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Investigators at New York Presbyterian Hospital, Columbia Presbyterian campus, have determined that moderate alcohol consumption by the elderly—up to two drinks per day—reduces the risk of the most common type of stroke. The results of the case-control study, funded by the National Institute of Neurological Disorders and Stroke, are to be published in the upcoming January 6 issue of the Journal of the American Medical Association (JAMA).

The study is the first to examine the relationship between alcohol and stroke risk among the elderly of three different racial/ethnic groups—Caucasians, African-Americans, and Hispanics. "Many studies have shown that moderate alcohol consumption protects against cardiac disease, but until now, its relationship with stroke risk was less certain. Our study provides the first important evidence that moderate alcohol use is associated with a significantly decreased risk of ischemic stroke in a multiethnic, urban, elderly population," notes Ralph L. Sacco, M.D., M.S., Associate Professor of Neurology and Public Health at the Gertrude H. Sergievsky Center at Columbia Presbyterian.

Previous studies have suggested that moderate alcohol consumption protects against ischemic stroke (where a blood clot blocks a blood vessel in the brain) in certain populations, while other studies have found no beneficial effect. It has also been speculated that the relationship between alcohol and stroke risk varies according to race/ethnicity, as studies in Caucasian populations have found alcohol to have a protective effect, while those in Asian populations have not. Studies of African-American populations have yielded conflicting results, while prior to the Columbia Presbyterian investigation, no study had addressed the relationship between alcohol and stroke among Hispanics.

The study examined data from the Northern Manhattan Stroke Study (NOMASS), one of the first population-based studies to compare stroke incidence among Caucasians, African-Americans and Hispanics living in the same community. Over four years, 677 patients with ischemic stroke were matched by age, sex, and race/ethnicity with subjects who had never suffered a stroke. The mean age of the study population was 70.

The case-control analysis showed moderate daily alcohol use in the preceding year was protective against ischemic stroke, even after adjustment for hypertension (high blood pressure), diabetes, cardiac disease, current smoking, education, and body mass index. "We found this protective effect no matter what type of alcohol was consumed, whether it was wine, beer, or liquor. This is in accord with the majority of studies of the protective effect of alcohol on coronary artery disease," observes Dr. Sacco.

The study showed that heavy alcohol consumption—seven or more drinks per day—was associated with increased stroke risk. But former heavy drinkers who decreased their consumption to no more than two drinks per day were able to reduce their risk. While the protective effect of alcohol on heart disease appears to be at least partially related to levels of high-density lipoprotein (HDL, or the so-called good cholesterol), the relative importance of HDL in mediating alcohol's effect on stroke risk has not been well studied.

Data from the Columbia Presbyterian study suggest that the protective effect of alcohol was independent of HDL. "While no study has shown a benefit in recommending alcohol use to people who don't drink, our data support the view, endorsed by the National Stroke Association in its Stroke Prevention Guidelines, that among those who are moderate drinkers, continued consumption may provide a reduction of ischemic stroke risk," says Dr. Sacco. "These benefits, of course, must be weighed against the overall risk of morbidity and mortality due to excess alcohol consumption."