Regular drinkers often find solace in numerous studies suggesting that a daily drink may extend life more than abstaining completely. However, a new analysis disputes this, attributing the optimistic outlook to flawed research comparing drinkers with those who are sick and sober.
Canadian scientists examined 107 studies on drinking habits and lifespan. They discovered that many studies compared drinkers to abstainers without considering that some abstainers had reduced or quit alcohol due to health issues. This oversight means that the abstainer group included many unhealthy individuals, skewing results to favor light to moderate drinkers.
Dr. Tim Stockwell, the study’s lead author and a scientist at the Canadian Institute for Substance Use Research at the University of Victoria, explained, “It’s been a propaganda coup for the alcohol industry to suggest that moderate use of their product extends life.” He added that this belief has influenced national drinking guidelines, global estimates of alcohol’s health impact, and hindered effective alcohol and public health policies. The study’s findings are published in the Journal of Studies on Alcohol and Drugs.
Many studies show a J-curve effect, where death rates are lowest among light drinkers. However, the Canadian team’s combined data suggested that light to moderate drinkers had a 14% lower risk of dying over the study period compared to abstainers. This perceived benefit disappeared upon closer examination. High-quality studies that excluded former and occasional drinkers from the abstainer group showed no evidence that light to moderate drinkers lived longer. The longevity benefit was only seen in weaker studies that did not make this distinction.
“Estimates of the health benefits from alcohol have been exaggerated while its harms have been underestimated in most previous studies,” Stockwell said. He noted that many studies compared drinkers with unhealthy individuals who abstained or drank very little, often because they were unwell or frail. This bias made those who continued drinking appear healthier by comparison.
Dame Sally Davies, England’s former chief medical officer, has asserted that no level of alcohol intake is safe. A major 2018 study supported this, finding that alcohol caused 2.8 million deaths in 2016 and was the leading risk factor for premature death and disability among 15- to 49-year-olds. Among those over 50, alcohol was linked to 27% of global cancer deaths in women and 19% in men.
Despite evidence of harm even at low levels, UK adults are advised to limit drinking to 14 units per week. Half a pint of average-strength lager equals one unit, and a 125ml glass of wine contains about 1.5 units.
A recent study of over half a million Chinese men linked alcohol to more than 60 diseases, including liver cirrhosis, stroke, several cancers, gout, cataracts, and gastric ulcers.
Dr. Iona Millwood at the University of Oxford, a co-author of the Chinese study, commented, “Studies of alcohol and health can be biased, even when well-conducted. Drinking patterns often correlate with factors like smoking and socioeconomic status, and people change their drinking habits in response to poor health. Increasing evidence suggests the apparent benefits of moderate drinking are unlikely to be causal.”
