Alcohol, ischaemic and haemorrhagic stroke

Message

This cohort study found that light to moderate drinking, between one and seven drinks a week, reduced the risk of ischaemic stroke by 23% in men. It did not examine the effects of consuming two or more drinks a day. There was no association between alcohol consumption and hemorrhagic stroke.

Reference

K Berger et al. Light to moderate alcohol consumption and the risk of stroke among U.S. male physicians. The New England Journal of Medicine 1999 341: 1557-1564.

Study

In 1982, 21,870 male physicians, from the US Physicians' Health Study, aged 40-84 years, completed questionnaires on their medical history and lifestyle. Medical history was updated annually. Frequency of alcohol consumption was reassessed after seven years. At the beginning of the study, participants did not have a history of stroke, transient ischaemic attack or myocardial infarction. They were followed for an average of 12 years, during which time 679 strokes were reported (557 ischaemic, 88 hemorrhagic, 34 unknown). Strokes were classified as ischaemic or hemorrhagic by a neurologist on the basis of medical records and brain imaging.

Results

Men consuming at least one drink a week reduced the risk of ischaemic stroke by 23% compared with men having less than one drink a week, after adjusting for age, systolic blood pressure, smoking, body mass index, exercise, diabetes and hypertension (relative risk 0.77, 95% confidence interval 0.63 to 0.94).

No association was found between alcohol consumption and hemorrhagic stroke.

Comment

As 97% of participants reported consuming between one and seven drinks a week, this study investigated the effects of light to moderate alcohol consumption on stroke. It did not examine the small number of participants having two or more drinks a day.

Only the frequency of alcohol consumption was assessed; participants may have consumed more than one drink at a time. However, as the beneficial level is a range of consumption (one to seven drinks a week) and not a single category, any change is likely to be small and the level would remain within a moderate level of consumption.