Prospective study of the association of drinking water contaminant exposures with risk of uterine cancer

Some drinking water contaminants, including disinfection byproducts, are known or suspected carcinogens with endocrine-disrupting properties. Analysis among participants of the prospective California Teachers Study investigated associations between some contaminants in drinking water and the risk of uterine cancer. The study included 53 100 women (median age at enrollment 50 years (IQR 43-60) who were cancer-free and had not undergone hysterectomy in 1995-1996 and were followed-up through 2020. Higher levels of total trihalomethanes (TTHM) were associated with incident uterine cancer and endometrioid tumors specifically, with positive associations observed for some individual trihalomethanes, whereas higher levels of total haloacetic acids were associated with nonendometrioid tumors, while no associations were observed for nitrate, arsenic, or uranium. The authors conclude that these findings suggest that lon-term exposure to certain disinfection byproducts may increase the risk of uterine cancer.