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.