Age, gender and smoking habits are the most important risk factors for bladder cancer. Selenium supplement, in addition to standard care, does not diminish recurrence in bladder cancer patients compared to placebo and increases the risk of bladder cancer with 6% for each increase of 10 mcg/L of blood selenium level. Each extra daily portion of vegetables decreases the risk of bladder cancer with 6%. Neither diabetes nor metformin was associated with bladder cancer risk in the Clinical Practice Research Datalink.
(BELG J MED ONCOL 2017;11(8):393-395)