Dietary fish intake and incident atrial fibrillation (from the Women's Health Initiative).

Experimental and clinical trial data have suggested an association between fish oil intake and atrial fibrillation (AF). However, previous observational studies have reported conflicting results regarding this association. Thus, we sought to compare the association between dietary fish intake and incident AF in a large sample of older, postmenopausal women. We included 44,720 participants from the Women's Health Initiative clinical trials who were not enrolled in the dietary modification intervention arm and without AF at baseline. The dietary intake of nonfried fish and omega-3 fatty acid intake was estimated from a Food Frequency Questionnaire at study entry. Incident AF was determined by follow-up electrocardiography at years 3 and 6. The baseline characteristics and rates of incident AF were compared across the quartiles of fish intake. Adjusted logistic regression models were used to evaluate the association between dietary nonfried fish intake and incident AF. A total of 378 incident cases of AF occurred during the follow-up period. In the age-adjusted models, no association was found between dietary nonfried fish intake and incident AF (odds ratio 1.17, 95% confidence interval 0.88 to 1.57 for quartile 4 vs quartile 1 of dietary fish intake). Similar findings were observed in the multivariate models and in the subgroup analyses. In conclusion, in a large cohort of healthy women, we found no evidence of an association between fish or omega-3 fatty acid intake and incident AF.