Fish consumption and incidence of stroke: a meta-analysis of cohort studies.

BACKGROUND AND PURPOSE Results from observational studies on fish consumption and risk of stroke are inconsistent. We quantitatively assessed the relationship between fish intake and incidence of stroke using a meta-analysis of cohort studies. METHODS We searched the Medline and Embase databases (1966 through October 2003) and identified 9 independent cohorts (from 8 studies) that provided a relative risk (RR) and corresponding 95% CI for total or any type of stroke in relation to fish consumption. Pooled RR and 95% CI of stroke were estimated by variance-based meta-analysis. RESULTS Compared with those who never consumed fish or ate fish less than once per month, the pooled RRs for total stroke were 0.91 (95% CI, 0.79 to 1.06) for individuals with fish intake 1 to 3 times per month, 0.87 (95% CI, 0.77 to 0.98) for once per week, 0.82 (95% CI, 0.72 to 0.94) for 2 to 4 times per week, and 0.69 (95% CI, 0.54 to 0.88) for > or =5 times per week (P for trend=0.06). In stratified analyses of 3 large cohort studies with data on stroke subtypes, the pooled RRs across 5 categories of fish intake were 1.0, 0.69 (95% CI, 0.48 to 0.99), 0.68 (95% CI, 0.52 to 0.88), 0.66 (95% CI, 0.51 to 0.87), and 0.65 (95% CI, 0.46 to 0.93) for ischemic stroke (P for trend=0.24); and 1.0, 1.47 (95% CI, 0.81 to 2.69), 1.21 (95% CI, 0.78 to 1.85), 0.89 (95% CI, 0.56 to 1.40), and 0.80 (95% CI, 0.44 to 1.47) for hemorrhagic stroke (P for trend=0.31). CONCLUSIONS These results suggest that intake of fish is inversely related to risk of stroke, particularly ischemic stroke. Fish consumption as seldom as 1 to 3 times per month may protect against the incidence of ischemic stroke.