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JAMA. 2009 Jan 7;301(1):52-62. doi: 10.1001/jama.2008.862. Epub 2008 Dec 9.

Vitamins E and C in the prevention of prostate and total cancer in men: the Physicians' Health Study II randomized controlled trial.

Author information

  • 1Division of Preventive Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02120, USA. jmgaziano@partners.org

Abstract

CONTEXT:

Many individuals take vitamins in the hopes of preventing chronic diseases such as cancer, and vitamins E and C are among the most common individual supplements. A large-scale randomized trial suggested that vitamin E may reduce risk of prostate cancer; however, few trials have been powered to address this relationship. No previous trial in men at usual risk has examined vitamin C alone in the prevention of cancer.

OBJECTIVE:

To evaluate whether long-term vitamin E or C supplementation decreases risk of prostate and total cancer events among men.

DESIGN, SETTING, AND PARTICIPANTS:

The Physicians' Health Study II is a randomized, double-blind, placebo-controlled factorial trial of vitamins E and C that began in 1997 and continued until its scheduled completion on August 31, 2007. A total of 14,641 male physicians in the United States initially aged 50 years or older, including 1307 men with a history of prior cancer at randomization, were enrolled.

INTERVENTION:

Individual supplements of 400 IU of vitamin E every other day and 500 mg of vitamin C daily.

MAIN OUTCOME MEASURES:

Prostate and total cancer.

RESULTS:

During a mean follow-up of 8.0 years, there were 1008 confirmed incident cases of prostate cancer and 1943 total cancers. Compared with placebo, vitamin E had no effect on the incidence of prostate cancer (active and placebo vitamin E groups, 9.1 and 9.5 events per 1000 person-years; hazard ratio [HR], 0.97; 95% confidence interval [CI], 0.85-1.09; P = .58) or total cancer (active and placebo vitamin E groups, 17.8 and 17.3 cases per 1000 person-years; HR, 1.04; 95% CI, 0.95-1.13; P = .41). There was also no significant effect of vitamin C on total cancer (active and placebo vitamin C groups, 17.6 and 17.5 events per 1000 person-years; HR, 1.01; 95% CI, 0.92-1.10; P = .86) or prostate cancer (active and placebo vitamin C groups, 9.4 and 9.2 cases per 1000 person-years; HR, 1.02; 95% CI, 0.90-1.15; P = .80). Neither vitamin E nor vitamin C had a significant effect on colorectal, lung, or other site-specific cancers. Adjustment for adherence and exclusion of the first 4 or 6 years of follow-up did not alter the results. Stratification by various cancer risk factors demonstrated no significant modification of the effect of vitamin E on prostate cancer risk or either agent on total cancer risk.

CONCLUSIONS:

In this large, long-term trial of male physicians, neither vitamin E nor C supplementation reduced the risk of prostate or total cancer. These data provide no support for the use of these supplements for the prevention of cancer in middle-aged and older men.

TRIAL REGISTRATION:

clinicaltrials.gov Identifier: NCT00270647.

Comment in

PMID:
19066368
[PubMed - indexed for MEDLINE]
PMCID:
PMC2774210
Free PMC Article
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