Association between maternal organophosphate flame retardants (OPFRs) metabolite levels during pregnancy and internalizing and externalizing behaviors in children at 2-5 years.

Background: Organophosphorus flame retardants (OPFRs) metabolites are frequently detected in human samples. Their structural similarity to polybrominated diphenyl ethers raises concerns about potential neurotoxicity. Animal and limited human studies suggest prenatal exposure to OPFRs may affect offsprings' neurobehavioral problems. Objectives: We investigated the association between maternal OPFRs exposure and neurobehavioral problems in children aged two to five years from the South African Drakenstein Child Health Study (N=705). Methods: We measured urinary metabolites of OPFRs, bis(1,3-dichloro-2-propyl) phosphate (BDCPP) and diphenyl phosphate (DPHP) during the 2 Results: At 24 months, each standard deviation (SD) increase in log-BDCPP levels was associated with higher externalizing (1.26, 95% CI: 0.30, 2.21) and internalizing (1.14, 95% CI: 0.02, 2.25) subscores. Similarly, one SD increase in log-DPHP was associated with higher externalizing (+1.19, 95% CI: 0.23, 2.16) and internalizing (1.00, 95% CI: -0.12, 2.13) subscores. Only DPHP levels were associated with internalizing subscores at 60 months. Conclusion: We observed a positive association between prenatal metabolite levels of OPFRs and neurobehavioral problems among children at age two, raising concerns about prenatal chemical exposures and awareness of developing interventions to promote healthier developmental outcomes for children.