Background: Experimental studies suggest that omega-3 fatty acid have favorable effects on blood pressure (BP). However, data on the association of long-term dietary intake of omega-3 fatty acid or fish with risk of hypertension in healthy subjects are sparse. We examined whether fish or omega-3 fatty acid consumption was associated with incident hypertension in the Physicians' Health Study (PHS).
Methods: In a prospective cohort study, we analyzed data on 12 279 PHS participants (mean age: 53.0 ± 8.7 years) free of hypertension at baseline. Fish and omega-3 fatty acid consumption were assessed from a baseline semiquantitative food-frequency questionnaire. Incident hypertension was ascertained via self-reports on annual follow-up questionnaires.
Results: During a mean follow-up of 15.8 years, 6299 men (51.3%) developed hypertension. In a multivariable model controlling for established risk factors for hypertension, fish and omega-3 fatty acid consumption was not significantly associated with incident hypertension. The hazard ratio (95% CI) of hypertension was 1.10 (0.93-1.30) for men who consumed at least five servings per week of fish compared with those who did not consume any fish (P for trend = 0.29). For the highest versus lowest quintile of omega-3 fatty acid intake, the hazard ratio of hypertension was 1.02 (0.94-1.11) (P for trend = 0.34). The associations did not vary by type of fish. There was also no evidence of effect modification by baseline BP, BMI, or history of hypercholesterolemia.
Conclusion: Overall, long-term dietary intake of fish and omega-3 fatty acid was not associated with incident hypertension in a cohort of middle-aged and older US men.