Prenatal exposure to endocrine disrupting chemical mixtures and infant birth weight: A Bayesian analysis using kernel machine regression

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DOI

https://doi.org/10.1016/j.envres.2021.110749

Language of the publication
English
Date
2021-01-17
Type
Article
Author(s)
  • Hu, Janice M.Y.
  • Arbuckle, Tye E.
  • Janssen, Patricia A.
  • Lanphear, Bruce P.
  • Zhuang, Liheng H.
  • Braun, Joseph M.
  • Chen, Aimin
  • McCandless, Lawrence C.
Publisher
Elsevier

Abstract

Background Pregnant women are regularly exposed to a multitude of endocrine disrupting chemicals (EDCs). EDC exposures, both individually and as mixtures, may affect fetal growth. The relationship of EDC mixtures with infant birth weight, however, remains poorly understood. We examined the relations between prenatal exposure to EDC mixtures and infant birth weight. Methods We used data from the Maternal-Infant Research on Environmental Chemicals (MIREC) Study, a pan-Canadian cohort of 1857 pregnant women enrolled between 2008 and 2011. We quantified twenty-one chemical concentrations from five EDC classes, including organochlorine compounds (OCs), metals, perfluoroalkyl substances (PFAS), phenols and phthalate metabolites that were detected in >70% of urine or blood samples collected during the first trimester. In our primary analysis, we used Bayesian kernel machine regression (BKMR) models to assess variable importance, explore EDC mixture effects, and identify any interactions among EDCs. Our secondary analysis used traditional linear regression to compare the results with those of BKMR and to quantify the changes in mean birth weight in relation to prenatal EDC exposures. Results We found evidence that mixtures of OCs and metals were associated with monotonic decreases in mean birth weight across the whole range of exposure. trans-Nonachlor from the OC mixture and lead (Pb) from the metal mixture had the greatest impact on birth weight. Our linear regression analysis corroborated the BKMR results and found that a 2-fold increase in trans-nonachlor and Pb concentrations reduced mean birth weight by −38 g (95% confidence interval (CI): −67, −10) and −39 g (95% CI: −69, −9), respectively. A sex-specific association for OC mixture was observed among female infants. PFAS, phenols and phthalates were not associated with birth weight. No interactions were observed among the EDCs. Conclusions Using BKMR, we observed that both OC and metal mixtures were associated with decreased birth weight in the MIREC Study. trans-Nonachlor from the OC mixture and Pb from the metal mixture contributed most to the adverse effects.

Plain language summary

"Health Canada is responsible for the assessment and management of health risks, including those associated with exposure to chemicals in the environment. Pregnant women are often exposed to a mixture of potential endocrine disrupting chemicals that may affect infant birth weight. While considerable research has been done on individual chemicals and their association with birth weight, studies of chemical mixtures are limited. The objective of this study was to examine the association between prenatal exposure to chemical mixtures and infant birth weight. Data from the Maternal-Infant Research on Environmental Chemicals (MIREC) Study were analysed, composed of 1857 pregnant women and their infants. Twenty-one different chemicals from five unique groups were measured in 1st trimester blood and urine. These groups were organochlorine compounds (OCs), metals, perfluoroalkyl substances (PFAS), phenols and phthalates. Complex statistical techniques were used to quantify changes in birth weight in relation to maternal levels of chemicals. The researchers found that mixtures of OCs and metals were associated with lower birth weight with trans-nonachlor from the OC group and lead from the metal group having the greatest negative impact on birth weight. A 2-fold increase in maternal blood lead was associated with 38 gram reduction in birth weight. PFAS, phenols and phthalates were not associated with birth weight. In conclusion, this study led by a graduate student at Simon Fraser University, found that higher levels of OC and metal mixtures in maternal blood during the 1st trimester were associated with lower birth weight. "

Subject

  • Health,
  • Health and safety

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Healthy environments, consumer safety and consumer products

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