Consumption of fish and fish oils was first associated with decreased risk of cardiovascular disease almost 50 years ago. Since then, a number of epidemiologic studies have evaluated whether their consumption is specifically associated with stroke. Ecologic/cross-sectional and case-control studies have generally shown an inverse association between consumption of fish and fish oils and stroke risk. Results from five prospective studies have been less consistent, with one showing no association, one showing a possible inverse association, and three demonstrating a significant inverse association. In the latest and largest of these, the Nurses Health Study, the relative risk of total stroke was lower, although not significantly so, among women who regularly ate fish than among those who did not. A significant decrease in the risk of thrombotic stroke (relative risk, 0.49; 95% confidence interval, 0.26-0.93) was observed among women who ate fish at least two times per week compared with women who ate fish less than once per month, after adjustment for age, smoking, and other cardiovascular risk factors; a nonsignificant decrease was observed among women in the highest quintile of long-chain omega-3 polyunsaturated fatty acid intake. No association was observed between consumption of fish or fish oil and hemorrhagic stroke. These data support the hypothesis that consumption of fish several times per week reduces the risk of thrombotic stroke but does not increase the risk of hemorrhagic stroke.
Copyright 2003 CHF, Inc.