Prenatal bisphenol analogs exposure and placental DNA hypomethylation of genes in the PPAR signaling pathway: Insights for bisphenol analogs' effects on infant anthropometry.

Prenatal exposure to bisphenol analogs (BPs) may pose hazards to offspring's health; however, their underlying mechanisms remain to be elucidated. DNA methylation, a major epigenetic mechanism, may be involved in early programming following environmental disturbances. In this prospective study, we investigated associations between prenatal BPs exposure and the placental DNA methylation levels of 14 candidate genes in the peroxisome proliferator-activated receptor (PPAR) signaling pathway among 205 mother-infant pairs and explored the potential mediating role of the DNA methylation in the association of prenatal BPs exposure with anthropometric measurements of infants aged 1 year. We observed a general pattern that prenatal BPs exposure was associated with the DNA hypomethylation of candidate genes, with associations consistently and notably observed for PPAR α (PPARA), retinoid X receptor α (RXRA), acetyl-CoA acyltransferase 1, and acyl-CoA dehydrogenase medium chain (ACADM) in linear regression and Bayesian kernel machine regression. Both models identified bisphenol F (BPF) as the predominant compound. We found inverse associations between the placental DNA methylation levels of most candidate genes, such as PPARA, RXRA, ACADM, and nuclear receptor subfamily 1 group H member 3 (NR1H3), and the length-for-age z-score, arm circumference-for-age z-score, subscapular skinfold-for-age z-score, and abdominal skinfold thickness of the infants. The DNA methylation levels of RXRA and NR1H3 could mediate the associations between prenatal BPF exposure and increased infant anthropometric measurements, with mediating portions ranging from 23.02% to 30.53%. Our findings shed light on the potential mechanisms underlying the effects of prenatal BPs exposure on infant growth and call for urgent actions for risk assessment and regulation of BPF. Future cohort studies with larger sample sizes are warranted to confirm our findings.