Some of the association between moderate alcohol consumption and longer life is explained by the fact that teetotallers are less wealthy, less educated and more likely to be disabled, according to a new US study.
Dr Sei Lee and colleagues of San Francisco VA Medical Centre found one drink per day halved your risk of dying over the next four years, Reuters reports.
Even taking into account several other factors that may affect mortality and alcohol consumption, moderate drinkers were still 28% less likely to die than those who abstain.
However, 86 years after the first study showed moderate drinkers live longer, it is yet to be determined whether moderate drinkers are just healthier in general than non-drinkers, or if alcohol itself has beneficial health qualities, the study said.
Dr Lee’s study investigated two key risk factors that don’t appear to have been studied together before - socioeconomic status (SES) and functional disability.
Of the 12,519 men and women aged 55 and older they looked at over four years, more non-drinkers died than moderate or heavy drinkers, with 14% of non-drinkers dying, 12% of those who consumed three or more drinks daily, and 7% of moderate drinkers dying.
Those who had one drink per day had significantly higher socioeconomic status than teetotallers according to Dr Lee & colleagues. Only 14% of non-drinkers had a university education compared to 37% of drinkers, while 21% of teetotallers had assets of $300,000 compared to 52% of drinkers.
Non-drinkers were also more likely to have difficulties looking after themselves with activities like going to the toilet or getting dressed, let alone problems with complicated matters like managing their finances or cooking.
Eighteen percent of moderate drinkers had trouble walking several blocks, compared to 41% of teetotallers.
A report of the study in the June Journal of the American Geriatrics Society found drinkers were overall half as likely to die as the non-drinkers.
Even after adjusting for usual risk factors like illness, obesity, and smoking, moderate drinkers were still 43% less likely to die during follow up, and even adding in disability and socioeconomic status showed moderate drinkers were 28% less likely to die than non-drinkers.
"The results significantly strengthen the evidence that moderate drinking leads to lower rates of overall mortality," the researchers said.
However, moderate drinkers could have yet more beneficial characteristics not examined in the study, and it's possible "that adjustment for these characteristics could fully explain the alcohol-mortality relationship."
Whether or not moderate drinking is in itself beneficial to health is a question that can only answered by a randomised, controlled trial, the researchers said.
Such a trial would present serious "logistical and ethical" hurdles, but given the lack of consensus on the overall pluses and minuses of moderate alcohol use, "the time has come to perform such a trial" they concluded.