A new study assesses the reliability of studies suggesting the benefits of moderate drinking (Photo: Reuters)
Studies suggesting that moderate alcohol consumption increases life expectancy and lowers the risk of heart disease and chronic disease compared with abstainers are based on “flawed scientific research”, a new study has found.
These studies have been published for many years, contributing to the widespread belief that alcohol is healthy when consumed in moderation – one drink a week to two drinks a day.
The researchers found that these studies mostly focused on moderate drinking among older adults and compared them to “abstainers” or “occasional drinkers,” both groups of which included older adults who had stopped drinking or cut down on their drinking due to health problems.
“In comparison, people who continue to drink alcohol appear to be much healthier,” said lead researcher Tim Stockwell, a scientist at the Canadian Substance Use Research Institute at the University of Victoria.
The study therefore “suffers from a fundamental design flaw” because it doesn’t take into account people’s lifetime drinking habits, the authors say. The findings are published in the Journal of Alcohol and Drug Research.
“There is no completely ‘safe’ level of alcohol consumption,” Stockwell says.
The research team identified 107 published studies that looked at the relationship between drinking habits and longevity.
When all the data was combined, light-to-moderate drinkers had a 14% lower risk of death during the study period compared with abstainers, the researchers said.
But looking more closely at all the data, “higher quality” studies that analyzed the drinking habits of people under the age of 55 on average, and made sure former and occasional drinkers weren’t counted as “abstainers”, found that moderate drinking was not associated with a longer lifespan.
“As expected, when examining former drinkers, occasional drinkers and abstainers separately in the younger cohort, we found similar mortality risk estimates between light drinkers and abstainers,” the authors write.
Instead, the authors say, most of the studies linking moderate drinking to longevity came from “low-quality” studies in older adults that did not distinguish between former drinkers and lifetime abstainers.
“If you look at the weakest studies, you see health benefits,” Stockwell said.
Because of this bias in sample selection, the studies could produce misleading associations between drinking alcohol and health benefits, “which could confound communication about health risks,” the authors say.
The relationship between moderate alcohol intake and health benefits was first reported in 1926 by American biologist Raymond Pearl in his book Alcohol and Longevity. In recent years, several studies have shown that there is no such thing as a “safe amount of alcohol intake.”
In January 2023, the World Health Organization (WHO) published a statement in the Lancet Public Health journal stating, “There is no safe amount of alcohol consumption that will not have adverse health effects.”
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