Cardioprotection from Moderate Drinking Is Limited to People with Unhealthful Behaviors
Nonsmokers who ate healthful diets and exercised didn't benefit from alcohol.
In observational studies, researchers have found an association between moderate drinking and lower risk for myocardial infarction, but less is known about whether this benefit is limited to select groups. Researchers in London prospectively followed 9655 middle-aged adult civil servants (mean age, 44; none with known MI at enrollment) for a median of 17 years.
Subjects were characterized according to number of unhealthful behaviors (smoking, lack of exercise, poor diet). Among people who reported regular physical activity, daily fruit and vegetable consumption, and no smoking, alcohol use had no effect on incidence of fatal coronary heart disease or nonfatal MI in analyses that were adjusted for age, sex, and socioeconomic status. Among participants with two or three unhealthful behaviors, moderate alcohol intake (8–112 g, or about 1–9 standard U.S. drinks weekly) was associated with half the risk for CHD; in addition, adjusting for diabetes, angina, hypertension, and cardiovascular medication use yielded similar results.
Even if moderate drinking lowers risk for CHD (a hypothesis that has not been confirmed yet in clinical trials), alcohol ingestion appears to have no such benefit for people who exercise, eat fruits and vegetables, and do not smoke. The authors cite one large cohort study, done in the U.S., with similar results. Therefore, they recommend that this typically overlooked variability in the effect of moderate drinking be emphasized in public health messages and advice about alcohol use. Such a message — which would acknowledge potential benefits among people with certain unhealthful behaviors — also would emphasize lack of benefit in others and the importance of healthful behaviors. The message is complicated further by the lack of controlled trials, by research that suggests benefits accrue mainly to those with genetic predispositions to alcoholism, and by harms associated with moderate drinking (e.g., excess risk for certain cancers).
Richard Saitz, MD, MPH, FACP, FASAM
Published in Journal Watch General Medicine December 18, 2008
Britton A et al. Who benefits most from the cardioprotective properties of alcohol consumption — Health freaks or couch potatoes? J Epidemiol Community Health 2008 Oct; 62:905.