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.

Readers of a certain age will know the reference: This is your brain. This is your brain on drugs.

The simple PSA, put out by the Partnership for a Drug-Free America in 1987, accompanied these words with an image of an egg — first intact, then sizzling on a frying pan. Gripping stuff — but what do drugs do to your brain, really?

The answer to that question depends on the drug, of course, but researchers have found that one common thread is that drugs of abuse alter the brain's so-called mesolimbic pathway, known in plain English as the reward pathway. Substances act on this pathway in different ways, said Stella Vlachou, an assistant professor of psychology at Dublin City University in Ireland, but "one way or another, different drugs of abuse would definitely affect the brain's rewards system." [10 Things You Didn't Know About the Brain]

Reward circuits

This oh-so-crucial system consists of several brain structures that communicate closely with one another via nerve impulses. At one end, deep in the midbrain, is the ventral tegmental area. At the other are the nucleus accumbens and the olfactory tubercle, both found in a region called the ventral striatum in the forebrain. The main neurotransmitter responsible for firing off signals in this pathway is dopamine, which plays an excitatory role, stimulating neurons to fire. Dopamine is a major culprit in addiction, Vlachou told Live Science, though it plays a role in normal, healthy behaviors, too.

"It is released at higher levels when we are motivated to work on something that we like, when we have a strong desire about something, when we experience something we would call reward or pleasure," she said.

Whether directly or indirectly, habit-forming substances act upon this reward system. Psychostimulants such as cocaine and amphetamines affect levels of dopamine directly, Vlachou said. In contrast, other drugs — such as opioids, nicotine and even THC (tetrahydrocannabinol), the psychoactive ingredient in marijuana — act on neurotransmitters or their receptors that indirectly affect the amount of dopamine the brain releases or detects. Some drugs, Vlachou said, have even more complex actions, perhaps interacting with the molecules that shuffle neurotransmitters across the synapses, or gaps between neurons.  

Drug by drug

There are a lot of drugs out there, especially since the advent of synthetic compounds that can mimic naturally derived substances or combine the effects of the old standards. The National Institute on Drug Abuse (NIDA) curates a long list of drugs and their effects, but here are some highlights:

Marijuana: The psychoactive ingredient in cannabis is called delta-9-tetrahydrocannabinol, better known as THC. As the name suggests, THC is a cannabinoid, and it just so happens that the body has its own cannabinoid system, known as the endocannabinoid system. Endocannabinoid receptors are found in both the brain and the immune system. In the brain, they're linked to a huge range of functions, including memory, appetite, pain sensation and sleep. They're even partially responsible for the "runner's high" that comes from intense exercise — at least in mice. As one 2013 paper in the journal Cerebrum put it, "Given the enormous complexity of the brain, the endocannabinoid system could affect behavior in an almost limitless number of ways: Simple generalizations of what will happen when CB1 receptors are globally turned on or off are not feasible." (CB1 receptors are the most prominent cannabinoid receptors in the brain.)

Thanks to the widespread nature of the endocannabinoid system, it's no surprise that THC's effects on the brain are also widespread. By interacting with cannabinoid receptors in the hippocampus and the orbitofrontal cortex — two areas of the brain associated with attention and memory — THC can create short-term memory loss and impair thinking. There are also cannabinoid receptors in the cerebellum — the structure in the back of the brain that regulates movement — which explains why someone who's high on pot may not move quickly. And yes, the cascade of THC's effects also stimulates dopamine release, making the whole experience (usually) quite pleasant. [7 Ways Marijuana May Affect the Brain]

Nicotine: Present in tobacco products and e-cigarettes, nicotine is the stuff that makes smoking so addictive. By coincidence, nicotine is very similar in structure to a neurotransmitter called acetylcholine, Vlachou said. Once in the brain, nicotine binds to acetylcholine receptors. This abundance of compounds binding to the receptors prompts the brain to release less acetylcholine, meaning the person needs nicotine to feel normal, according to the NIDA.

But nicotine affects other neurotransmitters, too. Some of the acetylcholine receptors it binds to are on cells that are responsible for releasing dopamine, so nicotine indirectly increases dopamine, tickling those mesolimbic reward pathways. It may also affect dopamine through its interactions with acetylcholine receptors that control an inhibitory neurotransmitter called gamma-aminobutyric acid and an excitatory neurotransmitter called glutamate, which, in turn, can also influence how much dopamine is released.

Opioids: Opioids include naturally derived substances, like heroin, as well as synthetic ones, like fentanyl. They're powerful short-term painkillers because they act on opioid receptors in the brain and spinal cord, which — sensing a theme? — themselves evolved to respond to compounds produced naturally inside the body, including endorphins.

When stimulated by an opioid, whether homemade or not, these receptors inhibit the nerves from sending pain signals. But opioid receptors are also found across the brain, including in the rewards pathway, where they may be involved in pleasurable sensations associated with food and sex, according to a 2009 review. Repeatedly dosing oneself with substances like heroin or prescription opioids, though, prompts the brain to stop producing as many of its own opioids. This can lead to tolerance (the need to take more opioids to get high) and dependence (horrible withdrawal symptoms that drive people to take the drug simply to feel well), according to a 2002 review in the journal Addiction Science and Clinical Practice.

What makes opioids truly deadly, though, are their actions in the brain stem, which controls breathing and other basic, automatic functions. When a person takes a high level of opioids, the molecules inhibit the neurons in the brain stem that control breathing. The result is overdose, often fatal.

Cocaine: Cocaine affects dopamine levels in the brain directly, creating an extremely pleasurable rush as the neurotransmitter floods the mesolimbic reward system. Cocaine molecules bind to a protein in the brain called a dopamine transporter, which acts like a synaptic garbageman, clearing dopamine from the gaps between neurons so that it doesn't continually stimulate the nerve cells to fire. With cocaine as a hitchhiker, the dopamine transporter can't do its job. So dopamine builds up in the synapse, and nerve cells keep firing. It's euphoric in the short term but may rob the brain of gray matter in the long term, according to 2012 research.

Psilocybin: The active ingredient in "magic mushrooms" can create quite a trippy experience, with effects ranging from the sense that time is slowing down to the feeling of being one with the universe. Research suggests that psilocybin works mostly by mimicking the neurotransmitter serotonin. Serotonin plays an important role in how the brain processes emotions, and the frontal cortex — the seat of personality and complex thought — is abundant with serotonin receptors. [Trippy Tales: The History of 8 Hallucinogens]

That means psilocybin has strong effects on complex processes — it might even alter personality permanently. The hallucinatory effect that causes people to see auras or colorful trails behind moving objects seems to be linked to the way psilocybin alters the functional connections, or communication pathways, between brain regions, according to 2014 research. The drug seems to promote the appearance of strong, long-range connections that could explain why people using it feel more connected and creative.

Originally published on Live Science.

With names like "Banana Pudding," "Blueberry Cinnamon-Streusel Muffin" and "Butter Crunch," the flavoring ingredients in electronic cigarettes sound not only harmless but immensely appealing. But some of the liquids used in e-cigarettes may in fact have highly toxic effects on human cells tested in a lab, a new study reveals.  

Researchers in North Carolina found that some of the ingredients used in so-called "e-liquids" are more toxic than nicotine alone and many of them are more toxic to human cells than the main ingredients in these liquids, which are propylene glycol and vegetable glycerin, according to the findings, published today (March 27) in the journal PLOS Biology. 

E-cigarettes work by heating a liquid solution composed of propylene glycol, vegetable glycerin, flavorings and typically nicotine, until the liquid vaporizes. [E-Cigarettes: What Vaping Does to Your Body]

But little is known about the potential toxicity and chemical composition of most substances found in e-liquids, the researchers said.

In the new study, the researchers tested 148 e-liquids. They found that the e-liquids contained a total of 143 chemicals, which indicates that the ingredients in e-cigarettes are extremely diverse, said senior study author Robert Tarran, an associate professor of cell biology and physiology at the University of North Carolina School of Medicine.

With more than 7,700 commercially available e-liquid flavors — and the U.S. Food and Drug Administration just beginning to regulate the ingredients in e-cigarettes — a quicker method is needed to screen e-liquids to evaluate their safety and chemical makeup, according to the study.

So, the researchers did just that: In the new study, they developed a way to measure the toxicity of a large number of e-liquids at once. In addition, the scientists looked at how quickly e-liquids can affect the growth of human tissue culture cells — which aren't lung cells, but are good for testing purposes — and whether these e-liquids can kill cells, Tarran told Live Science.

