Light to moderate alcohol consumption has been consistently associated with decreased risk of heart disease, but data for stroke are less certain. Some studies have suggested a decreased risk of stroke for light to moderate alcohol intake, with possibly increased risk at higher levels.
73,450 female participants in the Nurses' Health Study who were free of cardiovascular disease and cancer at baseline, were followed from 1984-2006. Data on self reported alcohol consumption were assessed at baseline, and updated in 1988, 1990, and every 4 years thereafter. Ascertainment of stroke, and information on potential confounders were collected at baseline and biennially. Strokes were classified according to the National Survey of Stroke criteria. Time-varying Cox models were used to evaluate the multivariate adjusted association of alcohol consumption over time with incident total stroke and stroke types.
During 1,572,194 person-years of follow-up, 1,822 incident strokes occurred. In multivariate adjusted analyses (Table 1), alcohol consumption was associated with a decreased risk of total stroke across all categories of intake, even for 0-4.9 gm/d. No increased risk was observed in the highest intake category (30 gm/d). The relationship was similar for ischemic stroke, but for hemorrhagic stroke significantly reduced risk was only observed for categories <15 gm/d. No effect modification by hormone therapy, hypertension or aspirin intake was observed. However, we observed possible effect modification by age, with greater reductions in risk with light consumption in younger than older women (p-value interaction=0.04).
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