Daily multivitamins to reduce mortality, cardiovascular disease, and cancer.

Evidence • Meta-analysis1 of 21 RCTs, with 91 074 patients (54% men) randomized to multivitamins or placebo for 3.5 years. -No effect on overall mortality, relative risk (RR) = 0.98 (95% CI 0.94 to 1.02); cancer mortality, RR = 0.96 (95% CI 0.88 to 1.04); or CVD mortality, RR = 1.01 (95% CI 0.93 to 1.09). -Multiple subgroup testing found no differences. -No evidence of publication bias or meaningful heterogeneity. • Heavily publicized RCT2,3 of 14 641 men (mean age 64.3 years) randomized to multivitamin or placebo, followed for 11.2 years. -No effect on overall mortality, hazard ratio (HR) = 0.94 (95% CI 0.88 to 1.02); cancer mortality, HR = 0.88 (95% CI 0.77 to 1.01); CVD mortality, HR = 0.95 (95% CI 0.83 to 1.09); or CVD events, HR = 1.01 (95% CI 0.91 to 1.10). -Reduced cancer incidence, HR = 0.92 (95% CI 0.86 to 0.998). —These HRs were adjusted (for unclear reasons). —Unadjusted HR for cancer incidence was not significant, RR = 0.94 (95% CI 0.87 to 1.003). -Issues: lots of exclusion (eg, removing noncompliant patients), adjustments always in favour of multivitamins.