After the researchers had identified some patterns of toxicity, they then used cells taken from people's lungs to confirm these observations, Tarran said.

Toxicity of e-liquids

The study revealed that the more chemicals an e-liquid contained, the more toxic it tended to be. The findings also showed that e-liquids containing either vanillin or cinnamaldehyde, two common flavor compounds widely used in e-cigarettes, were linked with higher toxicity values.  

Although the new study looked at human cells in the lab and didn't actually study the health effects of vaping in people, Tarran said he feels that the cells they used have been shown to be highly predictive of lung diseases, such as cystic fibrosis and chronic obstructive pulmonary disease (COPD). This makes him feel confident of their actual predictive value in people, but much more work needs to be done to learn more about the toxicity of e-liquids and the health effects of vaping, he added.

In three previous studies of human cells, Tarran said that he and his research team have found that vaping can lead to changes in the lungs, although the long-term consequences of using e-cigarettes are not yet known. These earlier studies have shown that vaping can suppress the immune system, change secretions in the airways and cause changes to proteins that help detoxify the lungs, suggesting that vaping is, in fact, a toxic burden to the lungs, he said.

Similar screenings of e-liquids could be performed in animals rather than in test tubes, Tarran said. However, animal research would be more time-consuming and expensive, and is not feasible for the more than 7,000 e-liquids being sold, he noted.

There is still a great deal that is not known about the ingredients in e-liquids. But this study suggests that the e-liquids that are highly toxic can be identified and prioritized for further research, Tarran said.

The public should push for additional research on the safety of e-cigarettes and better standards for the ingredients in these products, Tarran said. Most e-liquids do not reveal their chemical contents on the e-cigarette packaging, other than their nicotine concentration and  their ratio of propylene glycol to vegetable glycerin, he said.

To find out more about e-liquids, the researchers have created a searchable database at eliquidinfo.org.

Originally published 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.

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.

Teens who regularly or occasionally use pot are more likely to take other illegal drugs or use other harmful substances by age 21, a new study suggests, adding weight to the idea that marijuana does indeed act as a "gateway" to the use of other drugs.

Researchers found that teenagers in the study who regularly used marijuana were 26 times more likely to have used other illegal drugs, such as cocaine, amphetamines or hallucinogens, by the time they reached early adulthood, compared with teens who hadn't smoked pot, according to the findings published online today (June 7) in the Journal of Epidemiology and Community Health.

The study also revealed that the teens who typically used marijuana once a week or more were 37 times more likely to be hooked on nicotine, and three times more likely to have harmful drinking habits by age 21 than their peers who did not use marijuana. [25 Odd Facts About Marijuana]

The findings show that the more an individual uses marijuana during adolescence, the more likely he or she will develop problematic substance use behaviors in early adulthood, said lead study author Michelle Taylor, a senior research associate in epidemiology at the University of Bristol in England.

Previous studies have found mixed results when they looked at whether using marijuana during adolescence acts as a gateway to the use of other illegal drugs in early adulthood. And the evidence of a link between teen marijuana use and later tobacco use or alcohol problems has also been inconsistent.  

In the new study, researchers analyzed data from the Avon Longitudinal Study of Parents and Children, a long-running study in the U.K. that has followed women and their children. The study began when the women were first pregnant, all in 1991 or 1992.

For the new report, the researchers looked at questionnaires that more than 5,300 of the children completed. The kids were surveyed at least three times between ages 13 and 18, and asked about the frequency of their use of drugs, alcohol and tobacco in the previous three months. They were also sent a follow-up survey by mail to measure these behaviors at age 21.

The researchers also took into consideration the smoking, drug and alcohol habits of the teens' mothers, both when they were pregnant and when the child was growing up, because a mother's habits can influence her child's chances of developing similar behaviors as a teen or young adult, the researchers said.

Teen marijuana use

The surveys from the teen years showed that about 80 percent of the participants reported that they had not used marijuana. But 14 percent of the teens started using marijuana by age 15, using it occasionally, meaning less than once a week. And 2 percent of them started using marijuana by age 13, also using it occasionally, or less than once a week. [7 Ways Marijuana May Affect the Brain]

Slightly more than 3 percent of the teens said they were regular marijuana users, meaning they used it one or more times a week, according to the findings.

The researchers found that the teens who had said they either occasionally or regularly used marijuana were more likely to become tobacco-dependent, have harmful levels of alcohol consumption, and use other illicit drugs in early adulthood, Taylor said.  

These results add further evidence to the idea that adolescent marijuana use does predict later problematic substance use in early adulthood, Taylor told Live Science.

She noted that although the findings establish a correlation between teen pot use and the use of other illegal drugs by age 21, the study does not show a cause-and-effect relationship between the two. 

The study was also unable to identify the reasons why teens' early use of marijuana was linked to a greater likelihood of using other illegal drugs by age 21. The study authors speculate that genetic vulnerabilities as well as biological, behavioral and environmental factors can all play a role in substance use.

Future research needs to focus on teasing out these reasons to help identify individuals who might be at risk for these behaviors and to develop effective policies to advise teens and young adults of the harms of these substances, Taylor 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.

Smoking marijuana during pregnancy doesn't appear to increase the risk of preterm birth or other harmful birth outcomes, a new review study suggests.

The researchers did initially find a link between smoking marijuana during pregnancy and an increased risk of having a preterm or low-birth-weight baby. But when they took into account whether the pregnant women also smoked tobacco in addition to marijuana, this increase in risk went away.

In other words, the risk of having either a preterm birth or a baby with a low birth weight was due to tobacco smoking, and marijuana use by itself was not linked to these outcomes, the researchers said.

The findings "do not imply that marijuana use during pregnancy should be encouraged or condoned," the researchers, from Washington University School of Medicine in St. Louis, wrote in the October issue of the journal Obstetrics & Gynecology. Rather, the lack of a link between marijuana use and harmful pregnancy outcomes suggests that attention should be focused on helping pregnant women to stop using tobacco or other substances known to have adverse effects on the pregnancy, they said. [7 Ways Marijuana May Affect the Brain]

Previous studies on marijuana use during pregnancy have had conflicting results, with some showing that the drug increases the risk of harmful birth outcomes and others showing no increase in risk. But many of these studies were limited because they did not consistently take into account tobacco smoking, or relied entirely on women's self-reports of marijuana use (which can be unreliable).

In the new study, the researchers analyzed information from 31 previous studies that together included more than 7,800 women who used marijuana during pregnancy and more than 124,000 women who did not use marijuana during pregnancy. The researchers only included studies that were designed in a way that allowed them to analyze marijuana use separately from tobacco use. They also included some studies that used objective measures of marijuana use during pregnancy — such as a positive urine test — in addition to studies that used self-reports of marijuana use.

They found that overall, women who smoked marijuana during pregnancy were 43 percent more likely to have a low-birth-weight baby, and 32 percent more likely to have a preterm birth, than women who didn't smoke marijuana during pregnancy.

But when they looked at women who smoked only marijuana during pregnancy and did not use tobacco, they found that these women were not at increased risk for either preterm birth or low-birth-weight babies. In contrast, women who smoked marijuana and tobacco were 85 percent more likely to have a preterm birth, compared with women who didn't use either substance.

Women who smoked marijuana during pregnancy were also not at increased risk for miscarriage or having a baby that was smaller than normal for their gestational age.

It's important to note that the study did not look at the long-term health of babies whose mothers smoked marijuana during pregnancy, so more research is needed to look at this question. A 2014 study of animals and human cells suggested that marijuana use during pregnancy may affect the formation of connections between brain cells, possibility affecting brain development.

Original article on Live Science.

Nearly 21 million Americans ages 12 and older had a substance use problem in 2015, according to a new federal estimate.

Among those with a substance use disorder, three out of four people (or about 15.7 million) had a substance use disorder related to alcohol, Kana Enomoto, the principal deputy administrator of the Substance Abuse and Mental Health Services Administration (SAMHSA), said at a news conference today (Sept. 8).

In addition, 1 in 3 people with a substance use disorder had a disorder related to drug use, and 1 in 8 people had a disorder involving both drugs and alcohol, Enomoto said.

For the report, the federal government used the definitions of substance use disorders as they are explained in the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders. People are considered to have a substance use disorder if, for example, they have strong urges to use a substance or can't control their use of it, or if their use impairs them in social situations or leads to risky behavior.

