Association of Blood Trihalomethane Concentrations with Risk of All-Cause and Cause-Specific Mortality in U.S. Adults: A Prospective Cohort Study

Water chlorination can lead to the formation of disinfection byproducts, including trihalomethanes (THMs). However, few epidemiologic studies have explored associations between THM exposure and mortality. This study included 6720 adults aged ≥40 years from National Health Nutrition Examination Survey 1999–2012 who had blood concentrations quantified. A higher risk all-cause mortality was found across increasing quartile chloroform (TCM) total THMs (TTHMs; sum all four THMs) (both p for trend = 0.02). Adults in highest TCM TTHM hazard ratios (HRs) 1.35 (95% confidence intervals: 1.05–1.74) 1.37 (1.05–1.79), respectively, mortality, compared with lowest quartile. When cause-specific evaluated, a positive relationship bromodichloromethane (BDCM), dibromochloromethane (DBCM), bromoform (TBM), brominated (Br-THMs; BDCM, DBCM, TBM), cancer death TTHMs other cause (noncancer/nonheart disease) Our findings suggest that Br-THMs associated increased risk, whereas greater noncancer/nonheart disease