For the average drinker, it’s a source of great comfort: the many studies showing that a daily sip is better for a longer life than avoiding alcohol altogether.
But a new analysis challenges this thinking, blaming the rosy message on flawed research comparing drinkers to sick and sober people.
Scientists in Canada dug into 107 published studies of people’s drinking habits and how long they lived. In most cases, they found that drinkers were compared with people who abstained or consumed very little alcohol, without taking into account that some had quit or cut back because of poor health.
The finding shows that there is a significant number of illnesses among teetotalers and occasional drinkers, which reduces the average health of the group and makes light to moderate drinkers appear to be better off in comparison.
“It is a propaganda stunt by the alcohol industry to claim that moderate use of their product extends people’s lifespan,” said Dr. Tim Stockwell, lead author of the study and a scientist at the Canadian Institute for Substance Use Research at the University of Victoria.
“The idea has influenced national drinking guidelines, estimates of the global burden of disease from alcohol and has been a barrier to effective alcohol and public health policies,” he added. Details are published in the Journal of Alcohol and Drug Studies.
Many studies on the health effects of alcohol show that: J-curve effectwhere death rates are lowest among those who drink lightly. When the Canadian team combined the data from the studies in their analysis, it suggested that light to moderate drinkers – those who had between one drink a week and two a day – had a 14% lower risk of dying over the study period compared with teetotalers.
But the apparent advantage disappeared on closer inspection. In the highest-quality studies, which included younger people and made sure that former drinkers and occasional drinkers were not counted as abstainers, there was no evidence that light to moderate drinkers lived longer. That was only seen in the weaker studies that failed to separate former drinkers from lifelong abstainers.
“Estimates of the health benefits of alcohol have been exaggerated, while its harmful effects have been underestimated in most previous studies,” Stockwell said.
“The vast majority of previous studies compare drinkers with an increasingly unhealthy group of people who currently do not drink at all or drink very little. We know that people stop drinking or cut down on drinking as they become sicker and frailer with age. The most biased studies included many people who had stopped or cut down on drinking for health reasons in the comparison group, making people who were healthy enough to continue drinking look even healthier,” he added.
England’s former chief medical officer, Dame Sally Davies, has said that there is no safe level of alcohol intake. A major review published in 2018 supported this view. It found that alcohol caused 2.8 million deaths in 2016 and was the leading risk factor for premature death and disability in 15- to 49-year-olds. Among those aged 50 and over, around 27% of global cancer deaths in women and 19% in men were linked to drinking.
Despite mounting evidence of harm even at low levels, adults in the UK are advised to keep their risk low by not drinking more than 14 units per weekHalf a pint of medium strength lager contains one unit and a 125ml glass of wine contains about 1.5 units.
Last year, a higher education of the more than half a million Chinese men, alcohol was linked to more than 60 diseases, including liver cirrhosis, stroke, various forms of gastrointestinal cancer, gout, cataracts and stomach ulcers.
“Studies on alcohol and health can be subject to bias, even when they are well done,” said Dr. Iona Millwood of the University of Oxford, a co-author of the study of Chinese men. “This is because drinking patterns often correlate with other factors, such as smoking and socioeconomic status, and people often change their drinking patterns in response to poor health. We are seeing increasing evidence that the apparent beneficial health effects of moderate drinking are unlikely to be causal.”