Alcohol, beer, and ischemic stroke

In contrast to the consistent associations of beer and alcohol intake with lower risk of coronary heart disease, their corresponding associations with risk of stroke are more complex and nuanced. In recent cohort studies of alcohol use and ischemic stroke, the association is of modest magnitude, with risk ratios approximating 0.8, and the lowest risk among less-than-daily drinkers. Consumers of 3 or more drinks per day clearly have a higher risk of ischemic stroke, and heavy intake may also acutely trigger strokes. In addition, alcohol use is generally associated with a roughly dose-dependent higher risk of hemorrhagic stroke throughout the full range of intake. These same relationships have generally been seen with both beer and other alcoholic beverages, with only limited evidence that beer intake may not confer as low a risk as wine. The mechanisms that underlie the lower risk of ischemic stroke among moderate drinkers have not yet been definitively explored. The higher risks of hypertension and atrial fibrillation that accompany heavy drinking may explain its association with ischemic stroke, and the antithrombotic effects of alcohol may mediate its link with hemorrhagic stroke.