The report also said that an estimated 27.1 million people in the U.S. used an illegal drug in the past month. The national estimates are based on the findings of the National Survey on Drug Use and Health, an annual survey on drug use. The 2015 survey included interviews with about 67,500 people.

The survey also revealed that, in 2015, about 1 in 12 Americans needed some form of substance use treatment, Enomoto said. But only about 11 percent of these people actually received treatment, she said. [The Drug Talk: 7 New Tips for Today's Parents]

Drug use in the U.S.

Marijuana remains the most commonly used drug, Enomoto said. Among people who reported having used any drugs in the previous month, 87 percent said that they had used marijuana, she said.

And more people reported using marijuana during 2015 than during any single year between 2002 and 2013, according to SAMHSA. But notably, marijuana use didn't increase among adolescents, Enomoto said. Rather, the overall increase was driven largely by more use of the drug among adults ages 26 and older, according to the report. In 2002, 4 percent of adults ages 26 and older who were surveyed reported using marijuana, but in 2015, that number was 6.5 percent.

Among those who reported using opioids in the past year, prescription drugs were the most common type used, Enomoto said. An estimated 3.8 million people in the U.S. currently misuse prescription pain relievers, according to the report.

An estimated 830,000 people in the U.S. used heroin in 2015, Enomoto said — more than double the number from 2002. She noted that there was a slight decrease, however, in heroin use from 2014 to 2015, but it was not statistically significant (meaning it could have been due to chance).

In addition, nearly 300,000 people knowingly used the drug fentanyl in the past year, Enomoto said. Fentanyl is a prescription painkiller that is up to 100 times more potent than morphine and is often linked to fatal overdoses. In many cases, people who use heroin may unknowingly use fentanyl, because heroin may be laced with fentanyl.

Prevention efforts are working

However, the findings also suggest that the prevention efforts do work to curb substance use, Enomoto said.

For example, although alcohol remains a problem among adolescents, the rate of teens who reported using alcohol in the past month has decreased significantly in the past 13 years, Enomoto said. In 2015, 9.6 percent of teens reported drinking in the past month — down from 17.6 percent of teens in 2002, according to the report.

There also has been a reduction in cigarette smoking among teens, Enomoto said. In 2002, nearly 1 in 8 teens reported having smoked in the past month, but in 2015, just 1 in 20 teens reported having smoked in the past month, according to the report.

Originally published on Live Science.

San Francisco has a new claim to fame: The city has the highest rate of marijuana use in the country, according to a new survey.

In the survey, which was conducted from 2012 to 2014 nationwide, 15.5 percent of people in San Francisco said they had used marijuana in the past month. That's much higher than the national average of 7.7 percent.

Perhaps not surprisingly, parts of Colorado (where recreational marijuana use is legal) also had high rates of marijuana use. About 14.8 percent of people in the northeastern part of the state, the Denver area, and the northwestern and southwestern parts of the state reported using marijuana in the past month.

Also, in the northern part of Alaska, nearly 15 percent of people reported past-month marijuana use, and rates were above 14 percent in parts of Rhode Island and Washington state, according to the survey, which was conducted by the Substance Abuse and Mental Health Services Administration (SAMHSA). (Alaska and Washington also have legalized recreational marijuana use.) [11 Odd Facts About Marijuana]

A region in the southernmost part of Texas had the lowest rate of marijuana use, with 3.9 percent of people reporting using marijuana in the past month. Rates were also low in parts of south-central Kansas, northern North Dakota and northern Utah, where less than 4.5 percent of people reported past-month marijuana use in all three areas.

The survey shows that rates of marijuana use vary widely across the nation, and even within states, the researchers said.

"This information can help public health officials and others better gauge the marijuana-related prevention and treatment needs in their communities and fine-tune their programs and services to best address them," Fran Harding, director of SAMHSA's Center for Substance Abuse Prevention, said in a statement.

The report also looked at perceptions of the risk of harm from using marijuana, and found that the percentage of people who think the drug may be harmful tends to be lower in places that had higher rates of marijuana use.

An area of the District of Columbia (called Ward 3) had the lowest perception of risk in the country, with just 14 percent of people saying they perceived there was a "great risk of harm" from smoking marijuana once a month. In contrast, nearly 50 percent of people in Florida's Miami-Dade County and Monroe County (which includes the Florida Keys) said they perceived a great risk of harm from smoking marijuana once a month.

In the nation as a whole, 28 percent of people said they perceived a great risk of harm from smoking marijuana once a month.

The survey involved more than 200,000 people ages 12 or older in the United States.

Original article on Live Science.

Middle-age people who have smoked marijuana for many years may have a higher risk of developing gum disease, according to a new study.

However, the study did not find a link between long-term marijuana use and several other health problems associated with cigarette smoking, the researchers said.

"What we're seeing is that cannabis may be harmful in some respects, but possibly not in every way," Avshalom Caspi, a co-author of the study and a professor of psychology and neuroscience at Duke University, said in a statement. "We need to recognize that heavy recreational cannabis use does have some adverse consequences, but overall damage to physical health is not apparent in this study." [11 Odd Facts About Marijuana]

In the study, the researchers looked at 1,037 people who were born in New Zealand in 1972 or 1973, and followed them until the people were 38 years old. The researchers examined whether the people had used marijuana when they were between 18 and 38, and whether they had physical health problems at age 38.

The researchers found that, among the 38-year-olds who had regularly smoked pot for 15 to 20 years, 55.6 percent had gum disease, also called periodontal disease. In comparison, only 13.5 percent of the 38-year-olds who had never used marijuana had gum disease. In some cases, this disease may lead to tooth loss.

The results also showed that the people who had smoked marijuana for up to 20 years had brushed their teeth and flossed less frequently than those who had never smoked marijuana, according to the findings, published today (June 1) in the journal JAMA Psychiatry. However, the less-frequent brushing and flossing did not explain the link between marijuana use and gum disease, which suggests that marijuana use itself may lead to damage to the gums. [5 Surprising Ways to Banish Bad Breath]

Researchers have long known that cigarette smoking has been associated with a higher risk of gum disease, said Dr. Ronald P. Burakoff, chairman of dental medicine at Northwell Health in New Hyde Park, New York, who was not involved in the study. "So I am not surprised that marijuana use also is associated with periodontal disease," Burakoff told Live Science.

In the new study, the researchers also looked at the dental and general physical health of 484 people in the study who had smoked cigarettes on a daily basis at some point in their lives. In line with previous research, they found that those people were also more likely to have gum disease than those who had never smoked.

But these people were also more likely to have problems with their lung function, higher blood sugar levels and inflammation than those who had never smoked cigarettes.

In contrast, when the researchers looked at the same aspects of lung function and cardiovascular health among the people who had smoked marijuana for up to 20 years, they did not find these aspects were worse than they were in the people who had never smoked marijuana.

One limitation of the new study was that the researchers looked only at specific aspects of the people's health assessed at a specific age, the researchers said. This means that the use of marijuana still may be linked to other health problems, such as cancer, that tend to occur later in life, they said.

Previous research has found links between the use of marijuana and weight gain, brain changes and the worsening of sexual function, among other health problems.

The new results "should be interpreted in the context of prior research showing that cannabis use is associated with accidents and injuries, bronchitis, acute cardiovascular events and, possibly, infectious diseases and cancer, as well as poor psychosocial and mental-health outcomes," the researchers wrote.

Originally published on Live Science.

Just 6 percent of adults in the U.S. have adopted all five key health habits that are linked with better health or longer life, according to a new report.

But adults in some states are far healthier than others: The states with the highest percentages of people who engage in all five habits are Utah (with 11.3 percent), Hawaii (9.2 percent) and Oregon (9 percent), according to the report published today (May 26) in the journal Preventing Chronic Disease.

The five health habits the researchers looked at were: maintaining a healthy body weight (with a BMI between 18.5 and 24.9), getting at least 7 hours of sleep, exercising (150 minutes of moderate exercise, or 75 minutes of intense exercise weekly), drinking alcohol in moderation or not at all, and not smoking. For the report, the researchers at the Centers for Disease Control and Prevention looked at the data from nearly 400,000 U.S. adults ages 21 and older who participated in a national survey.

"This is the first time in 30 years that a comprehensive look at these five healthy behaviors has been undertaken," said Dr. Wayne Giles, a chronic disease prevention researcher at the CDC and a co-author of the report.  "What we found is that the vast majority of adults engage in three to four of these behaviors, however, only 6 percent engage in all [five]," Giles told Live Science in an email. [Jump to infographic: 5 Key Health Habits in US Adults: Full List of States]

Nationally, 24 percent of adults engage in four of the habits, and 35.2 percent are engaging in three, according to the report.

