Association between levels of urinary heavy metals and increased risk of urothelial carcinoma

Objectives: To evaluate possible sources of exposure to heavy metals in the general population, and to determine the association between urinary heavy metals and urothelial carcinoma risk. Methods: We recruited 205 patients with urothelial carcinoma and 406 control participants for a case-control study between June 2011 and December 2013. The control participants were frequency-matched with cases according to sex and age. We measured the urinary levels of arsenic, cadmium, chromium, nickel and lead by using inductively coupled plasma mass spectrometry. We collected environmental exposure-related information through questionnaires. Multivariate logistic regression and 95% confidence intervals were applied to estimate the urothelial carcinoma risk and potential effects of urothelial carcinoma-related risk factors on the levels of urinary heavy metals. Results: Patients with urothelial carcinoma showed higher urinary levels of arsenic, cadmium, chromium, nickel and lead than the controls. After considering other potential risk factors, a significantly increased risk for urothelial carcinoma was observed in patients with increased urinary levels of cadmium, chromium, nickel and lead. Smokers showed a high urinary cadmium level. In addition to cadmium, a high urinary lead level was associated with cumulative cigarette smoking and herbal medicine use. Conclusion: Environmental factors might contribute to higher urinary levels of heavy metals and ultimately result in urothelial carcinoma carcinogenesis. These findings can promote proper environmental surveillance of exposure to heavy metals in the general population. ? 2016 The Japanese Urological Association.