Cardiovascular disease remains the commonest health problem in developed countries, and residual risk after implementing all current therapies is still high. The use of marine omega-3 fatty acids (DHA and EPA) has been recommended to reduce cardiovascular risk by multiple mechanisms. To update the current evidence on the influence of omega-3 on the rate of cardiovascular events. We used the MEDLINE and EMBASE databases to identify clinical trials and randomized controlled trials of omega-3 fatty acids (with quantified quantities) either in capsules or in dietary intake, compared to placebo or usual diet, equal to or longer than 6 months, and written in English. The primary outcome was a cardiovascular event of any kind and secondary outcomes were all-cause mortality, cardiac death and coronary events. We used RevMan 5·1 (Mantel-Haenszel method). Heterogeneity was assessed by the I2 and Chi2 tests. We included 21 of the 452 pre-selected studies. We found an overall decrease of risk of suffering a cardiovascular event of any kind of 10 % (OR 0·90; [0·85-0·96], p = 0·001), a 9 % decrease of risk of cardiac death (OR 0·91; [0·83-0·99]; p = 0·03), a decrease of coronary events (fatal and non-fatal) of 18 % (OR 0·82; [0·75-0·90]; p < 1 × 10⁻⁴), and a trend to lower total mortality (5 % reduction of risk; OR 0·95; [0·89-1·02]; p = 0·15. Most of the studies analyzed included persons with high cardiovascular risk. marine omega-3 fatty acids are effective in preventing cardiovascular events, cardiac death and coronary events, especially in persons with high cardiovascular risk.
