Low Amounts of Alcohol Consumption are Associated with a Reduced Risk of Stroke, While Heavy Drinking May Increase It

Low amounts of alcohol consumption are associated with a reduction in the risk of ischemic stroke, while alcohol use may increase the risk of hemorrhagic stroke. In this meta-analysis—based on 27 prospective studies reporting data on 1,425,513 individuals—the authors used a spline analysis to estimate the average intake reported by subjects; they classified <15 g of alcohol in a day as “light” consumption, 15–30 g in a day as “moderate,” and larger amounts as “heavy.” Data on the patterns of consumption or the types of alcoholic beverages consumed were not available. A spline is a relation defined by a piecewise polynomial function (meaning there can be multiple equations, and they are more complex than simple linear formulas).

• For total stroke, there was a 15% reduction in risk associated with light alcohol consumption (relative risk [RR], 0.85), no effect with moderate, and a 20% increased risk with heavy consumption (RR, 1.20).
• For ischemic stroke and stroke mortality, there were decreases in risk with light alcohol consumption (RR, 0.81 and 0.67, respectively), but no significant effects associated with either moderate or heavy consumption.
• For hemorrhagic stroke, the relative risk for participants reporting heavy alcohol consumption was higher than that of abstainers, but none of the differences were statistically significant.

Comments:

This meta-analysis found a J-shaped association between alcohol consumption and stroke mortality with a decrease in the risk of total stroke among participants who reported consumption of 0–20 g of alcohol in a day, and possibly an increase in the risk among those with heavy consumption.

R. Curtis Ellison, MD

Reference:

Zhang C, Qin YY, Chen Q, et al. Alcohol intake and risk of stroke: a dose-response meta-analysis of prospective studies. Int J Cardiol. 2014;174(3):669–677.