Diet and bladder cancer: A meta-analysis of six dietary variables

In 1996, more than 300,000 new cases of bladder cancer were diagnosed world wide. Besides tobacco smoking, occupation, and other factors, diet may play a role in causation of this illness. The authors performed a meta-analytic al review of epidemiologic studies linking six dietary factors to bladder c ancer. These factors include retinol, beta-carotene, fruits, vegetables, me at, and fat. Increased risks of bladder cancer were associated with diets l ow in fruit intake (relative risk (RR) = 1.40, 95% confidence interval (CI) , 1.08, 1.83), and slightly increased risks were associated with diets low in vegetable intake (RR = 1.16, 95% CI: 1.01, 1.34). Elevated risks were id entified for diets high in fat intake (RR = 1.37, 95% CI: 1.16, 1.62) but n ot for diets high in meat intake (RR = 1.08, 95% CI: 0.82, 1.42). No increa sed risks were found for diets low in retinol (RR = 1.01, 95% CI: 0.83, 1.2 3) or beta-carotene (RR = 1.10, 95% CI: 0.93, 1.30) intake. These results s uggest that a diet high in fruits and vegetables and low in fat intake may help prevent bladder cancer, but the individual dietary constituents that r educe the risks remain unknown.