The states with the lowest percentages of people doing all five behaviors are Arkansas, North Dakota (both with 4.2 percent), Tennessee and Mississippi (both with 4.3 percent), according to the report.

"The geographic data are a particularly intriguing finding from this study, and illustrate that where you live can have a huge impact on whether or not people engage in these behaviors," Giles said.

The report is rooted in an influential 1982 study of the residents of Alameda County, California, the researchers said. That study revealed that these five behaviors were key to preventing chronic disease and reducing early mortality, according to the new report.

Since then, most studies that have attempted to find the percentage of Americans who do all five of these behaviors have lacked data on the percentage of people who get at least 7 hours of sleep, the researchers wrote in their report. Before 2015, there was no formal government recommendation for how much sleep adults should get, they noted.

But it's important to look at these behaviors all together, and see how many people are doing most or all of five them, the researchers wrote. [9 Healthy Habits You Can Do in 1 Minute (Or Less)]

"These behaviors tend to reinforce each other," Giles said. "For example, some people tend to smoke when they drink, and we know that physical activity can be important in helping people obtain adequate sleep, and inadequate sleep, physical inactivity and excessive alcohol are all related to obesity," he said.  

Only 1.4 percent of respondents reported that they engaged in none of the five behaviors, the report found. The number was highest in Pennsylvania (2.5 percent), and Arkansas, Idaho and Ohio (all with 2.3 percent). The number was lowest in Utah (0.7 percent), and Vermont and Arizona (both with 0.8 percent).

The five behaviors are probably not equal in their health consequences, the researchers wrote in their report. "In terms of health consequences, tobacco is the leading cause of preventable deaths," Giles said. Tobacco use causes more than 400,000 deaths in the U.S. each year, he said. Obesity is related to slightly more than 100,000 deaths, he added.

For the report, the researchers considered moderate drinking to mean no more than two drinks per day for men, and no more than one per drink for women, with no binge drinking (five or more drinks on one occasion for men, or four or more for women), and no heavy drinking (15 or more drinks during one week for men, or eight or more in one week for women). [7 Ways Alcohol Affects Your Health]

"This study demonstrates a higher percentage of five health-related behaviors in the Pacific and Rocky Mountain states than in Southern states," the researchers wrote. The researchers noted that the Southern states, along with the states that border the Ohio River (including West Virginia, Kentucky and Ohio), have higher rates of chronic obstructive pulmonary disease and diabetes.

The researchers noted that their study was limited because it relied on self-reporting, and that the rates of people who responded to the survey from some states were lower than others.

Originally published on Live Science.

Following a healthy lifestyle — which includes maintaining a healthy weight, exercising regularly and refraining from smoking — may prevent cancer, a new study finds.

Healthy lifestyle choices could potentially prevent 20 to 40 percent of cancer cases and about half of cancer deaths, the study found.

The study, published today (May 19) in the journal JAMA Oncology, comes after a different study, published last year, found that the majority of cancers were caused by random mutations in DNA, and suggested that therefore these cases were unpreventable. [10 Do's and Don'ts to Reduce Your Risk of Cancer]

The new findings, however, "provide strong support for the argument that a large proportion of cancers are to due environmental factors and can be prevented by lifestyle modification," the authors of the new study, Dr. Mingyang Song, a research fellow in epidemiology at Massachusetts General Hospital, and Dr. Edward Giovannucci, an associate professor of medicine at Harvard Medical School, wrote in their paper.

In the study, Song and Giovannucci looked at more than two decades of data on nearly 136,000 white men and women who were enrolled in either the Nurses' Health Study or the Health Professionals Follow-up Study. All of the participants had regularly responded to surveys about their lifestyles, and the researchers divided the participants into two groups: a low-risk group, all of whom followed a healthy lifestyle, and a high-risk group, all of whom did not.

The researchers defined a healthy lifestyle as never or no longer smoking and never drinking alcohol or drinking moderately (one drink a day or less for women and two drinks a day or less for men). The researchers also specified having a BMI between 18.5 and 27.5, and exercising regularly (either at least 150 minutes of moderate exercise per week or at least 75 minutes of vigorous exercise per week).

The researchers found that women in the high-risk group were 25 percent more likely to get cancer and 48 percent more likely to die from cancer during the study period than the women in the low-risk group.

Men in the high-risk group were 33 percent more likely to get cancer and 44 percent more likely to die of cancer than the men in the low-risk group, according to the study. [The 10 Deadliest Cancers and Why There's No Cure]

The researchers noted that all of the people in the study were health professionals and therefore potentially more health-conscious than the general population. If the results of the study were applied to the general population of white adults, a healthy lifestyle could prevent between 40 and 70 percent of cancers, the researchers estimated.

The researchers noted that their study only included white men and women, the results may not apply to other ethnicities. However, all of the healthy lifestyle factors included in the study have been shown to decrease cancer risk in diverse ethnic groups, they added. 

In an editorial accompanying the new study in the journal, two researchers who were not involved in the new study or the one published last year wrote that the new findings show that "cancer is preventable."

"As a society, we need to avoid procrastination induced by thoughts that chance drives all cancer risk or that new medical discoveries are needed to make major gains against cancer," wrote Dr. Graham A. Colditz and Siobhan Sutcliffe, both public health researchers at the Washington University School of Medicine in St. Louis. "Instead we must embrace the opportunity to reduce our collective cancer toll by implementing effective prevention strategies and changing the way we live," they wrote.

Follow Sara G. Miller on Twitter @saragmiller. Follow Live Science @livescience, Facebook & Google+. Originally published on Live Science.

Electronic cigarettes, or e-cigs, have been on the market in the U.S. since 2008 and have gained wider use in recent years. Now, evidence is beginning to emerge on e-cigs' short-term effects, and their positive and negative impact on people's health.  

E-cigarettes are battery-powered devices that heat a liquid — usually containing nicotine mixed with the chemicals propylene glycol and glycerin, and often flavorings ranging from bubble gum to watermelon — into a vapor that users can inhale. They deliver nicotine, a highly addictive drug, to the body without producing any smoke.

This month, the U.S. Food and Drug Administration announced that its authority to regulate tobacco products will now extend to include e-cigarettes. The devices — along with cigars, hookah and pipe tobacco — will now be regulated in a similar way to conventional cigarettes. The new rules, which take effect on Aug. 8, also banned the sale of these products to people under age 18 both in stores and online. [4 Myths About E-Cigarettes]  

But because e-cigs are relatively new nicotine-delivery products, there are many unanswered questions about their safety and health impacts, including questions about their long-term use and effectiveness in helping traditional smokers to quit. What, exactly, is in an e-cigarette, and how do these chemicals affect the heart and lungs as well as a person's overall health? Live Science asked two tobacco experts for their insight into these questions, and here is what they said.

What's known about e-cigs

"There is no question that a puff on an e-cigarette is less dangerous than a puff on a conventional cigarette," said Stanton Glantz, a professor of medicine and the director of the Center for Tobacco Control Research and Education at the University of California, San Francisco.

Because e-cigarettes create a vapor rather than produce a tobacco smoke, they generally deliver less nicotine to users than cigarettes do, Glantz said. [Infographic: How E-Ciggs Work]

However, this doesn't mean the devices always represent a safer step down from cigarettes. In fact, one of the most dangerous things about e-cigarettes is that they may keep people smoking conventional cigarettes longer, rather than encourage them to attempt to quit, he said. Although estimates vary, anywhere from 70 to 90 percent of e-cigarette users are "dual users," meaning they continue to smoke regular cigarettes after they begin vaping, Glantz said.

But regardless of how the nicotine is delivered — whether through e-cigs or conventional cigarettes — it still has effects on the body. The drug is a cardiovascular stimulant, and can potentially worsen heart disease in people who already have severe heart conditions. However, it's not known whether nicotine alone can cause heart disease in people who don't have heart problems, said Dr. Michael Siegel, a tobacco researcher and professor of community health sciences at the Boston University School of Public Health.

But there's some evidence that e-cigarettes can have a substantial effect on blood vessels, and may increase people's heart attack risk in that way, Glantz said.

What's more, nicotine is poisonous in its concentrated, e-liquid form, and there have been an increasing number of cases of infants and young children accidentally ingesting it, Siegel said.

