B Vitamin and/or {omega}-3 Fatty Acid Supplementation and Cancer: Ancillary Findings From the Supplementation With Folate, Vitamins B6 and B12, and/or Omega-3 Fatty Acids (SU.FOL.OM3) Randomized Trial
Mené sur 2 501 participants âgés de 45 à 80 ans, cet essai randomisé évalue l'effet d'une supplémentation en vitamines B et/ou en acides gras oméga-3 durant 5 ans sur l'incidence du cancer
Background To advance knowledge about the cancer-chemopreventive potential of individual nutrients, we investigated the effects of B vitamin and/or {omega}-3 fatty acid supplements on cancer outcomes among survivors of cardiovascular disease. Methods This was an ancillary study of the Supplementation With Folate, Vitamins B6 and B12 and/or Omega-3 Fatty Acids (SU.FOL.OM3) secondary prevention trial (2003-2009). In all, 2501 individuals aged 45 to 80 years were randomized in a 2 x 2 factorial design to one of the following 4 daily supplementation groups: (1) 5-methyltetrahydrofolate (0.56 mg), pyridoxine hydrochloride (vitamin B6; 3 mg) and cyanocobalamin (vitamin B12; 0.02 mg); (2) eicosapentaenoic and docosahexaenoic acid (600 mg) in a 2:1 ratio; (3) B vitamins and {omega}-3 fatty acids; or (4) placebo. Overall and sex-specific hazard ratios (HRs) and 95% CIs regarding the cancer outcomes were estimated with Cox proportional hazards models. Results After 5 years of supplementation, incident cancer was validated in 7.0% of the sample (145 events in men and 29 in women), and death from cancer occurred in 2.3% of the sample. There was no association between cancer outcomes and supplementation with B vitamins (HR, 1.15 [95% CI, 0.85-1.55]) and/or {omega}-3 fatty acids (HR, 1.17 [95% CI, 0.87-1.58]). There was a statistically significant interaction of treatment by sex, with no effect of treatment on cancer risk among men and increased cancer risk among women for {omega}-3 fatty acid supplementation (HR, 3.02 [95% CI, 1.33-6.89]). Conclusion We found no beneficial effects of supplementation with relatively low doses of B vitamins and/or {omega}-3 fatty acids on cancer outcomes in individuals with prior cardiovascular disease. Trial Registration isrctn.org Identifier: ISRCTN41926726
http://archinte.ama-assn.org/cgi/content/abstract/archinternmed.2011.1450v1