Blood trihalomethane concentrations and allergic sensitization: A nationwide cross-sectional study

Background: Exposure to disinfection by-products has been associated with several allergic diseases, but its association with allergen-specific immunoglobulin E (IgE) antibodies remains inconclusive. Methods: We included 932 U.S. adolescents and 2187 adults from the National Health and Nutrition Examination Survey 2005-2006 who had quantified blood THM concentrations [chloroform (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM), and bromoform (TBM)] and 19 allergen-specific IgE antibodies. The odds ratios (ORs) of allergen-specific sensitization per 2.7-fold increment in blood THM concentrations were estimated by multivariable logistic regression models. Results: Blood THM concentrations were unrelated to any allergen-specific sensitization in adults. Among adolescents, however, we found positive associations between blood TCM and chlorinated THMs (Cl-THMs: sum of TCM, BDCM, and DBCM) concentrations and the odds of pet sensitization [OR = 1.28 (95 % CI: 1.05, 1.55) and 1.38 (1.15, 1.65), respectively, per each 2.7-fold increment], between blood BDCM concentrations and the odds of mold [OR = 1.47 (1.24, 1.74)], plant [OR = 1.25 (1.09, 1.43)], pet [OR = 1.27 (1.07, 1.52)], and food sensitization [OR = 1.18 (1.03, 1.36)], and between blood brominated THM (Br-THMs: sum of BDCM, DBCM, and TBM) and total THM (TTHMs: sum of 4 THMs) concentrations and the odds of mold [OR = 1.52 (1.30 1.78) and 1.30 (1.03, 1.65), respectively], dust mite [OR = 1.39 (1.06, 1.82) and 1.45 (1.06, 1.98), respectively], and pet sensitization [OR = 1.42 (1.05, 1.92) and 1.54 (1.19, 1.98), respectively]. Conclusion: Higher blood concentrations of THMs were associated with a greater risk of allergic sensitization among U.S. adolescents but not in adults.