- Question
- Does supplementation with marine omega-3 fatty acids prevent cardiovascular events and cancer in a general population without prior disease?
- Design
- Randomized, placebo-controlled trial with a 2x2 factorial design (vitamin D3 and omega-3), conducted in the United States with 25871 participants, including 5106 black participants. Median follow-up was 5.3 years; this article reports the omega-3 versus placebo comparison.
- Population
- Men aged 50 years or older and women aged 55 years or older at usual risk, enrolled for primary prevention of cardiovascular disease and cancer.
- Intervention
- Marine omega-3 fatty acids, 1 g per day (with or without vitamin D3 2000 IU per day depending on the factorial arm).
- Control
- Placebo.
- Primary outcome
- Major cardiovascular events (composite of myocardial infarction, stroke, or death from cardiovascular causes) and invasive cancer of any type.
- Results
- Major cardiovascular events occurred in 386 participants in the omega-3 group and 419 in the placebo group (HR 0.92; 95% CI 0.80 to 1.06; P=0.24). Invasive cancer was diagnosed in 820 and 797 participants, respectively (HR 1.03; 95% CI 0.93 to 1.13; P=0.56). Among secondary endpoints, total myocardial infarction showed an HR of 0.72 (95% CI 0.59 to 0.90).
- Safety
- No excess risks of bleeding or other serious adverse events were observed.
- Conclusion
- Omega-3 supplementation did not lower the incidence of major cardiovascular events or cancer compared with placebo.
- Why it matters
- It provided large-scale evidence against routine omega-3 supplementation for primary cardiovascular and cancer prevention in the general population at usual risk.
Card generated automatically with AI from the abstract of the original publication and the trial registry; every figure was checked against those sources. It may contain errors: verify the data at the source before using it for clinical decisions.
Generated on October 14, 2026