A new study debunks claims that moderate drinking has some health benefits.
In this analysis, researchers examined 87 previously conducted studies that had explored the effects of drinking alcohol in moderation. They found that due to flaws in many of the studies' designs, the evidence that suggests alcohol can be healthy to a certain extent might not be too reliable.
Lead researcher Tim Stockwell, the director of the University of Victoria's Center for Addictions Research in British Columbia, Canada, said one of the most common mistakes was how the researchers categorized an "abstainer." In many of the studies, the researchers had compared moderate drinkers, defined as having up to two drinks or one to three drinks per day, to current abstainers, defined as people who did not drink. The researchers had not, however, factored in the abstainers' history of alcohol use or reasons behind abstinence, which could both affect the results. For example, abstainers could have avoided alcohol due to health issues.
"A fundamental question is, who are these moderate drinkers being compared against?" Stockwell asked.
Stockwell and colleagues then corrected these types of issues as well as some parts of the studies' design and found that moderate drinking was no longer associated with living a longer life.
"We saw a change from this famous J-shape curve suggesting moderate drinking is good for health to the J-shape curve vanishing. So abstainers and low-volume, occasional drinkers were all pretty similar in terms of risk from dying of any causes," Stockwell said.
Stockwell noted that in the 13 studies that did not have this abstainer bias, the researchers had not found an association between moderate drinking and longevity.
"There's a general idea out there that alcohol is good for us, because that's what you hear reported all the time," Stockwell said. "But there are many reasons to be skeptical."
The researchers noted that other factors could be contributing to improved health in moderate drinkers. Researcher Timothy Naimi pointed out that moderate drinkers tend to be healthier because they are more likely to be social and educated individuals. The researchers stated that a study that factors in potentially confounding variables would most likely yield a better understanding of the effects of moderate drinking.
The findings from the analysis were published in the Journal of Studies on Alcohol and Drugs.
