Background: The extent to which omega-3 fatty acid status is related to risk for death from any cause and for incident cardiovascular disease (CVD) remains controversial.
Objective: To examine these associations in the Framingham Heart Study.
Design: Prospective and observational.
Setting: Framingham Heart Study Offspring cohort.
Measurements: The exposure marker was red blood cell levels of eicosapentaenoic and docosahexaenoic acids (the Omega-3 Index) measured at baseline. Outcomes included mortality (total, CVD, cancer, and other) and total CVD events in participants free of CVD at baseline. Follow-up was for a median of 7.3 years. Cox proportional hazards models were adjusted for 18 variables (demographic, clinical status, therapeutic, and CVD risk factors).
Results: Among the 2500 participants (mean age 66 years, 54% women), there were 350 deaths (58 from CVD, 146 from cancer, 128 from other known causes, and 18 from unknown causes). There were 245 CVD events. In multivariable-adjusted analyses, a higher Omega-3 Index was associated with significantly lower risks (P-values for trends across quintiles) for total mortality (P = .02), for non-CVD and non-cancer mortality (P = .009), and for total CVD events (P = .008). Those in the highest (>6.8%) compared to those in the lowest Omega-3 Index quintiles (<4.2%) had a 34% lower risk for death from any cause and 39% lower risk for incident CVD. These associations were generally stronger for docosahexaenoic acid than for eicosapentaenoic acid. When total cholesterol was compared with the Omega-3 Index in the same models, the latter was significantly related with these outcomes, but the former was not.
Limitations: Relatively short follow-up time and one-time exposure assessment.
Conclusions: A higher Omega-3 Index was associated with reduced risk of both CVD and all-cause mortality.
Keywords: Docosahexaenoic acid; Eicosapentaenoic acid; Epidemiology; Omega-3 fatty acids; Prospective cohort study.
Copyright © 2018 National Lipid Association. Published by Elsevier Inc. All rights reserved.