Fish, long chain omega-3 polyunsaturated fatty acids consumption, and risk of all-cause mortality: a systematic review and dose-response meta-analysis from 23 independent prospective cohort studies.

BACKGROUND AND OBJECTIVES The consumption of fish and long chain omega-3 polyunsaturated fatty acids (n-3 PUFA) may influence the risk of all-cause mortality, but the findings have been inconsistent. The current systematic review and meta-analysis is to clarify the association between fish and long chain n-3 PUFA consumption with risk of all-cause mortality. METHODS AND STUDY DESIGN Studies published before March 2017 were identified through electronic searches using PubMed, Scopus and Web of Science database. We included prospective cohort studies that reported relative risks with 95% CI of all-cause mortality for fish and long chain n-3 PUFA consumption. Results were combined using a random effects model. RESULTS Twenty-three prospective cohorts with a total of 1,035,416 participants were included. Twenty-two pooled studies involving 985,126 participants indicated that fish intake was associated with 6% (RR: 0.94; 95% CI: 0.90, 0.98) reduction in risk of all-cause mortality. Six studies with 430,579 participants investigated the association between long chain n-3 PUFA and all-cause mortality risk, the relative risk for highest versus lowest category was 0.86 (95% CI: 0.80, 0.93). Doseresponse analysis suggested that the risk of all-cause mortality was reduced by 7% (RR: 0.93; 95% CI: 0.88, 0.99) for every 0.2 g per day increment in long chain n-3 PUFA consumption. CONCLUSIONS Current meta-analysis indicates that both fish and long chain n-3 PUFA consumption are inversely associated with risk of all-cause mortality. These findings could have public health implications with regard to lowering risk of all-cause mortality through dietary interventions.