Nicotine also has effects on reproductive health, and exposure to nicotine during pregnancy, regardless of its delivery method, can harm the developing fetus and lead to babies born with low birth weights, he said.

The use of e-cigarettes by kids of high school age has soared – CDC statistics show that 1.5 percent of high school teens had tried e-cigs in 2011, compared with 16 percent in 2015. The rise has occurred even as researchers are finding more evidence that nicotine can be toxic to a young person's still-developing brain and body systems, Glantz said. Studies have also shown that kids who use e-cigarettes have more respiratory problems and take more days off from school, he said.

In addition to the nicotine, e-cigs' other chemicals may also affect health. Research on the vapors emitted and inhaled from e-cigarettes has shown they deliver particles small enough to reach deep into the lungs and that they are not the "harmless water vapor" that marketers may claim, Glantz told Live Science.

Propylene glycol, a chemical found in e-liquids, can irritate the eyes and airways, Siegel said. Early studies have also revealed that when propylene glycol or glycerin are heated and vaporized, they can degrade into formaldehyde and acetaldehyde, he said. Both of these chemicals are considered carcinogens, although it's not yet clear how repeated exposure to them may cause cancer, he said. [10 Scientific Quit-Smoking Tips]

One of the biggest safety risks of e-cigarettes is the potential for their lithium-ion batteries to explode, sometimes into a person's face or eyes, Siegel said. There is clearly a need for standards to make these batteries safer, he said.

But all in all, even if e-cigarettes involve some health risks, they are not more toxic than smoking cigarettes, and so anything that can get people away from tobacco is moving them in the right direction, Siegel said. He believes that vaping gives people a safer alternative because although users are still getting nicotine, they are getting lower levels of some of the toxic substances and carcinogens found in cigarette smoke, he said.

Eventually, the goal is to get people off vaping and to quit completely, but people have to start somewhere, Siegel said. He also acknowledged that many of his colleagues in public health don't share his opinion. Rather, they view e-cigarettes as a gateway to smoking conventional cigarettes, especially for young people, or as a method of getting nicotine that actually diminishes people's interest in quitting.  

Glantz falls into this latter category. In an analysis he and a colleague published earlier this year, they found that adult smokers who use e-cigarettes are about 30 percent less likely to stop smoking than people who attempt to quit smoking without turning to vaping, he said. One possible explanation is that people may generally use e-cigarettes as part of a "taper-down" strategy, which is less effective than quitting cold turkey, he suggested.

The unknowns about e-cigs

Studies evaluating whether e-cigarettes are less harmful than cigarettes have been inconclusive, according to a review of studies published in the journal Tobacco Control in May 2014.

Moreover, the long-term health effects in people who get nicotine in a vaporized form over time are not known, Siegel said. It's also unclear whether propylene glycol, a known irritant to the respiratory tract, could result in lung problems after decades of vaping, he said.

And because e-cigarettes have been on the market for only about 10 years, there have been no long-term studies of people who have used them for 30 to 40 years. Therefore, the full extent of e-cigs' effects on heart and lung health, as well as their cancer-causing potential, over time is not known, Glantz told Live Science.

Another unanswered question is how the flavorings used in the devices may affect people's health. Nearly 500 brands and 7,700 flavors of e-cigarettes are currently on sale, according to the American Lung Association. This wide variety of flavors has helped make vaping appealing to young people. 

It's not yet known whether these flavorings have any respiratory effects when they are vaporized and inhaled, Siegel said. More research is needed to identify any hazards associated with the potential inhalation of flavoring agents, he said.  

In addition, little is known about how the flavoring agents in e-cigarettes may influence nicotine's addictive qualities, Glantz said.

More work needs to be done to understand the dynamics between smoking traditional cigarettes and also using e-cigarettes in people who are dual users, he said. Future research also needs to look at whether using both traditional cigarettes and e-cigs interferes with the desire to quit, and whether using e-cigarettes is an effective strategy for quitting smoking compared with other methods, such as the nicotine patch and behavioral counseling, Glantz said.

The FDA has not approved e-cigarettes as a smoking cessation aid, he added.

Follow Live Science @livescience, Facebook & Google+. Originally published on Live Science.

Moms-to-be have yet another reason to snub out their cigarettes: A new study links smoking while pregnant to changes in the fetus's DNA.

These changes may partly explain the link between smoking during pregnancy and health complications in children born to smokers, the study said. These complications can include low birth weight, along with increased risk of asthma and cleft lips or palates.

Despite years of health warnings, approximately 12 percent of pregnant women in the United States still smoke, the researchers wrote in the study, published today (March 31) in the American Journal of Human Genetics. [Kick the Habit: 10 Scientific Quit-Smoking Tips]

To examine the effects of smoking on fetal DNA, the researchers looked at nearly 7,000 newborns and their mothers from around the world. Information about the mothers' smoking habits was gathered through questionnaires, the study said. The researchers also collected a sample of blood from each newborn's umbilical cord.   

The researchers were looking for epigenetic changes to the newborns' DNA. Epigenetic changes are alterations that don't change the sequence of DNA, but rather affect whether certain genes are turned "on" or "off." One specific type of epigenetic change the researchers looked for is called "methylation," in which a small molecule is added to a part of the DNA, preventing that section from being turned on.

The researchers found that in newborns whose mothers described themselves as "sustained smokers," there were more than 6,000 places where the DNA differed from the DNA of newborns who were born to nonsmokers, the study said.

The researchers also looked for epigenetic changes in older children, with an average age of 7, whose mothers had smoked while pregnant. Results showed that many of the changes were still present, according to the study.

In addition, the researchers found that the epigenetic changes observed in newborns were to similar to those previously observed in adult smokers, Dr. Stephanie London, an epidemiologist at the National Institute of Environmental Health Sciences and a co-senior author on the study, said in a statement.

This finding shows that although a fetus isn't breathing in the smoke though its lungs, "many of the same things are going to be passing through the placenta," London said.

Of note, some of the epigenetic changes that the researchers observed have previously been linked to cleft lips and palates and asthma, the researchers wrote.

However, it remains unclear exactly how such health complications are linked to maternal smoking, London said. "Methylation might be somehow involved in the process," she said, adding that further studies are needed to confirm this idea.

Follow Sara G. Miller on Twitter @SaraGMiller. Follow Live Science @livescience, Facebook & Google+. Originally published on Live Science.

San Francisco's new tobacco ordinance — which raises the legal age to buy tobacco products from 18 to 21 — could help improve the health of a new generation of people by preventing addiction, health officials said.

Nationally, 18-year-olds can buy tobacco products, including cigarettes and cigars. However, in the past decade or so, some American communities, cities and one state (Hawaii) have passed ordinances and laws increasing the minimum age to 21.

These new policies could lead to better brain development among young adults who might have otherwise chosen to smoke at a younger age, said Brian King, the deputy director for research translation at the Centers for Disease Control and Prevention's Office on Smoking and Health. [10 Scientific Quit-Smoking Tips]

Research suggests that tobacco use, particularly nicotine exposure, can harm the developing human brain, King said. Moreover, the brain doesn't stop developing during the teenage years, but continues until about age 25, he said.

"There's an emerging body of evidence that has demonstrated that nicotine exposure can particularly harm the prefrontal cortex [of the brain] and lead to adverse health effects in the developing adolescent brain," King told Live Science. "And that can also continue into young adulthood."

The prefrontal cortex is involved with aspects of decision-making, cognition and memory, he added.

The new San Francisco ordinance, which is set to take effect June 1 and will also affect e-cigarettes, is also aimed at deterring people from smoking at an early age. About 90 percent of tobacco users begin before age 18, and the vast majority of the rest start before age 26, King said.

"If you can prevent use before the age of 18, you're preventing about 9 in 10 tobacco users," he said. "Then we don't have to help them quit, if we can prevent them from starting in the first place."

According to the 2009 Family Smoking Prevention and Tobacco Control Act, the Food and Drug Administration cannot raise the national age of purchasing tobacco products above age 18, King said. Congress could pass a bill increasing the age, but if it does not, any decision to set the age higher will have to come from individual states, cities and communities, he said.

However, it's not immediately clear how the San Francisco ordinance will affect smoking rates. New York City; Berkeley, California; Boston; and dozens of other cities and communities have increased the minimum buying age to 21, according to the Preventing Tobacco Addiction Foundation, but not enough time has passed in order to study the outcomes of these measures sufficiently.

The preliminary data  looks promising, King said. The city of Needham, Massachusetts, raised the buying age to 21 more than a decade ago, in 2005, and a recent survey of the region's youth showed that teenagers in Needham smoked less tobacco in the past 30 days than their peers in neighboring communities did.

