Gestational exposure to endocrine disrupting chemicals in relation to infant birth weight: a Bayesian analysis of the HOME Study
Woods et al. Environmental Health
Gestational exposure to endocrine disrupting chemicals in relation to infant birth weight: a Bayesian analysis of the HOME Study
Meghan M. Woods 0
Bruce P. Lanphear 0 2
Joseph M. Braun 1
Lawrence C. McCandless 0 3
0 Faculty of Health Sciences, Simon Fraser University , Blusson Hall, Rm 11300, 8888 University Drive, Burnaby, British Columbia V5A 1S6 , Canada
1 Department of Epidemiology, Brown University , Box G-S121-2, 121 South Main St, Providence, Rhode Island 02912 , USA
2 Child and Family Research Institute, BC Children's and Women's Hospital , 950 West 28th Avenue, Vancouver, British Columbia V5Z 4H4 , Canada
3 Department of Statistics and Actuarial Science, University of British Columbia, Faculty of Science , 3182 Earth Science Building, 2207 Main Mall, Vancouver, British Columbia V6T 1Z4 , Canada
Background: Pregnant women are exposed to a mixture of endocrine disrupting chemicals (EDCs). Gestational EDC exposures may be associated with changes in fetal growth that elevates the risk for poor health later in life, but few studies have examined the health effects of simultaneous exposure to multiple chemicals. This study aimed to examine the association of gestational exposure to five chemical classes of potential EDCs: phthalates and bisphenol A, perfluoroalkyl substances (PFAS), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and organochlorine pesticides (OCPs) with infant birth weight. Methods: Using data from the Health Outcomes and Measures of Environment (HOME) Study, we examined 272 pregnant women enrolled between 2003-2006. EDC concentrations were quantified in blood and urine samples collected at 16 and 26 weeks gestation. We used Bayesian Hierarchical Linear Models (BHLM) to examine the associations between newborn birth weight and 53 EDCs, 2 organochlorine pesticides (OPPs) and 2 heavy metals. Results: For a 10-fold increase in chemical concentration, the mean differences in birth weights (95% credible intervals (CI)) were 1 g (-20, 23) for phthalates, -11 g (-52, 34) for PFAS, 0.2 g (-9, 10) for PCBs, -4 g (-30, 22) for PBDEs, and 7 g (-25, 40) for OCPs. Conclusion: Gestational exposure to phthalates, PFAS, PCBs, PBDEs, OCPs or OPPs had null or small associations with birth weight. Gestational OPP, Pb, and PFAS exposures were most strongly associated with lower birth weight.
Birth weight; Endocrine disruptors; Environmental exposure; Maternal exposure; Pregnancy
Background
Endocrine disrupting chemicals (EDC) are synthetic
compounds found in many consumer products [
1–3
] that alter
the endocrine system [
4, 5
]. Because they are widely
distributed in the environment, the majority of pregnant
women in the United States have detectable levels of
multiple EDCs in their blood or urine [
6, 7
]. Among EDCs,
broad classes include phthalates and phenols (e.g.,
bisphenol A [BPA]), perfluoroalkyl substances (PFAS),
polychlorinated biphenyls (PCBs), polybrominated diphenyl
ethers (PBDEs), and organochlorine pesticides (OCPs).
Phthalates are used as plasticizers [
1, 4, 5, 8
] and also
found in personal care and consumer products [
1, 3, 7
].
BPA is added to many plastics and consumer
products [
9, 10
]. PFAS are used as stain and water
repellants [
11
], fire fighting foams [
11
] and food contact
material [
3
] while PCBs were used as hydraulic oil
additives [
2
], coolant fluids [
2, 5
] and insulators [12].
PBDEs are flame retardants [
13
] and OCPs are
agricultural pesticides [
5, 14
].
The vulnerability of the developing fetus [
15
] coupled
with the pervasive nature of EDCs has raised concerns
about reproductive health effects arising from gestational
EDC exposure, such as low birth weight [
15
]. Low birth
weight is a predictor for coronary heart disease [
16
],
diabetes mellitus [
17
] and infant mortality [
17
]. Additionally,
some previously published studies [
14, 15
] found
associations between gestational EDC exposure and birth weight.
Understanding the role EDCs may play in affecting birth
weight will inform efforts to prevent low birth weight and
the development of chronic diseases.
Many investigators have explored the relationship
between EDC exposures and birth weight [
18
]. Lenters et al.
examined the relationships between 16 chemicals (6
phthalates, 8 PFAS, 2 PCBs and 1 OCP) and birth weight
using Elastic Net Regression analyses; 2 phthalates, 1
PFAS, and 1 OCP were associated with lower birth weight
[
18
]. Using a job exposure matrix, which can differ from
exposure measurement, Birks et al. (2016) examined
occupational EDC exposures in a meta-analysis of European
birth cohorts and found that pregnant women exposed to
more than 1 EDC class were more likely to have a low
birth weight infant [
15
]. There is sufficient evidence that
increased PFAS (especially PFOA) exposure is associated
with low birth weight [
18–20
], but mixed results are
reported for other EDCs an (...truncated)