Dietary folate intake may decrease risk of bladder cancer

Download PDF Copy

May 10 2006

Genetic alterations, epigenetic events and environmental exposures all contribute to the development of bladder cancer.

It is suggested that some factors, such as vitamins can decrease the risk of bladder cancer. Dr. Schabath and colleagues hypothesized that dietary folate, which is involved in DNA methylation may have a chemopreventive effect in the bladder. Their study results appeared in Nutrition and Cancer.

Between 1999 and 2003 bladder cancer cases and controls were accrued from clinics in Houston, Texas. An interview and questionnaire was used to collect dietary data. Dietary folate intake was separated into 3 categories; naturally occurring food folate, dietary folate equivalents (DFE) from food sources and DFE from all sources.

The study cohort consisted of 409 bladder cancer patients and 451 healthy controls. Bladder cancer patients reported a lower intake of folate than controls for food folate and DFE from food sources, but not for DFE from all sources. A bladder cancer risk reduction occurred with each increasing quartile of folate intake, which meant that the highest quartile of folate intake conferred a 54% risk reduction. This was also true for the highest quartile risk reduction for DFE from food sources (59%) and DFE from all sources (35%).

Five major folate food sources were examined and legumes were the only dietary source that yielded a statistically significant protective effect. With regards to smoking, a significant elevated risk effect was noted in active smokers and a borderline significant elevated risk was present in former smokers. Heavy smokers with low folate intake had a 2.31-fold increased risk, compared to heavy smokers with high folate intake who had a reduced odds ratio of 1.21. For light smokers, a high folate intake demonstrated a non-significant protective effect.

These data establish rationale for prospective testing the protective effect of folate on the development of bladder cancer with an emphasis on the smoking patient population.

Reference: