In a new report, researchers from the U.S., Canada, and Australia analyze 54 studies that linked how much people drink with risk of premature death from all causes, including heart disease. Researchers from the University of Victoria in British Columbia and the University of California, San Francisco led the team.
The researchers investigated a suggestion put forth in the scientific community 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 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 reflect the poor health of some abstainers who recently quit drinking rather than indicating a protective effect for alcohol.
The team found only seven studies that included only long-term non-drinkers in the "abstainers" group. The results of the seven studies showed no reduction in risk of death among the moderate drinkers compared with abstainers. When the researchers combined the 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, published online in advance of the May 2006 issue of Addiction Research and Theory, 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.