Ischemic and hemorrhagic strokes are a leading cause of morbidity and mortality in the United States as well as in other countries. The major risk factors for stroke are similar to those for coronary artery disease and include hypertension, diabetes and elevated cholesterol levels. Interventions to control risk factors have been shown to protect against stroke. One modifiable risk factor that has been discussed extensively in the literature over the past few years is alcohol consumption. A number of published studies have suggested that low-to-moderate amounts of alcohol reduce the risk of heart attack and ischemic stroke. Berger and colleagues recently reported data from the Physicians Health Study that examined the associations between stroke and alcohol consumption among a cohort of white male physicians.
The Physicians Health Study was a randomized, double-blind, placebo-controlled trial that examined the benefit of low-dose aspirin on the risk of cardiovascular disease. This portion of the study was terminated early (January 1988) because of the significant reduction of first myocardial infarction. The study also examined the potential benefit of beta carotene in preventing cancer, and this portion of the study concluded as scheduled in December 1995. The report on alcohol consumption includes data from October 1995 when study participants had been followed an average of 12.2 years. More than 22,000 white male physicians from the United States, between the ages of 40 and 84 at the start of the study, were enrolled, beginning in 1982. Baseline data were obtained from all participants on health history and lifestyle issues (including tobacco use and alcohol consumption). Alcohol consumption was quantified as none, one to three drinks per month, one drink per week, two to four drinks per week, five or six drinks per week, one drink per day, or more than one drink per day. The participants were mailed questionnaires every six months to assess compliance with aspirin and beta carotene therapy during the active treatment arms of those portions of this study. The participants also provided updates on any newly diagnosed medical conditions, including stroke or transient ischemic attack. Alcohol consumption was reassessed at year 7 of the study.
Because only 674 physicians reported consuming alcohol two or more times daily, this group was combined with the group that reported consuming one drink per day. These two combined groups represent the high-consumer group. Study participants who drank from none to rarely to three times per month were also combined into one group for statistical purposes.
During 12 years of follow-up, 679 first strokes were reported. This included 557 ischemic strokes, 88 hemorrhagic strokes and 34 listed as unknown. After adjusting for systolic blood pressure, smoking, diabetes and exercise, it was noted that the participants who consumed one or more drinks per week had a 21 percent reduction in total strokes (hemorrhagic or ischemic) and a 23 percent reduction in ischemic strokes. The largest reduction in risk of total stroke occurred in participants who consumed one to four drinks per week. Compared with those who consumed less than one drink per week (assigned a relative risk of 1.00), the relative risk for those who consumed one drink per week was 0.75. In participants who had two to four drinks per week, the relative risk was 0.74. In assessing ischemic stroke separately, the lowest relative risks (0.74) were again found in participants who had from two to four drinks per week. Physicians who consumed these same amounts of alcohol had a slightly higher risk of hemorrhagic stroke; however, the differences were not statistically significant.
The authors conclude that the consumption of light-to-moderate amounts of alcohol (from one to seven drinks per week) is associated with a reduction in the overall risk of stroke, specifically ischemic stroke. They add that the risk reduction is less than that observed with medical interventions (i.e., the treatment of high blood pressure).