That 2015 study, published in the journal Tobacco Control, showed that reported smoking rates dropped from 13 percent to 7 percent among teens in Needham from 2006 to 2010. This drop was larger than the 15 percent to 12 percent decrease seen in neighboring communities that did not raise the buying age, the researchers who conducted the study said. [Five Reasons Smoking Rules are Lax]

Furthermore, the decline was consistent for both genders and for Caucasian and non-Caucasian youth, the researchers reported.

In a March 2015 report, the Institute of Medicine estimated that if all states were to raise the minimum tobacco-buying age to 21, there would be a 12 percent drop in cigarette smoking prevalence across the nation by the year 2100, said King, who was not involved with the research.

"That would translate into nearly 250,000 fewer premature deaths from smoking," he said.

King added that raising the buying age is only one piece of the puzzle in the movement to stem tobacco use in youth and young adults. Policies to keep buildings or other areas smoke-free, media campaigns and better patient services are also helping to prevent or stop tobacco use, he said.

"Youth and young adults are particularly vulnerable to addiction for a variety of reasons," he said. "And so, preventing youth and young adults from starting in the first place could potentially prevent them from a lifelong addiction to tobacco products."

Follow Laura Geggel on Twitter @LauraGeggel. Follow Live Science @livescience, Facebook & Google+. Originally published on Live Science.

Nothing gets the Internet talking like viral cat videos, and now a new anti-smoking ad has tapped into people's love of funny cats in the name of health education — a move that experts say is a good one.

The ad, which aired during the Grammys this week, features a montage of beloved cat videos, from a feline riding a Roomba, to a kitty fake-playing a keyboard. But along with this cuteness comes an unexpected public health message: Smoking near your pet is hazardous to its health.

"Cats are twice as likely to get cancer if their owner smokes," proclaims a voice in the video, which was produced by a nonprofit organization called the Truth Initiative. "Smoking = no cats = no cat videos," the video warns. The ad encourages viewers to "Be the generation that ends smoking."

The ad generated a buzz on Twitter, with the hashtag "#catmageddon." Tobacco control and public health experts said they were pleased with the video.

"It's very clever," said Andrea Spatarella, a nurse practitioner at Northwell Health's Center for Tobacco Control in Great Neck, New York. Smokers with pets are often surprised to learn that a tobacco habit can affect animals too, she said.

The new video "may bring awareness to somebody that they're not only damaging their own heath, but [also] damaging the health of a pet they love dearly," Spatarella said. [Kick the Habit: 10 Scientific Quit-Smoking Tips]

And it's true that some studies show that cats exposed to secondhand smoke have double the risk of feline lymphoma, Spatarella said. Feline lymphoma is a cancer of a cat's lymph system, and is generally not curable.

Dr. Seema Yasmin, a public health professor and medical analyst for CNN, also tweeted, "This is how you do public health education. Look and learn #CATmageddon"

Although the video might not convince someone to quit right away, it may make smokers more likely to ask their health care providers about quitting, Spatarella said.

"It sparks the conversation, about smoking, about secondhand smoke and possibility about taking steps to quit," she said.

Follow Rachael Rettner @RachaelRettner. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

The percentage of young adults in the United States who smoke cigarettes has dropped in recent years, but the decline could be due to this population switching from cigarettes to other forms of tobacco, a new poll suggests.

The Gallup poll found that over the last decade, the smoking rate among 18- to 29-year-olds in the United States dropped 12 percentage points: from 34 percent of people in this age group smoking in 2001-2005 to 22 percent in 2011-2015.

In past years, young adults were more likely than people over 30 to smoke cigarettes, but now, the smoking rate among young adults is similar to the rate among people ages 30 to 49 and those ages 50 to 64, Gallup said. [The Drug Talk: 7 New Tips for Today's Parents]

However, another recent Gallup poll, conducted from January to October this year, found that young adults are more likely than those in older age groups to use alternative forms of tobacco, like cigars, pipes and smokeless tobacco.

For example, in the recent poll, 5.4 percent of 18- to 29-year-olds said they use smokeless tobacco (which includes products like chewing tobacco and snuff), compared with 4.3 percent of 30- to 49-year-olds and 2.8 percent of 50- to 64-year-olds. In addition, 4.1 percent of young adults said they smoked cigars, compared with 2.4 percent of 30- to 49-year-olds and 1.7 percent of 50- to 64-year-olds, the poll found.

Gallup started asking participants about alternative forms of tobacco only in 2014, and so the new poll cannot determine whether use of alternative forms of tobacco among young adults is increasing.

But an increase would agree with findings from other studies of tobacco use among young people. For example, a recent study from the Centers for Disease Control and Prevention found that between 2011 and 2014, the use of cigarettes among high school students declined, while the use of hookahs increased. (A hookah is a large pipe in which tobacco smoke passes through water before being inhaled.)

The Gallup poll also found that young people were more likely than people in other age groups to say they had used three or more forms of tobacco. Nearly 5 percent of 18- to 29-year-olds said they had used three or more forms of tobacco, about double the national average, of 2.5 percent.

Increased taxes and regulation on the sale of cigarettes may be one reason why young adults have turned to alternative forms of tobacco, Gallup said. Additionally, 2014 study found that young adults cited appealing flavors and the influence of friends as reasons why they tried alternative forms of tobacco, Gallup said.

Follow Rachael Rettner @RachaelRettner. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

The actress Mae West once said, "Too much of a good thing is wonderful!" Unfortunately, in reality, most of the decadent indulgences we pursue — including alcohol and rich foods — are not at all good for us, especially when taken in large quantities.

Now, a new study suggests that indulging in too much sleep and inactivity are also unhealthy. Researchers found that people who spend most of the day sitting and  sleeping too much may be as likely to die early as people who smoke or drink too much.

The Sax Institute's "45 and Up" study included more than 230,000 people in Australia ages 45 and older. For each participant, the researchers counted how many unhealthy behaviors he or she engaged in, including smoking, drinking alcohol, eating unhealthy foods, being physical inactive, exhibiting sedentary behaviors and sleeping too much (which the researchers defined as more than 9 hours per night). [7 Ways the Mind and Body Change With Age]

About 30 percent of the participants reported engaging in two or three of the behaviors. After six years, nearly 16,000 people in the study had died.

The researchers found that  people who were not physically active were 1.6 times more likely to die than those who were physically active (defined by the study as "undertaking more than 150 minutes of moderate-to-vigorous physical activity every week.")

But the study also showed that the combination of physical inactivity with sedentary behavior, or physical inactivity with too much sleep, were as strongly linked to mortality among the participants as the combination of smoking with heavy drinking.

"Physical inactivity alone had a strong association with mortality," Melody Ding, lead author on the study and senior research fellow at the Sydney School of Public Health, University of Sydney, told Live Science in an email.

And when people combined physical inactivity with long sleep times and extended periods of sitting, the negative effects were even more dramatic, with the combined risk for death increasing by up to four times as much as in those who were sedentary and slept too much, but at least got some exercise, Ding explained.

The researchers noted they did not incorporate other long-term lifestyle practices or conditions that might have played a part in increasing some participants' mortality risks. And the participants' interpretations of their own behaviors and its health impacts could have been faulty, skewing the study's results.

While the study's conclusion that healthier behaviors could reduce mortality risk seems like an obvious one, linking risky behaviors together could present new strategies for prolonging life.

"Physical activity is the one factor to address first," Ding said. If certain combinations of risk behaviors pose more of a threat than risk behaviors on their own, eliminating even one of them is a good choice for overall health.

The findings were published online Tuesday (Dec. 8) in the journal PLOS Medicine.

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Marijuana may raise people's risk of developing prediabetes, a condition in which blood sugar levels are abnormally high but not high enough to warrant a diagnosis with type 2 diabetes, a new study finds.

In the study, researchers found that people who used large amounts of marijuana during young adulthood were 40 percent more likely to develop prediabetes as middle-age adults than those who had never tried the drug.

However, marijuana use was not linked to an increased risk of having type 2 diabetes, according to the study, published today (Sept. 13) in the journal Diabetologia. [Marijuana vs. Alcohol: Which Is Worse for Your Health?]

Previous studies looking at marijuana use had found that users have lower rates of diabetes compared with nonusers, said Michael Bancks, a Ph.D. student at the University of Minnesota and lead author of the study. But in those studies, both marijuana use and diabetes were assessed at the time, meaning it was unclear whether people were using the drug before they developed diabetes, or afterward, he said.

