Omega-3 Fatty Acids as Potential Predictors of Sudden Cardiac Death and Cardiovascular Mortality: A Systematic Review and Meta-Analysis

Background/Objectives: Sudden cardiac death (SCD) poses a significant burden on the modern-day public health system; however, while our understanding of the underlying pathophysiology is still evolving and may not be complete, many insights are known and applied every day. Targeted prevention methods are continually being developed and refined. We conducted a systemic review and meta-analysis to identify a blood nutritional biomarker that can predict and screen population groups at high risk for cardiovascular disease mortality (CVD mortality) or SCD. Methods: The literature search was conducted from November 2023 to 31 January 2024. Based on previous literature research, we studied the association between omega-3 fatty acids (n-3 FA; eicosapentaenoic acid [EPA], docosapentaenoic acid [DPA] and docosahexaenoic acid [DHA]) and SCD and/or CVD mortality individually and in combination. We evaluated and selected 10 prospective cohort studies out of 1789 related publications, with an average follow-up period of 8.7 years. A multivariate adjusted hazard ratio (HR) with 95% confidence interval (CI) was calculated and sub-analyzed to obtain a general trend of reduced risk of SCD in a high n-3 FA intake group from the general population. Results: Finally, we included 10 articles with a total sample size of 310,955 participants. We found an inverse association between circulating n-3 FA levels and SCD. The summary HR of SCD and CVD mortality for high versus low circulating n-3 FA levels (EPA + DHA + DPA) in serum plasma phospholipid was 0.55 (95% CI: 0.37-0.82) and that of EPA + DHA in RBC was 0.67 (95% CI: 0.45-0.99). Based on the sub-analysis, the HR of EPA (%) was 0.79 (95% CI: 0.60-0.82) and that of DHA (%) was 0.72 (95% CI: 0.60-0.87). Conclusions: Our results suggest a potential cardio-protective association between high EPA and DHA levels in blood and a reduced incidence of adverse cardiac events.