Water Disinfection By-products and the Risk of Congenital Anomalies in Kaunas

There is growing evidence from epidemiological studies that maternal exposure to increased drinking water chlorination with by-products – trihalometane (THM) may be associated with congenital anomalies. The aim of this study was to evaluate the impact of maternal exposure during pregnancy to individual THM internal dose effect on the risk of congenital anomalies. We conducted a population-based prospective study of 3074 Kaunas residents births in 2007–2009, using THM exposure estimated as internal dose. We used multivariate logistic regression analysis and compared the risk of any congenital anomalies in four exposure categories of THM internal dose quartiles. In addition, we conducted a linear regression models analysis with adjustment for maternal physiology, lifestyle and sociodemographic characteristics. Effect estimates based on total THMs and chloroform quartiles tended to increase congenital anomalies risk, but there was no statistically significant effect. However, we found dose–response relationships for the bromodichloromethane (BDCM) internal dose and risk for any congenital anomalies. The adjusted odds ratio for fourth quartile vs. first quartile was 1.5, 95% CI 1.00–2.55. The OR per every 0.01 μg/d increase in BDCM internal dose was 1.03, 95% CI 1.00–1.07. Effect estimates associated with dibromochloromethane (DBCM) exposure levels also revealed statistically significant association with the congenital anomalies risk (OR 1.23, 95% CI 1.02-1.48). The present study suggests that prenatal exposure to total THM has tendency to increase the risk of any congenital anomalies, while exposure to BDCM and DBCM statistically represents a significant increase in the risk of any congenital anomaly. DOI: http://dx.doi.org/10.5755/j01.erem.61.3.1147