Intake of fish and omega-3 fatty acids and risk of stroke in women

Context Some prospective studies have shown an inverse association between fish intake and risk of stroke, but none has examined the relationship of f ish and omega-3 polyunsaturated fatty acid intake with risk of specific str oke subtypes. Objective To examine the association between fish and omega-3 polyunsaturat ed fatty acid intake and risk of stroke subtypes in women. Design, Setting, and Subjects Prospective cohort study of women in the Nurs es' Health Study cohort, aged 34 to 59 years in 1980, who were free from pr ior diagnosed cardiovascular disease, cancer, and history of diabetes and h ypercholesterolemia and who completed a food frequency questionnaire includ ing consumption of fish and other frequently eaten foods. The 79839 women w ho met our eligibility criteria were followed up for 14 years. Main Outcome Measure Relative risk of stroke in 1980-1994 compared by categ ory of fish intake and quintile of omega-3 polyunsaturated fatty acid intak e. Results After 1 086 261 person-years of follow-up, 574 incident strokes wer e documented, including 119 subarachnoid hemorrhages, 62 intraparenchymal h emorrhages, 303 ischemic strokes (264 thrombotic and 39 embolic infarctions ), and 90 strokes of undetermined type. Among thrombotic infarctions, 90 la rge-artery occlusive infarctions and 142 lacunar infarctions were identifie d. Compared with women who ate fish less than once per month, those with hi gher intake of fish had a lower risk of total stroke: the multivariate rela tive risks (RRs), adjusted for age, smoking, and other cardiovascular risk factors, were 0.93 (95% confidence interval [CI], 0.65-1.34) for fish consu mption 1 to 3 times per month, 0.78 (95% CI, 0.55-1.12) for once per week, 0.73 (95% CI, 0.47-1.14) for 2 to 4 times per week, and 0.48 (95% CI, 0.21- 1.06) for 5 or more times per week (P for trend = .06). Among stroke subtyp es, a significantly reduced risk of thrombotic infarction was found among w omen who ate fish 2 or more times per week (multivariate RR, 0.49; 95% CI, 0.26-0.93). Women in the highest quintile of intake of long-chain omega-3 p olyunsaturated fatty acids had reduced risk of total stroke and thrombotic infarction, with multivariate RRs of 0.72 (95 % CI, 0.53-0.99) and 0.67 (95 % CI, 0.42-1.07), respectively. When stratified by aspirin use, fish and om ega-3 polyunsaturated fatty acid intakes were inversely associated with ris k of thrombotic infarction, primarily among women who did not regularly tak e aspirin. There was no association between fish or omega-3 polyunsaturated fatty acid intake and risk of hemorrhagic stroke. Conclusions Our data indicate that higher consumption of fish and omega-3 p olyunsaturated fatty acids is associated with a reduced risk of thrombotic infarction, primarily among women who do not take aspirin regularly, but is not related to risk of hemorrhagic stroke.