Associations of prenatal exposure to organophosphate flame retardants and organophosphorus pesticides with cardiac structure in 4-year-old children: Evidence from the Shanghai Birth Cohort.

INTRODUCTION: Organophosphate flame retardants (OPFRs) and organophosphorus pesticides (OPPs) are widely used chemicals in daily environments. Yet, evidence linking prenatal exposure to them with cardiac structure development in offspring is scarce. METHODS: Maternal urinary levels of OPFR and OPP metabolites were measured during the first and second trimesters. Left ventricular end-diastolic volume (LVEDV) and mass (LVM) were assessed by echocardiography in 4-year-old children. Multivariable linear regression and Bayesian kernel machine regression were used to evaluate individual and mixture effects, with sex-stratified and interaction analyses performed to assess potential modification. RESULTS: Among 458 mother-child pairs from the Shanghai Birth Cohort, higher maternal urinary Di-o-cresyl-phosphate (DoCP) concentrations during both trimesters were associated with lower z-scores of LVEDV (β: -0.049, 95% CI: -0.089, -0.008; and β: -0.055, 95% CI: -0.089, -0.022, respectively) and LVM (β: -0.057, 95% CI: -0.098, -0.015; and β: -0.053, 95% CI: -0.087, -0.019, respectively) in 4-year-old offspring. Similarly, higher maternal Di-phenyl phosphate (DPHP) concentration in the second trimester negatively correlated with z-scores of LVEDV (β: -0.043, 95% CI: -0.085, -0.002) and LVM (β: -0.080, 95% CI: -0.122, -0.038). Mixture analyses revealed inverted J-shape associations between maternal mixed OPFRs/OPPs exposure and offspring LVEDV and LVM. Sex-stratified analyses suggested stronger associations among girls. CONCLUSIONS: Prenatal exposure to OPFRs and OPPs was associated with smaller left ventricular structural measures in early childhood, mainly reflected by lower left ventricular volume and mass, with OPFRs emerging as main contributors and stronger associations among girls.