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 greater than or equal to5 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.