A study of male physicians 50 years of age and older found modest but significant reduction in cancer rates associated with daily multivitamin use.
Daily multivitamin use produced significant, although modest, reduction in cancer among men over more than a decade of follow-up, according to the results of a trial
published online on October 17, 2012, in the Journal of the American Medical Association
The researchers conducted a large-scale, randomized, double-blind, placebo-controlled trial of 14,641 male US physicians aged 50 years and older who were enrolled beginning in 1997 with treatment and follow-up through June 1, 2011. The participants had a mean age of 64.3 years and included 1312 men with a history of cancer at randomization. Participants were randomized to take either a daily multivitamin (Centrum Silver) or placebo.
The results showed that during a median follow-up of 11.2 years, there were 2669 participants with confirmed cancer, including 1373 cases of prostate cancer and 210 cases of colorectal cancer. In addition, 2757 (18.8%) of participants died during follow-up, including 859 (5.9%) due to cancer.
Compared with those in the placebo group, those in the multivitamin group had a statistically significant reduction in incidence of total cancer (17.0 events per 1000 person-years compared with 18.3 events per 1000 person-years, respectively, for a hazard ratio of 0.92). There was, however, no significant difference between the multivitamin and placebo groups in terms of risk of developing prostate cancer, colorectal cancer, or other site-specific cancers.
The researchers note that the total cancer rates in the trial were most likely elevated by increased surveillance for prostate-specific antigen and subsequent diagnoses of prostate cancer during the trial follow-up. Approximately half of all confirmed cancers in the trial were prostate cancer, and most of these were early state, lower-grade cases with higher survival rates. Among those in the multivitamin group, there was a significant reduction in total cancer excluding prostate cancer (hazard ratio of 0.88), suggesting that multivitamin use might have an increased effect on more clinically relevant cancer diagnoses.
The trial also found no significant difference in the risk of cancer mortality or total mortality between the multivitamin and placebo groups. However, multivitamin use was associated with a significant reduction in total cancer among the 1312 participants with a baseline history of cancer (hazard ratio of 0.73), indicating that daily multivitamins may have a stronger effect on cancer reduction for secondary prevention.