A new scientific study published online on December 10, 2014 in the peer-reviewed journal Environmental Health investigates the association between prenatal exposure to various endocrine disrupting chemicals (EDCs) and thyroid hormone levels in newborns. De Cock and colleagues from the VU University Amsterdam, the Netherlands measured dichlorodiphenyldichloroethylene (DDE, CAS 72-55-9), three metabolites of di-2-ethylhexyl phthalate (DEHP, CAS 117-81-7), hexachlorobenzene (HCB, CAS 118-74-1), polychlorinated biphenyl (PCB-153, CAS 35065-27-1), and two perfluorinated alkyl acids (PFAAs), namely perfluorooctanesulfonic acid (PFOS, CAS 1763-23-1) and perfluorooctanoic acid (PFOA, CAS 335-67-1) in cord plasma or breast milk. DEHP and both target PFAAs are used in food contact. Further, the main thyroid hormone called T4 was determined in blood collected using the heel-prick method via the Dutch neonatal screening programme. A total of 83 mother-child pairs were included in the analysis. The researchers report that for DDE and PFOA, the highest exposed girls showed an increased T4 level compared to the least exposed girls. This difference has remained significant after adjusting the model for covariates. In boys, no associations were significant in the fully adjusted regression model. No effects on T4 were observed for the remaining target substances. The authors conclude that DDE and PFAAs may be associated with T4 levels in a sex-specific manner. Nevertheless, they point out that the study population was relatively small. Therefore, a confirmation from larger studies is necessary.
de Cock, M. et al. (2014). “Prenatal exposure to endocrine disrupting chemicals in relation to thyroid hormone levels in infants – a Dutch prospective cohort study.” Environmental Health (published online December 10, 2014)