Erythrocyte long-chain omega-3 fatty acid levels are inversely associated with mortality and with incident cardiovascular disease: The Framingham Heart Study

J Clin Lipidol. May-Jun 2018;12(3):718-727.e6. doi: 10.1016/j.jacl.2018.02.010. Epub 2018 Mar 2.

Abstract

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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Cardiovascular Diseases / blood*
  • Cardiovascular Diseases / epidemiology
  • Cardiovascular Diseases / mortality*
  • Cholesterol / blood
  • Cohort Studies
  • Erythrocytes / metabolism*
  • Fatty Acids, Omega-3 / blood*
  • Female
  • Humans
  • Incidence
  • Longitudinal Studies*
  • Male
  • Middle Aged

Substances

  • Fatty Acids, Omega-3
  • Cholesterol