Positive Association Between Blood Trihalomethane Concentrations and Non-Alcoholic Fatty Liver Disease: A Cross-Sectional Study (NHANES)

Background: Trihalomethanes (THMs) is a common byproduct of disinfection that has been shown to be hepatotoxic. However, the relationship between THMs and non-alcoholic fatty liver disease (NAFLD) remains unclear. Methods: This study selected 9475 adults from the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2012, and the concentrations of various THMs including chloroform (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM), and bromoform (TBM) in their blood were analyzed. NAFLD was identified based on the levels of the fatty liver index (FLI), Alanine Aminotransferase (ALT), and Aspartate Aminotransferase (AST). Results: In the multiple logistic regression model, we found TBM, Br-THM and TTHM concentrations were significantly positively correlated with NAFLD, The odds ratios (ORs) were 1.27 (95% CI 1.07-1.50), 1.19 (95% CI 1.01-1.40), and 1.27 (95% CI 1.07-1.52), respectively, indicating the risk of NAFLD was on the rise with the increase of these THM concentrations. Although the ORs of blood TCM and Cl-THM concentrations were not significant, there was a trend suggesting an increased risk of NAFLD with the increase of their concentrations. Conclusion: This study suggested that THMs exposure is associated with NAFLD in the USA population, and more prospective studies are still needed to confirm this finding and elucidate the underlying mechanisms in the future.