Environment/Climate Change
Exposure to endocrine disrupting chemicals and thyroid function in pregnancy: Data from a NYC birth cohort Akhgar Ghassabian* Akhgar Ghassabian Kristyn Pierce Yelena Afanasyeva Kim Nail Cajachagua Torres Kurunthachalam Kannan Mengling Liu Leonardo Trasande
Thyroid disruption during gestation is linked to adverse health outcomes in pregnant individuals and their offspring. We examined the extent to which exposure to commonly used plasticizers, pesticides, and other endocrine-disrupting chemicals contribute to thyroid disruption in pregnancy.
In 1053 pregnant participants of NYU Children’s Health and Environment Study (2016-2021), we examined urinary concentrations of 2 bisphenols and 13 phthalate, 5 dialkylphosphate (DAP), and 8 polyaromatic hydrocarbons (PAH) metabolites at <18 weeks and 18-25 weeks of gestation. Measures were adjusted for urinary dilation and averaged across timepoints. Serum thyroid parameters were measured at <25 weeks. We examined independent and joint effects of exposure to chemical families on thyroid function using linear regression and partial-linear single-index models. Coefficients were reported as standard deviation change in the log10-transformed molar sums of chemical groups.
In single pollutant analyses, higher exposure to ∑bisphenols was associated with lower total thyroxine (β=-0.17, 95%CI: -0.33, -0.01). Higher exposure to di(2-ethylhexyl) phthalate (∑DEHP) and di-n-octyl phthalate (∑DnOP) were associated with lower free thyroxine (β for ∑DEHP=-0.02, 95%CI: -0.03, -0.01 and β for ∑DnOP =-0.02, 95%CI: -0.03, -0.001) and total thyroxine (β for ∑DEHP=-0.31, 95%CI: -0.47, -0.15 and β for ∑DnOP=-0.23, 95%CI: -0.39, -0.08). No association with thyrotropin was observed. In mixture analyses, there were indications for interaction between chemicals in association with thyroid parameters. We observed no joint effects of chemicals on free thyroxine. Chemicals had an inverse u-shape association with total thyroxine, with major contributions from low molecular weight phthalates, ∑PAH, and ∑DnOP.
These results show exposure to plasticizers may contribute to thyroid dysfunction in pregnancy, supporting the need for regulation of these chemicals.
