Vitamin Supplements Fail to Have an Impact on Bladder Cancer: Presented at AUA

By Ed Susman
http://www.docguide.com/news/content.nsf/news/852576140048867C852577360056F1A4
SAN FRANCISCO — June 2, 2010 — Vitamin C, vitamin D and/or vitamin E do not provide any significant benefit in preventing the occurrence of bladder cancer, researchers said here at the 2010 American Urological Association (AUA) Annual Meeting.
"We believe that it is very unlikely that supplementation with these vitamins is having any effect on bladder cancer," stated James Hotaling, MD, University of Washington, Seattle, Washington, speaking here on May 30 at a press briefing.
Working with data collected by researchers at the Fred Hutchinson Comprehensive Cancer in Seattle, Dr. Hotaling and colleagues identified 77,050 residents between the ages of 50 and 76 years old who had completed a 24-page questionnaire between 2000 and 2002 and were then followed for the next 5 years through the Surveillance, Epidemiology, and End Results (SEER) cancer registry.
Overall, 330 of the residents were found to have developed urothelial-cell carcinoma of the bladder.
Dr. Hotaling and colleagues stratified the aggregate vitamin use over the previous 10 years into none and tertiles of 10-year average intake per day. The patients in the top tertiles were taking daily doses of the following: 322 to 1,600 mcg of vitamin C; 10 to 30 mcg of vitamin D, or 215 to 1,000 mcg of vitamin E.
In a multivariate analysis, the risk of bladder cancer by tertiles was examined, and the researchers found that vitamin use provided no protective effect on urothelial-cell carcinoma. They observed a nonsignificant 8% reduction in risk of bladder cancer between the top tertile of patients taking vitamin C compared with patients not taking any supplemental vitamin C. They also observed a nonsignificant 4% reduction in risk between the top tertile of vitamin D users compared with non-supplement users and a nonsignificant 3% reduction between the top tertile of vitamin E users and non-supplement users.
Hazard ratios (HR) were estimated by multivariate Cox regression models controlling for age, gender, race, body mass index (BMI), fruit and vegetable intake, and smoking status. About 52% of the individuals participating in this study were women, and more than 90% of the group was white. Approximately 78% of the cases of bladder cancer occurred in men.
"It's really disturbing to think that so many people are taking vitamins, assuming that these pills are providing some sort of health benefits," said session moderator Mark A. Moyad, MD, University of Michigan Medical Center, Ann Arbor, Michigan. "The reality is that very little scientific research has proven vitamins to be effective in protecting against cancer, and some studies have even shown that taking certain vitamins could increase one's risk of cancer."
Dr. Moyad added that it was somewhat comforting that this study did not indicate that taking the vitamins caused harm — aside from the cost of the supplements.
The greatest risk factor for bladder cancer, the data revealed, was smoking — with current smokers having a risk 4 times greater than those who never smoked.
Funding for this study was provided by the National Institutes of Health.
Presentation title: Long-Term Use of Supplemental Vitamin C, Vitamin D and Vitamin E Does Not Reduce the Risk of Urothelial Cell Carcinoma of the Bladder in the Vitamins and Lifestyle Study. Abstract 1162