International study questions health
benefits of moderate drinking

The majority of studies suggesting that ‘moderate’ drinking helps prevent heart disease may be flawed, according to an international research group. In a new report, researchers from the U.S., Canada, and Australia analyse 54 studies thatlinked how much people drink with risk of premature death from all causes, including heart disease.

‘Sick quitters’

The researchers investigated a suggestion put forth by scientific skeptics of the ‘alcohol protects against heart attacks’ theory, that many of the studies conducted so far on drinking and premature death made a consistent and serious error by including as ‘abstainers’ people who had actually cut down or quit drinking due to declining health, frailty, medication use or disability. When such studies show a higher death rate for abstainers than for moderate drinkers, this result may reflectthe poor health of some abstainers who recently quit drinking rather than indicating a protective effect for alcohol.

The authors credit British researcher Professor Gerry Shaper of the Royal Free and University College Medical School in London, for first proposing the possibility of an 'abstainer error’ in the design of prospective studies of the association between alcohol use and heart disease risks. The new study supports Professor Shaper’s conclusion that while the known biological effects of alcohol on risk factors for coronary heart disease are of scientific interest, they have limited significance for public health.

The team found just seven studies that included only longterm non-drinkers in the ‘abstainers’ group. The results of these seven studies showed no reduction in risk of death among the moderate drinkers compared with abstainers. When the researchers combinedthe data from these studies, they showed that it was possible to perform new analyses that appeared to show a protective effect of moderate drinking – but only when they deliberately included the error of combining long-term abstainers with people who had cut down or quit drinking more recently.

The authors caution that their report has not disproved the notion that light drinking is good for health, as too few error-free studies have been performed. They suggest, however, that the extent to which these benefits actually translate into longer life may have been exaggerated.

“The widely-held belief that light or moderate drinking protects against coronary heart disease has had great influence on alcohol policy and clinical advice of doctors to their patients throughout the world,” said Tim Stockwell, PhD, of the Centre for Addictions Research at the University of Victoria. “These findings suggest that caution should be exerted in recommending light drinking to abstainers because of the possibility that this result maybe more apparent than real.

“We know that older people who are light drinkers are usually healthier than their non-drinking peers,” said Dr Kaye Fillmore of the UCSF School of Nursing. “Our research suggests light drinking is a sign of good health, not necessarily its cause. Many people reduce their drinking as they get older for a variety of health reasons.”

The authors emphasize that there is a need for more well designed research in the future that assesses people’s alcohol intake and abstinence more precisely as their drinking patterns change with age.

Moderate alcohol use and reduced mortality risk: Systematic error in prospective studies. Kaye Middleton Fillmore, William C. Kerr, Tim Stockwell, Tanya Chikritzhs, & Alan Bostrom. Addiction Research and Theory 2006. Published online.