Gaziano JM et al., JAMA 2012 (Physicians' Health Study II, multivitamins and cancer)

PMID 23162860

Randomized, placebo-controlled factorial trial: 14,641 US male physicians aged 50 and older, daily multivitamin versus placebo, median follow-up 11.2 years. Total cancer HR 0.92 (95% CI 0.86–0.998); no significant effect on cancer mortality.