"We felt we could address the potential limitations of previous research and add new information to our understanding of the relationship between marijuana use and subsequent metabolic health," Bancks told Live Science. Diabetes is a metabolic condition.

The results of the new study, however, contradict the results of previous studies that found that using marijuana may reduce the risk of developing diabetes, he said.

In addition, "it's unclear how marijuana use could place an individual at increased risk for prediabetes, yet not diabetes," the researchers wrote.

The researchers offered several reasons to explain this observation. For one, it's possible that people who were more likely to develop diabetes were left out of the study, because in order to be included, people had to be free of diabetes at the start of the follow-up period, the researchers wrote. It is also possible that marijuana may have a larger impact on blood sugar levels in the prediabetes range than the diabetes range, the researchers wrote.

Bancks said more research is needed to study the possible link, adding that researchers should look at different groups of people, how marijuana is consumed and the amount consumed, he said.

Still, Bancks encourages doctors to discuss the potential risks of using the drug with their patients. People who use marijuana should be informed that it may increase their risk of developing prediabetes, he said. And doctors should monitor the blood sugar levels of patients with "an extensive history of marijuana use," he said.

Marijuana use is on the rise, and other researchers are also taking a hard look at the health effects of the drug. In a 2014 review, researchers highlighted other health risks of marijuana, including an increased risk of cognitive impairment and psychoses.

Indeed, "there are many questions about the health effects of marijuana use where the answers are unknown," Bancks said. "The increased legalization and use of marijuana will draw more attention from researchers and users, and we will learn more as research on the health effects of marijuana use increases."

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Teens who use electronic cigarettes may be more likely to start smoking conventional tobacco products than teens who have never tried e-cigarettes, according to a new study.

Researchers looked at a group of teens who had just entered ninth grade in Los Angeles, and found that those who said they had used e-cigarettes — called vaping, because the nicotine solution is vaporized within the device — were more likely to report both six months and one year later that they had gone on to experiment with smokable tobacco products (such as cigarettes or cigars), compared with their classmates who hadn't tried vaping. 

"The study found that 14-year-olds who had used e-cigarettes for recreational purposes were four times more likely to start smoking at least one harmful tobacco product — including regular cigarettes, a hookah tobacco water pipe and/or cigars — over the next year," said Adam Leventhal, an associate professor of preventive medicine and psychology at the Keck School of Medicine of the University of Southern California in Los Angeles, and a co-author of the study, published today (Aug. 18) in The Journal of the American Medical Association (JAMA).

The new study showed a link between e-cigarette use in teens and an increased chance of smoking other products later on, but it did not establish a cause-and-effect relationship between them, Leventhal noted.

Still, the researchers said that although e-cigarette use in adults is viewed as a way to help regular smokers cut down or quit the habit, e-cig use in teens may play a very different role. [4 Myths About E-Cigarettes]

In the study, the researchers first surveyed about 2,500 ninth-graders in the fall at 10 public high schools in Los Angeles. The researchers included in their analysis only the students who reported they had never used any smokable tobacco products.

In a follow-up survey in the spring, about 31 percent of the ninth-graders who reported having used e-cigarettes at the beginning of the study said they had smoked cigarettes, cigars and/or hookah in the prior six months. Just 8 percent of the teens who had not used e-cigs said the same.

A similar trend was also observed when the teens were surveyed again, at the start of 10th grade, according to the findings.

Gateway to smoking

The report "is the strongest evidence to date that e-cigarettes might pose a health hazard by encouraging adolescents to start smoking conventional tobacco products," wrote Dr. Nancy Rigotti, director of the Tobacco Research and Treatment Unit at Massachusetts General Hospital in Boston, in an editorial accompanying the study, also published in the Aug. 18 issue of JAMA.

Rigotti called for prompt action to protect young people, such as proposed FDA regulations that would extend to e-cigarettes the same sales, marketing and use restrictions to e-cigarettes that currently apply to conventional tobacco products. These actions would include setting a minimum age of 18 for e-cigarette sales and requiring health warnings on packaging, and they might also include restricting e-cigarette advertising in youth-oriented media and banning product flavoring. 

E-cigarettes have become increasingly popular among teens. They may be drawn into recreational nicotine use because many of these devices are sleek-looking and high-tech, and minors can purchase them relatively easily, Leventhal told Live Science. He said their enticing flavors, like bubble gum, appeal to teens, who may also perceive e-cigarettes as less harmful than smokable tobacco.

In addition, teens who use e-cigarettes may enjoy the pleasurable effects of inhaling nicotine in an aerosol (i.e., vapor) form, Leventhal said. Those pleasurable effects may make teenagers more open to trying other products that provide inhaled nicotine, such as smokable tobacco products, he suggested.

Adolescence is a period when the brain is still developing and it is particularly sensitive to the effects of nicotine, Leventhal said. Plus, the teen years are a time when young people are likely to take risks, he said.

One limitation of the study, however, is that when teens were asked whether they had used any e-cigarettes or smokable tobacco products, they could give only a "yes" or "no" response. Therefore, the researchers were unable to measure whether students had a few puffs of a nicotine product or whether they were smoking them regularly and frequently.

Although regular-cigarette use among teens has been declining in the United States, the use of e-cigarettes, small cigars and hookah in this age group has either been on the rise or stable in recent years, Leventhal said. 

"A major concern is that the increasing population of adolescent e-cigarette users may eventually lead to future generations that smoke harmful tobacco products," Leventhal said.

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Young American women commonly smoke, but only very lightly, or they smoke on some days but not others, a new study finds.

Researchers analyzed information from more than 9,700 women ages 18 to 25, who answered questions about their smoking habits in 2011.

Overall, about 30 percent of the women were current smokers, whereas 28 percent were former smokers and 41 percent had never smoked. Most of the current smokers were "very light smokers," who smoked five or fewer cigarettes per day.

Nearly 20 percent of all women in the study, and more than 60 percent of the current smokers, were very light smokers, according to the findings.

In addition, more than 70 percent of the very light smokers said they didn't smoke every day. The very light smokers were more likely than heavier smokers to have some college education, and were more likely to perceive smoking as carrying higher health risks.

"Health educators and health care providers working with women in emerging adulthood need to recognize the high prevalence of very light smoking in this population, and screen for any level of tobacco use," the researchers, wrote in the July issue of the journal Preventing Chronic Disease. [Kick the Habit: 10 Scientific Quit-Smoking Tips]

In addition, some of the public health efforts aimed at getting people to quit smoking should be tailored to target very light smokers, the researchers said. People in this group may be less likely to identify themselves as smokers, but also more likely to recognize the high risks in smoking, the researchers said.

"Making very light smokers aware that even small amounts of tobacco are harmful would be important," study researcher Carole Holahan, of the Department of Kinesiology and Health Education at the University of Texas at Austin, told Live Science.

Even light smoking can carry health risks; very light smoking is linked with heart and lung problems, and an increased risk of cancer.

The study also found that very light smokers were more likely than nonsmokers to report depression and psychological distress. People in this group were also less likely to be married than any other group of smokers or nonsmokers.

Some people may become light smokers because they can't afford to buy a lot of cigarettes, the researchers said. Women in college, for example, may smoke at a light level because they attend parties on the weekend that promote smoking, study authors said. People may also start smoking lightly because of emotional stress, the researchers said.

Follow Rachael Rettner @RachaelRettner. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

Whether smoking marijuana contributes to weight gain may depend on how much pot a person smokes, in addition to other factors such the person's gender, according to a new study.

Smoking marijuana often gives people the munchies — a sudden increase in appetite that can make them eat a lot at once — so researchers wanted to examine whether this drive to eat might mean that people who smoke pot put on extra pounds over time.

The researchers looked at data from young people who had enrolled at age 12 or 13 in a 13-year study on nicotine dependence in teens. When they reached age 20, the 271 men and 319 women were asked whether they had smoked marijuana in the past year, and if so, how often they smoked. The participants were also asked if they smoked cigarettes. Researchers also tracked the participants' body mass indexes and waist size from ages 17 to 24.

The researchers found that, among the people in the study who smoked marijuana regularly but did not smoke cigarettes, the more often they smoked pot, the more weight they gained. For example, among the men in the study who did not smoke cigarettes, those who smoked marijuana daily gained more weight on average than the men who smoked pot weekly.

