Nationwide evaluation of disinfection byproducts, epigenetics, and birth outcomes.

Regulated US public water systems are a significant source of chronic exposure to contaminants, including disinfection byproducts (DBPs; total trihalomethanes and haloacetic acids). Prenatal DBP exposure is associated with developmental and reproductive toxicity, though existing epidemiologic evidence in the US is limited to small, regional studies. The US Environmental Protection Agency is currently reviewing the existing DBP standards in public water, which are much higher than those set by other nations. One critical gap relevant for revising these regulations is the lack of studies evaluating the association of public drinking water DBPs and adverse birth outcomes.

This research gap persists in part because there were previously no nationwide estimates of public drinking water DBP concentrations available for epidemiologic purposes. Using previously generated, population-weighted, average ZIP Code Tabulation Area (ZCTA)-level public water DBP concentrations, we will evaluate associations between prenatal public water DBPs and adverse birth outcomes across a nationally representative study population. Furthermore, policy and clinical insight is strengthened by understanding the biological mechanisms underlying epidemiologic associations. One accessible biomarker associated with adverse birth outcomes and potentially influenced by DBP exposure is DNA methylation, an epigenetic alteration that affects gene expression.

Early life alterations to DNA methylation by DBPs may modify health and disease trajectories throughout the lifespan. Hence, we propose to leverage nationwide estimates of public water DBP concentrations (2006-2019) in two epidemiologic cohorts with complementary strengths. Our objectives are to evaluate the association of prenatal public water DBP exposure with Aim 1) adverse birth outcomes in >5.4 million registered births in California, Aim 2) adverse birth outcomes in >15,000 births in the ECHO Cohort, and Aim 3) umbilical cord blood DNA methylation patterns for n >1,400 participants in the ECHO Cohort. We will leverage maternal residential address and ZCTA-level DBP exposure estimates to assign mother/infant dyads individual, time-weighted prenatal public drinking water DBP exposures based on gestational timing and residential address ZIP Code.

We propose to evaluate the association of prenatal public water DBP exposure with adverse birth outcomes, with a specific emphasis on estimating effects separately for geographic and socioeconomic status subgroups. The goal of the training plan is to provide the applicant with the skills and experience to conduct rigorous public health research in environmental epidemiology, with a focus on prenatal exposures and epigenetics. The training plan includes a mix of formal didactic training, applied research experience, professional development, and presentation opportunities. Columbia University Mailman School of Public Health is the ideal environment for the proposed project, given the school’s commitment to training students, exceptional expertise, resources available in environmental health sciences and environmental epidemiology, and the unparalleled mentorship team assembled for this proposal.

Grant Number: 1F31ES037209-01
NIH Institute/Center: NIH
Principal Investigator: Tessa Bloomquist