Stroke is the leading cause of morbidity and mortality in many countries, 600,000 falling victim in the US alone in 1998. Past studies in North America and Europe have found a J or U shaped curve, suggesting that moderate consumption of alcohol protects against ischemic stroke.Klaus Berger et al of Brigham and Womens Hospital (a Harvard University affiliate) have published an enlightening study on light to moderate drinking and the overall risk of stroke, in the New England Journal of Medicine vol 341, no. 21 November 99.

The report studied 22,000 male physicians between the ages of 40 and 84, who were participating in the Physicians Health Study and drank between 0 and 7 drinks per week. At base line the participants, who were followed up for 12 years, reported that they had no history of stroke, transient ischemic attack or myocardial infarcation and were free of cancer.

During the 12 year follow up, 679 strokes (557 ischemic, 88 hemorrhagic strokes, plus 34 of unknown type) were reported.

When compared with non-drinkers, consumers of one or more drink a week had a reduced risk, not only of ischemic stroke (23%) but of overall risk of stroke (21%). No association was found between moderate alcohol consumption and hemorrhagic stroke, contrary to reports by some papers. Interestingly, blood pressure was lowest amongst participants who had one to four drinks per week and obesity lessened with increasing alcohol intake.

The authors noted that their cohort was of healthy males of high socio-economic and educational status, whose risk of stroke would differ substantially from that of men in the general US population.

However, the size of the cohort study, the long and detailed follow up and the allowances for cofounders combine to produce convincing evidence that light to moderate alcohol consumption (1 - 7 14g units a week) reduces the risk of overall stroke by 20% or more.