Trihalomethanes Exposure Through Drinking Water and Low Birth Weight Risk in Kaunas Cohort

Abstract

ISEE-0071 Background and Objective: Recent epidemiological studies of the relationship between disinfection by-products, as measured by trihalomethanes (THM) in drinking water, and adverse birth outcomes have reported inconsistent and inconclusive findings. In the current study, we examined whether chronic maternal exposures to THM through drinking water have an effect on low birth weight (LBW) risk. Methods: We conducted a prospective cohort study (N = 2744) and analyzed LBW incidence in 2008 Kaunas offspring. Residential tap water samples were collected as part of a cohort study being conducted in Kaunas city, Lithuania. All water samples were collected using identical procedures and tested at a single laboratory. We computed an average THM level from multiple tap water samples taken in the areas covered by four water companies, and these levels linked to female residential district and water usage questionnaire data. We classified THM exposure into three categories based on THM concentration and individual drinking water consumption. We used multivariate logistic regression to estimate adjusted odds ratios (OR) and their 95% confidence intervals (CI) for LBW while controlling for selected covariates. Results: Adjusting for gestational age, maternal smoking, family status and education, we found a dose-related trend towards increasing LBW risk with increasing THM exposure. Adjusted OR was 1.32; 95% CI 0.76–2.29 for moderate, and OR 1.61; 95% CI 1.00–2.72 for high THM exposure. Conclusion: This study provides some evidence for an association between exposures to THM through drinking water and LBW risk.