BACKGROUND: The benefit of n-3 polyunsaturated fatty acids (PUFA) supplementation for mortality and cardiovascular events after myocardial infarction is well documented, but the effect of n-3 PUFA in Caucasians without established cardiovascular disease is not known. Our aim was to examine the influence of supplementation with eicosapentaenoic acid and docosahexaenoic acid on all-cause mortality and cardiovascular events in elderly men at high-risk of cardiovascular disease.

DESIGN: In the Diet and Omega-3 Intervention Trial, 563 Norwegian men, 64-76-year old and 72% without overt cardiovascular disease, were randomized to a 3-year 2x2 factorial designed clinical trial of diet counseling and/or 2.4 g n-3 PUFA supplementation. The n-3 PUFA arm was placebo-controlled (corn oil).

METHODS: Demographic parameters and classical risk factors were obtained at baseline. Deaths and cardiovascular events were recorded through 3 years, and the effects of n-3 PUFA-intervention on these outcomes were evaluated in pooled groups of the n-3 PUFA-arm.

RESULTS: There were 38 deaths and 68 cardiovascular events. The unadjusted hazard ratios of all-cause mortality and cardiovascular events were 0.57 (95% confidence interval: 0.29-1.10) and 0.86 (0.57-1.38), respectively. Adjusted for baseline age, current smoking, hypertension, body mass index and serum glucose, hazard ratios were 0.53 (0.27-1.04, P=0.063) and 0.89 (0.55-1.45, P=0.641), respectively.

CONCLUSION: We observed a tendency toward reduction in all-cause mortality in the n-3 PUFA groups that, despite a low number of participants, reached borderline statistical significance. The magnitude of risk-reduction suggests that a larger trial should be considered in similar populations.