Multivitamins in the Prevention of Cancer in Men: The Physicians' Health Study II Randomized Controlled Trial

Gaziano JM, Sesso HD, Christen WG, Bubes V, Smith JP, MacFadyen J, Schvartz M, Manson JE, Glynn RJ, Buring JE

Published in JAMA

Abstract

A large randomized trial following 14,641 male physicians for 11 years to assess the effects of daily multivitamin supplementation on cancer incidence.

Methodology

Large-scale randomized, double-blind, placebo-controlled 2x2 factorial trial of a daily multivitamin with long-term follow-up.

Key Findings

Among 14,641 male physicians aged 50+ followed for a median 11.2 years, a daily multivitamin modestly reduced total cancer incidence (HR 0.92) — roughly 8 fewer cancers per 1,000 person-years of follow-up. There was no significant reduction in prostate cancer, other site-specific cancers, or cancer mortality.

Conclusions

A daily multivitamin produced a small reduction in total cancer incidence in older male physicians, with no effect on cancer death; the absolute benefit is modest and may not generalize beyond this well-nourished population.

Limitations

Participants were almost all well-nourished male physicians with healthy baseline behaviours, limiting generalizability to women, poorer-nourished groups and other ethnicities; the effect on the primary endpoint was small and site-specific analyses were null.