Relations between the Consumption of Fatty or Lean Fish and Risk of Cardiovascular Disease and All-Cause Mortality: A Systematic Review and Meta-Analysis

Fish consumption is associated with a reduced risk of cardiovascular diseases (CVDs) partly ascribed to the high content of long-chain (LC) n-3 PUFAs; however, not all fish types are equally rich in these components. To date, it is not clear whether the beneficial effects of fish consumption are shared by fatty and lean fish. Therefore, the aim of this meta-analysis was to synthesize knowledge regarding the relation between the intake of fatty fish or lean fish and the risk of cardiovascular events and all-cause mortality. We conducted a systematic search in PubMed, Web of Science, and Embase until May 2021 for full text with a prospective design involving humans providing data for the highest compared with the lowest fish consumption categories. Summary risk ratios (RRs) and 95% CIs were estimated using a random-effects model. Out of 1902 articles retrieved from the literature search, 19 reports met the criteria for inclusion in the meta-analysis. Altogether, studies on fatty fish comprised 1,320,596 person-years of follow-up, 20,531 incident coronary heart disease (CHD) cases, 9256 incident CVD cases, and 104,763 total deaths. Studies on lean fish comprised 937,362 person-years of follow-up, 21,636 incident CHD cases, 7315 incident CVD cases, and 16,831 total deaths. An inverse association was present for fatty fish with CHD incidence (RR: 0.92; 95% CI: 0.86, 0.97), CHD mortality (RR: 0.83; 95% CI: 0.70, 0.98), and total mortality (RR: 0.97; 95% CI: 0.94, 0.99). This was not the case for lean fish. The summary estimates for CVD incidence and mortality did not show significant association with both fatty fish and lean fish consumption. The study findings are innovative in highlighting that the health benefits so far linked to fish consumption are, in fact, driven by fatty fish.