Daily low or moderate alcohol intake is not associated with all-cause mortality risk, found the new research review and meta analysis of 107 studies involving more than 4.8 million participants that was published recently in the journal Jama Open Network.
Researchers, including those from the University of Victoria in Canada, found instead that there was an increased risk of death evident at higher consumption levels, starting at lower levels for women than men.
“The proposition that low-dose alcohol use protects against all-cause mortality in general populations continues to be controversial,” scientists wrote in the study.
While previous observational studies had suggested that “moderate drinkers” have longer life expectancy, and are less likely to die from heart disease than abstainers, researchers said these associations may be due to systematic biases that affect many studies.
These previous studies identified only associations between factors, but can be misleading as they do not prove cause and effect, scientists pointed out.
In the new study, controlling for several factors such as median age and sex of the cohorts, they did not find any significant reductions in risk of all-cause mortality for drinkers who drank less than 25g of ethanol per day – which is less than two standard cocktails.
“There was a significantly increased risk of all-cause mortality among female drinkers who drank 25 or more grams per day and among male drinkers who drank 45 or more grams per day,” scientists said.
The new analysis found that moderate drinkers included in the previous studies tended to be wealthier, more likely to exercise and eat a healthy diet, and less likely to be overweight.
Citing some of the limitations of the analysis, they said most of the assessed studies had imperfect measurement of alcohol consumption.
The self-reported alcohol consumption analysed in many of the included studies tends to be underreported.
Scientists concluded that the new analysis “did not find significantly reduced risk of all-cause mortality associated with low-volume alcohol consumption after adjusting for potential confounding effects”.
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