Harmful Cocktail: Alcohol Plus Energy Drinks May Raise Injury Risk

People who mix alcohol with energy drinks may be at a greater risk of getting hurt while they are intoxicated than those who drink alcohol by itself, a new review of earlier studies suggests.

The researchers reviewed information from 13 previous studies conducted from 2008 to 2015. These studies involved people who consumed alcohol with energy drinks, or alcohol alone.

In 10 of the studies, the people who consumed alcohol with energy drinks had a greater risk of getting injured, compared with those who consumed alcohol alone. These injuries included motor vehicle accidents, falls or other injuries sustained while intoxicated, including injuries from fights.

For example, a 2015 study included in the review found that high school students who consumed alcohol with energy drinks were four times more likely to have a motor vehicle accident after drinking, compared with those who consumed alcohol by itself. Another study, conducted in 2014, found that teens who mixed alcohol with energy drinks were four times more likely to engage in fighting and five times more likely to sustain an alcohol-related injury, compared with those who consumed alcohol alone. [7 Ways Alcohol Affects Your Health]

It's thought that the caffeine in energy drinks may somewhat mask the sedative effects of alcohol, the researchers said. "Usually when you're drinking alcohol, you get tired and you go home," Audra Roemer, a research assistant at The University of Victoria in British Columbia, Canada, said in a statement. "Energy drinks mask that, so people may underestimate how intoxicated they are, end up staying out later, consume more alcohol, and engage in risky behavior and more hazardous drinking practices."

However, the studies included in the review had several limitations, and so more research is needed to confirm the results. All of the studies were conducted at a single point in time, and some of the studies did not specifically ask people to report injuries that occurred after drinking alcohol mixed with energy drinks. Rather, these studies asked people if they consumed alcohol with energy drinks, and then asked them in a separate question to report injuries that occurred after drinking. This means the researchers cannot prove that the mix of alcohol and energy drinks actually caused the higher risk of injury.

In addition, some studies suggested that another factor could underlie both people's consumption of energy drinks and their risk of injury. For example, people who are more impulsive or tend to take more risks are also more likely to consume alcohol with energy drinks, and it's not clear exactly how much this risk-taking tendency contributes to the increased risk of injury seen in the review.

What's more, because the studies included in the review varied widely in how they were conducted, the researchers could not pool the results to estimate the extent of the injury risk, they said.

The researchers involved in the new review are now conducting another study using information from emergency-department visits to better understand the link between consuming alcohol mixed with energy drinks and the risk of injury.

"Hopefully, that will bring more answers," Roemer said.

The review is published in the March issue of the Journal of Studies on Alcohol and Drugs.

Original article on Live Science.