Fish Consumption and Ischemic stroke in Southern Sweden

BACKGROUND The relationship between fish intake and stroke incidence has been inconsistent in previous Swedish studies. Here, we report the risk of stroke and fish intake in a cohort from southern Sweden. FINDINGS Data were obtained from an already available population based case-control study where the cases were defined as incident first-time ischemic stroke patients. Complete data on all relevant variables were obtained for 2722 controls and 2469 cases. The data were analyzed with logistic regression analysis. Stroke risk decreased with fat fish intake ([greater than or equal to] 1/week versus < 1/month) in both men and women; adjusted pooled Odds Ratio (OR) 0.69, 95% Confidence Interval (CI): 0.54-0.89. However, stroke risk for women increased with intake of lean fish; adjusted OR 1.63 (95% CI: 1.17-2.28), whereas there was no association with men's lean fish intake; adjusted OR 0.97(95% CI: 0.73-1.27). Fish intake was self-reported retrospectively, yielding uncertain exposure assessment and potential recall bias. The findings regarding lean fish could be explained by recall bias if an individual's inclination to report lean fish consumption depended on both disease status and sex. The fact that the association between fat fish intake and stroke was similar in men and women does not support such a differential in recall. CONCLUSIONS The results suggest fat fish intake to decrease ischemic stroke risk and lean fish intake to increase women's stroke risk. The inconsistent relationship between fish intake and stroke risk reported in previous studies is further stressed by the results of this study.