The limited effect of omega-3 polyunsaturated fatty acids on cardiovascular risk in patients with impaired glucose metabolism: a meta-analysis

Abstract

Objectives: The impacts of marine-derived n-3 polyunsaturated fatty acids (n-3 PUFAs) on cardiovascular risk are not well known. We conducted this meta-analysis to determine the effects of n-3 PUFAs on cardiovascular outcomes and cardiovascular risk markers in patients with impaired glucose metabolism (IGM).

Design and methods: We searched PUBMED, EMBASE, The Cochrane Library and reference lists of relevant papers for high quality randomized controlled trials comparing dietary intake of n-3 PUFAs with placebo in IGM patients. Data was extracted and quality assessed independently by two reviewers. Authors were contacted for missing information. Overall estimates were calculated using a random-effects model or a fixed-effects model, and the possibility of publication bias was examined using a funnel plot. Subgroup analyses were conducted to explore the association between the risk markers and study characteristics.

Results: Our meta-analysis included 19 studies, 24,788 patients. Compared with placebo, n-3 PUFAs had no statistically significant reduce effect on cardiovascular mortality, major cardiovascular events, all-cause mortality or composite endpoint of all-cause mortality or hospitalization for cardiovascular cause, however it can significantly reduce the level of triglycerides (weighted mean difference [WMD] -0.25mmol/L; 95% CI -0.37 to -0.13: p<0.001; 12 trials, 13,921 patients).

Conclusion: Marine-derived n-3 polyunsaturated fatty acids have no protective effect on cardiovascular mortality, major cardiovascular events, all-cause mortality and composite endpoint of all-cause mortality or hospitalization for cardiovascular cause in IGM patients, but can reduce triglyceride level.

Keywords: Cardiovascular risk markers; Docosahexaenoic acid; Eicosapentaenoic acid; Impaired glucose metabolism; Omega-3 polyunsaturated fatty acids.