Association of prenatal co-exposure to OPEs and PAEs with ASD symptom trajectories in preschool children: the modifying role of vitamin D.

INTRODUCTION: Few studies have examined prenatal co-exposure to organophosphate esters (OPEs) and phthalic acid esters (PAEs) in relation to childhood autism spectrum disorder (ASD) symptoms, and whether vitamin D modifies these associations. METHODS: Included 2400 mother-child dyads from the Ma'anshan Birth Cohort and examined levels of maternal OPEs, PAEs, and vitamin D across the three trimesters. Used the Clancy Autism Behavior Scale to assess preschoolers' ASD symptoms at ages 3, 5, and 6, then used group-based trajectory modeling to fit ASD symptom trajectories. RESULTS: ASD symptom scores fit 3 trajectories: low, moderate, and high. Average-MEOHP, average-ΣHMWP, first-trimester-ΣHMWP, third-trimester-DPHP, and third-trimester-BCIPP were associated with increased risk in the moderate group (p < 0.05). Average-MMP, average-ΣHMWP, second-trimester-BEHP, and third-trimester-ΣHMWP were associated with increased risk in the high-score group (p < 0.05). By contrast, first-trimester-BCIPP was negatively correlated with the moderate group. DPHP, DBP, and Σdi-OPEs showed sex-specific effects (psex-int < 0.05). Maternal vitamin D levels modified these associations, with women with vitamin D deficiency showing significantly higher risks. OPEs and PAEs showed mixed effects. CONCLUSION: Prenatal exposure to OPEs/PAEs exhibited heterogeneous associations with preschoolers' ASD symptom trajectories, and maternal vitamin D deficiency exacerbates the effects of OPEs/PAEs individual exposure on symptom trajectories.