Early-life exposure to multiple environmental contaminants and birth outcomes

Abstract

OPS 16: Chemical exposures and birth outcomes, Room 114, Floor 1, August 28, 2019, 10:30 AM - 12:00 PM Background/Aim: Prenatal chemical exposure has frequently been associated with reduced fetal growth although results have been inconsistent. Most studies associate single pollutant exposure to these health outcomes, even though this does not reflect real life situations as humans are exposed to thousands pollutants during their life time. The objective of this study is to investigate the association between prenatal exposure to a mixture of persistent environmental chemicals and birth weight. Methods: We combined exposure biomarker data obtained from cord blood samples of 1579 women from three Flemish birth cohorts (FLEHS I, II & III) and a regional birth cohort (3xG). The common set of available and detectable exposure measures are three polychlorinated biphenyls (PCB) congeners (138, 153 and 180), hexachlorobenzene (HCB), dichlorodiphenyldichloroethylene (p,p’-DDE), cadmium and lead. Multiple linear regression (MLR), Bayesian Information Criterion (BIC), Elastic net (ENET) and Bayesian Adaptive Sampling (BAS) were applied to assess the influence of multiple pollutants on birth weight, adjusted for a priori selected covariates. Results: In the pooled database, birth weight ranged from 1245 to 5575 grams with a median of 3430 grams. The median contaminant levels in cord blood were: 15.8, 26.5, 18.0, 16.9 and 91.5 ng/g lipid for PCB 138, PCB 153, PCB 180, HCB and p,p’-DDE, respectively, 0.075 µg/L for cadmium and 9.7 µg/L for lead. Based on the four applied multipollutant statistical methods, p,p’-DDE and PCB 180 were most consistently associated to birth weight. Additionally, PCB 153 was selected when applying ENET and BAS. An inverse association with birth weight was found for the PCB congeners, while an increased birth weight was observed for elevated levels of p,p’-DDE. Conclusions: Assessing health risk of combinations of exposure biomarkers reflects better real-world situations. The findings allow more effective risk assessment as addressing the critical chemical in a mixture of pollutants is pivotal.