Gestational phthalate exposure and behavioral problems in preschool-aged children with increased likelihood of autism spectrum disorder

Background

Experimental studies have shown associations between gestational phthalate exposure and behavioral problems among offspring; however, epidemiological evidence is still mixed. This study aims to investigate whether gestational phthalate exposure is associated with behavioral problems in preschool-aged children.

Methods

Participants include 178 mother-child pairs from MARBLES (Markers of Autism Risk in Babies – Learning Early Signs), a cohort with high familial likelihood of autism spectrum disorder (ASD). We quantified 14 phthalate metabolites in multiple maternal urine samples collected during the 2nd and 3rd trimesters. Preschool behavior problems were assessed using the Child Behavioral Checklist (CBCL), a standardized instrument for evaluating behavior problems of children aged 1.5–5 years. To examine associations of CBCL scores with both individual phthalate biomarker concentrations and their mixture, we used negative binomial regression and weighted quantile sum regression.

Results

Overall, maternal phthalate biomarker concentrations were not associated with child behavior problems. Monoisobutyl phthalate (MiBP) concentrations were inversely associated with child anxious/depressed symptoms and somatic complaints. Mono-hydroxy-isobutyl phthalate (MHiBP) and monobenzyl phthalate (MBzP) were also inversely associated with somatic complaints. When assessing trimester-specific associations, more behavior problems were associated with the 2nd trimester biomarker concentrations: mono(3-carboxypropyl) phthalate (MCPP) and monocarboxyisononyl phthalate (MCNP) were positively associated with somatic complaints. All associations became non-significant after false discovery rate correction. No association between a mixture of phthalates and CBCL scores was found.

Conclusions

Our study observed no clear evidence of gestational phthalate exposure on child behavior problems. However, our findings based on the biomonitoring assessment of multiple samples per participant could improve our understanding of gestational phthalate exposure in association with behavior problems in preschool-aged children.