For the regular boozer it is a source of great comfort: the fat pile of studies that say a daily tipple is better for a longer life than avoiding alcohol completely.
But a new analysis challenges the thinking and blames the rosy message on flawed research that compares drinkers with people who are sick and sober.
Scientists in Canada delved into 107 published studies on 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 cut down or quit through ill health.
The finding means that amid the abstainers and occasional drinkers are a significant number of sick people, bringing the group’s average health down, and making light to moderate drinkers look better off in comparison.
“It’s been a propaganda coup for the alcohol industry to propose that moderate use of their product lengthens people’s lives,” said Dr Tim Stockwell, first author on the study and a scientist at the Canadian Institute for Substance Use Research at the University of Victoria.
“The idea has impacted national drinking guidelines, estimates of alcohol’s burden of disease worldwide and has been an impediment to effective policymaking on alcohol and public health,” he added. Details are published in the Journal of Studies on Alcohol and Drugs.
Many studies on the health impact of alcohol show a J-curve effect, where death rates are lowest among those who drink a little. When the Canadian team combined the data from the studies in their analysis, it suggested that light to moderate drinkers – those having between one drink a week and two a day – had a 14% lower risk of dying over the study period compared with abstainers.
But the apparent benefit evaporated on closer inspection. In the highest-quality studies, which included younger people and made sure that former drinkers and occasional drinkers were not considered abstainers, there was no evidence that light to moderate drinkers lived longer. That was only seen in the weaker research that failed to separate former drinkers and lifelong teetotallers.
“Estimates of the health benefits from alcohol have been exaggerated while its harms have been underestimated in most previous studies,” Stockwell said.
“The great majority of previous studies compare drinkers with an increasingly unhealthy group of people who currently abstain or drink very little. We know people give up or cut down on drinking when they become unwell and frailer with age. The most biased studies included many people who had stopped or cut down their drinking for health reasons in the comparison group so making people well enough to continue drinking appear even healthier,” he added.
England’s former chief medical officer, Dame Sally Davies, has said there is no safe level of alcohol intake. A major study published in 2018 supported the view. It found that alcohol led to 2.8 million deaths in 2016 and was the leading risk factor for premature death and disability in 15- to 49-year-olds. Among the over 50s, about 27% of global cancer deaths in women and 19% in men were linked to their drinking habits.
Despite the growing evidence for harm at even low levels, adults in the UK are advised to keep the risk down by not drinking more than 14 units a week. Half a pint of average-strength lager contains one unit and a 125ml glass of wine contains about 1.5 units.
Last year, a major study of more than half a million Chinese men linked alcohol to more than 60 diseases, including liver cirrhosis, stroke, several gastrointestinal cancers, gout, cataracts and gastric ulcers.
“Studies of alcohol and health can be subject to biases, even when they are well-conducted,” said Dr Iona Millwood at the University of Oxford, a co-author on the study of Chinese men. “This is because drinking patterns tend to 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.”