"The main finding of our study shows that long-term Cannabis use indeed influences weight gain," study co-author Didier Jutras-Aswad, a professor at the University of Montreal, said in a statement.

"But above all, we noted that certain factors drastically modify this effect," including gender, level of marijuana use and cigarette smoking, Jutras-Aswad said. [11 Odd Facts About Marijuana]

For example, among the men in the study, those who smoked both marijuana and cigarettes gained less weight on average than those who smoked marijuana but not cigarettes.

The reason for this finding may be that the nicotine in cigarettes tends to decrease a person's appetite, said study co-author Emily Dubé, a graduate student at the University of Montreal, told Live Science.

However, it turns out that the women in the study who smoked both marijuana and cigarettes did not gain any less weight than the women who smoked only marijuana.

The researchers don't know exactly why there may be this difference in how smoking marijuana and cigarettes may affect men's and women's weight, they said.

However, it may have something to do with how the THC in marijuana and the nicotine in cigarettes affect the body's control over hunger in men versus women, Jutras-Aswad said. "We also know that these targets in the brain are modified by hormonal factors that can fluctuate, in particular, during menstrual cycles," he said.

The study will be published in the August issue of the journal Pharmacology Biochemistry and Behavior.

Follow Agata Blaszczak-Boxe on Twitter. Follow Live Science @livescience, Facebook & Google+. Originally published on Live Science.

Larry Deutchman is executive vice president for marketing and entertainment industry relations and executive producer/writer for the PRISM Awards at the Entertainment Industries Council (EIC). Deutchman leads EIC's Let's Clear the Air Tobacco Awareness Campaign. He contributed this article to Live Science's Expert Voices: Op-Ed & Insights. 

Americans once saw smoking recommended by doctors and appearing in print, TV and radio advertisements. Major celebrities graced magazine tobacco advertisements —among them John Wayne, who later had a lung removed from a six-pack-a-day habit. Even Fred Flintstone and Barney Rubble had a relaxing smoke in TV commercials. 

However, according to the U.S. Centers for Disease Control and Prevention (CDC), Americans still see tobacco companies advertising their products in print, in-stores, or even through promotions in bars or clubs. In 2012, the CDC estimates, tobacco companies spent $9.6 billion in advertising and promotional expenses in the United States. 

Which message wins?

In place of smoking advertisements on TV, airwaves are now dominated by anti-smoking campaigns, which also blanket print, radio, and the internet to help decrease the rate of new smokers. For many years, we have been warned about the dangers of tobacco use and second-hand smoke. We know that smoking is the leading cause of preventable death in the United States, and that there are at least 28 chemicals in smokeless tobacco that have been to found to cause cancer. But, even with the education and smoking awareness campaigns, nearly 1 in 5 Americans still smokes cigarettes regularly, and the CDC has found there is a rise in the use of smokeless tobacco among young adults.

Nevertheless, the CDC has also found that from 2013 to 2014 there was a decline in tobacco product sales among adults, and the accurate depiction of the risks of tobacco use in entertainment media may have been a contributor to that decline. 

Tobacco is no longer the good guy

For example, a recent Lifetime TV movie called "A Day Late and a Dollar Short" was about a woman, played by Whoopi Goldberg, dying from lung cancer as a result of smoking. Other examples include an episode of the comedy series "Up All Night" in which Will Arnett's character tries to quit smoking for the sake of his infant, and a storyline on the daytime drama "The Bold and the Beautiful" featuring a longtime favorite character with lung cancer from smoking.

And yet positive images of tobacco use persist in the entertainment industry. Though the use of tobacco in television is not as prevalent as it once was, according to a study published in "Tobacco Control," we still see it turn up in shows such as "Mad Men," which is set in the 1960s when the image of people smoking was a huge part of culture and it was being jammed down people's throats (so to speak) by advertising agencies such as the one we see on the show. 

But in terms of major broadcast television networks, tobacco use is a lot less visible than it once was. In a recent study covering 56 years of prime-time drama television, University of Pennsylvania's Annenberg Public Policy Center found that tobacco use in television declined from a high of 4.96 instances per hour to .29 instances an hour between 1955 and 2010. While the study was able to show a relation between smoking reduction and screen-based media, it is important to note that cable shows, like AMC's Mad Men, were not included in the study and that only broadcast television shows were studied. 

For example, in the NBC television adaptation of DC Comics' "Hellblazer," the main character, John Constantine, does not smoke despite the fact that in the comics a key part of Constantine's character is that he is a chain-smoker with cancer. Such changes in tobacco use on television, from a character whose key trait is chain-smoking to one who never touches a cigarette, could help further the changes already made in real-world smoking habits. 

The sweet spot

As Deputy U.S. Surgeon General Boris Lushniak said about smoking, "I know the group I have to emphasize, I know it's gotta be the age of 12 to the age of 26. If I can influence that part of our population, it's only 14 years, and have them make an empowered decision with all of the social media information, to say 'I know there's peer pressure. I know some people say this is cool. But at the end of the day, I'm actually smart enough to make the decision, and I'm gonna put this [cigarette] down." The combination of entertainment media and social media can make the difference when it comes to smoking trends in teens and young adults.

General awareness of smoking can be further reinforced by spotlighting the downside of tobacco use , including long-term health risks such as emphysema, emphysema or cancer. Uniquely the cosmetic effects of smoking, such as yellowing teeth and premature facial wrinkling put realities of smoking right in your face, so to speak, although campaigns using this latter approach have not proven as successful at discouraging young people from starting to smoke. [E-Cigarettes May Lure Teens into Traditional Smoking]

Encouraging the entertainment industry to show continued diligence to deglamorize tobacco when crafting storylines and creating characters supports accuracy in storytelling. Clearly, tobacco use is not a trait without its share of consequences. The repercussions of smoking can range from superficial to life changing. 

For more suggestions on accurately depicting tobacco use or other substances, check out the Entertainment Industries Council’s (EIC) Depiction Suggestion Book. 

Follow all of the Expert Voices issues and debates — and become part of the discussion — on Facebook, Twitter and Google+. 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.

Smoking may bring on changes in cells that are linked with many cancers, including breast and gynecological cancers, a new study finds. These changes could provide an early warning sign of cancer, particularly in cheek cells, the research showed.

Researchers analyzed cheek swabs from 790 women, and found those who smoked were more likely to have certain changes associated with these cancers, which people may not realize are linked with smoking.

The researchers were looking for epigenetic changes in cells, which are changes in the complex system of chemicals and proteins that attach to DNA and turn genes on and off. Such changes are associated with cancer development and can be caused by exposure to environmental factors such as cigarette smoke.

"Our work shows that smoking has a major impact on the epigenome of normal cells that are directly exposed to the carcinogen," lead author Andrew Teschendorff, a research fellow at the University College London (UCL) Cancer Institute, said in a statement. "This research gets us closer to understanding the very first steps" in cancer's development, he said. The epigenome is network of chemical compounds around DNA that regulates the activity of genes.

The study findings could lead to better ways to predict people's risk of cancer, or to detect it early, Teschendorff said.

Environmental factors, such as smoking, can disrupt a cell's epigenome, eventually leading to the out-of-control cell growth seen in cancer, the researchers said.

In the study, the researchers analyzed the epigenetic changes within cells, and found a "signature" of smoking. By looking for this signature, the researchers found they could differentiate between normal and cancerous tissue with near absolute certainty, including cancers in other parts of the body.  [Kick the Habit: 10 Scientific Quit-Smoking Tips]

The signature could also be used to predict if a pre-cancerous lesion would progress to a full-blown invasive cancer, the researchers said.

The ability to quickly and easily identify such changes in cells could help doctors to predict and prevent cancers, the researchers said.

The researchers also found that cheek cells may be a better indicator of a woman's epigenetic changes than her blood cells. The cheek cells showed a 40-fold increase in abnormal genetic activities, compared with the blood samples taken from the same people.   

"These results pave the way for other studies in which easily accessible cells can be used" to look for epigenetic changes that may indicate a person's cancer risk, said the study's senior author Dr. Martin Widschwendter, of UCL's Institute for Women's Health.

"This is incredibly exciting for women's cancers such as ovary, breast and endometrial cancer, where predicting the cancer risk is a big challenge," Widschwendter said in a statement.

The researchers noted that because the study included only samples from women, it is unclear if the findings apply to men. Although previous epigenetic studies using blood samples have suggested that most smoking-related changes are independent of sex, only further research can prove if that holds true for cheek cells as well.

The study was published May 14 in the journal JAMA Oncology.

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