AACR: Multivitamins Reduce Non-Prostate Cancer Risks Among Men Over Age 50
The study was published October 17 in JAMA, the Journal of the American Medical Association.
“In this large-scale, randomized, placebo-controlled trial among middle-aged and older men, long-term daily multivitamin use had a modest but statistically significant reduction in the primary end point of total cancer after more than a decade of treatment and follow-up,” reported lead authors J. Michael Gaziano, MD, MPH, and Howard D. Sesso, ScD, PhD, of Brigham and Women's Hospital and Harvard Medical School in Boston, Massachusetts.
During a median follow-up period of 11.2 years, 2,669 study participants were diagnosed with confirmed cancers, including 1,373 cases of prostate cancer. Multivitamin use was associated with a significantly lower incidence of total cancer compared to placebo (17.0 vs 18.3 diagnoses per 1,000 person-years; HR, 0.92; 95% CI, 0.86-0.998; P=0.04).
The results were more modest than the cancer-prevention benefits associated with not smoking tobacco, exercise, and a healthy diet.
There was no significant effect of daily multivitamin intake on prostate cancer (P=0.76) or other site-specific cancers. Total mortality was not reduced (P=0.13).
Among 1,312 study participants with a history of prior cancer diagnoses, total cancer incidence was significantly reduced among those assigned to the multivitamin arm of the study (HR, 0.73; 95% CI, 0.56-0.96; P=0.02). The effect “appeared stronger” among men with a history of prior cancers than men without previous cancer histories at baseline, but was not significantly greater than that observed among men without prior cancers (HR, 0.94; 95% CI, 0.87-1.02; P=.15), the authors reported.
However, “the effect of a daily multivitamin on total epithelial cancer was stronger among men with a history of cancer at baseline,” the authors noted (HR, 0.66; 95% CI, 0.50-0.88; P=0.004).
Men taking multivitamins were more likely than placebo-arm patients to have rashes (HR, 1.07; 95% CI, 1.01-1.14; P=0.03) and nose bleeds (HR, 1.10; 95% CI, 1.02-1.18; P=0.01), but were less likely to experience minor hematuria (HR, 0.91; 95% CI, 0.84-0.98; P=0.02).
“There was significant effect modification by parental history of cancer,” the authors noted. Men without parental histories of cancer benefited from multivitamin use (HR, 0.86, 95% CI, 0.76-0.98; P=0.02), they wrote, while men with parental histories of cancer did not (P=.37).
“There have been several (previous) large observational studies of long-term multivitamin use on the risk of total cancer and other site-specific cancers,” Dr. Sesso said. “The difference is that these are not clinical trials, and do not account for confounding.”