Association between exposure to environmental heavy metals and gastrointestinal and urinary cancer mortality.

Environmental exposure to heavy metals has been associated with cancer. Nonetheless, the effects of exposure to combined heavy metals on cancer mortality of urinary and gastrointestinal systems have not been examined. This study assessed the long-term association between environmental exposure to multiple heavy metals and cancer mortality rates in the digestive and urinary tracts. The death rates/100,000 inhabitants over 41 years were collected from Santo Amaro, the exposed town with a former lead smelter, and Ribeira do Pombal, the reference town, in Bahia, Brazil. The exposure duration, age and gender were considered predictors. The overall accuracy of the models ranged from 84 to 97%. For the population above 80 years, the probability of total mortality went from 20% in the first 6 years of exposure to over 70% after 20 years. The same trend was observed for the urinary system. For the digestive system, the mortality in the elders started after 15 years of exposure and peaked with a 30% probability after 35 years. In conclusion, environmental exposure to multiple heavy metals was linked to cancer-related deaths in the gastrointestinal and urinary tracts of the elderly population.