Vitamin E and C supplementation and risk of cancer in men: posttrial follow-up in the Physicians' Health Study II randomized trial.

Abstract

BACKGROUND:

Recent posttrial analysis of a completed randomized trial found an increased risk of prostate cancer among healthy men taking high-dose vitamin E supplements. Trials that examined the effect of vitamin C supplements on cancer risk are few.

OBJECTIVE:

We examined whether vitamin E or vitamin C supplementation affects the risk of cancer events during posttrial follow-up of the Physicians' Health Study II.

DESIGN:

Beginning in 1997, a total of 14,641 US male physicians aged ≥50 y were randomly assigned to receive 400 IU of vitamin E every other day, 500 mg of vitamin C daily, or their respective placebos. The vitamin E and vitamin C treatment ended in 2007, and observational follow-up continued through June 2011.

RESULTS:

This study included an additional 356 cases of incident prostate cancer and 771 total cancers that developed during a mean (maximum) of 2.8 (3.8) y of posttrial observation. During an overall mean of 10.3 (13.8) y, there were a total of 1373 incident prostate cancers and 2669 total cancers documented. In comparison with placebo, vitamin E supplementation had no effect on the incidence of prostate cancer (HR: 0.99; 95% CI: 0.89, 1.10) or total cancers (HR: 1.02; 95% CI: 0.95, 1.10). There was also no effect of vitamin C supplementation on total cancers (HR: 1.02; 95% CI: 0.94, 1.10) or incident prostate cancer (HR: 1.03; 95% CI: 0.93, 1.15). Neither vitamin E nor vitamin C supplementation had effects on other site-specific cancers overall. Stratification by known cancer risk factors, history of cancer, other randomized treatment, and follow-up time showed no significant interactions.

CONCLUSION:

In this large-scale randomized trial in men, vitamin E and C supplementation had no immediate or long-term effects on the risk of total cancers, prostate cancer, or other site-specific cancers.

• Authors: Lu Wang, Howard D Sesso, Robert J Glynn, William G Christen, Vadim Bubes, JoAnn E Manson, Julie E Buring, J Michael Gaziano
• Journal: The American journal of clinical nutrition (Am J Clin Nutr) Vol. 100 Issue 3 Pg. 915-23 (Sep 2014) ISSN: 1938-3207 [Electronic] United States
• PMID: 25008853 (Publication Type: Comparative Study, Journal Article, Observational Study, Randomized Controlled Trial, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: © 2014 American Society for Nutrition.

Chemical References

• Antioxidants
• Vitamin E
• Ascorbic Acid

Topics

• Aged
• Antioxidants (adverse effects, therapeutic use)
• Ascorbic Acid (adverse effects, therapeutic use)
• Cohort Studies
• Dietary Supplements (adverse effects)
• Double-Blind Method
• Follow-Up Studies
• Humans
• Incidence
• Male
• Middle Aged
• Neoplasms (chemically induced, epidemiology, prevention & control)
• Physicians
• Prostatic Neoplasms (chemically induced, epidemiology, prevention & control)
• Risk Factors
• United States (epidemiology)
• Vitamin E (adverse effects, therapeutic use)