The association between blood trihalomethane concentrations and high risk for prostate cancer: A nationally representative cross-sectional study.

Trihalomethanes (THMs), a class of disinfection byproducts, have been implicated in various health risks. However, their association with prostate cancer (PCa) has not been systematically evaluated in biomarker-based studies. This cross-sectional study investigated associations between blood THMs exposure and both total prostate-specific antigen (tPSA) levels and high risk for PCa status using data from 2319 male participants (≥40 years) in the 2003-2010 National Health and Nutrition Examination Survey (NHANES) cycles. Blood concentrations of bromoform (TBM), chloroform (TCM), bromodichloromethane (BDCM), and dibromochloromethane (DBCM) were measured, and composite indicators for chlorinated (Cl-THMs), brominated (Br-THMs), and total THMs (TTHMs) were calculated. Multivariable regression and weighted quantile sum (WQS) models revealed that exposure to TCM, Cl-THMs, and TTHMs was significantly positively associated with tPSA levels. Additionally, TCM, BDCM, Cl-THMs, and TTHMs were also observed to be closely associated with high risk for PCa. Restricted cubic spline analysis suggested a linear exposure-response trend. WQS results highlighted TCM and BDCM as major contributors to prostate-related risks. Subgroup analyses indicated that age, socioeconomic status, and comorbidities may modify these associations. These findings suggest that THMs exposure may be associated with an elevated risk of PCa, warranting further investigation.