Prenatal phthalate, triclosan, and bisphenol A exposures and child visual-spatial abilities

Abstract

Introduction: During fetal development, sex steroids influence sexually dimorphic behaviors, such as visual-spatial abilities. Thus, endocrine disrupting chemicals that impact sex steroids during gestation may affect these behaviors.

Objective: We investigated the relationship between prenatal urinary phthalate metabolite, triclosan, and BPA concentrations and visual-spatial abilities in a prospective cohort of 198 mother-child dyads.

Methods: Data are from a prospective cohort in Cincinnati, OH (HOME Study). We measured nine phthalate metabolites, triclosan, and BPA in maternal urine samples collected at 16 and 26 weeks of gestation. We assessed children's visual-spatial abilities at 8 years of age using the Virtual Morris Water Maze (VMWM), a computerized version of the rodent Morris Water Maze. We quantified the covariate-adjusted change in the time or distance to complete the VMWM and time spent in the correct quadrant during a probe trial with an interquartile range increase in chemical concentrations using linear mixed models and linear regression, respectively.

Results: Boys completed the VMWM faster (4.1s; 95% CI:-7.1, -1.2) and in less distance (1.4 units; 95% CI:-2.8, 0) than girls. Overall, children with higher mono-n-butyl (MnBP), mono-benzyl (MBzP), and mono-carboxypropyl phthalate concentrations completed the VMWM in less time and distance than children with lower concentrations. For example, children with higher MnBP concentrations completed the VMWM in 0.9 less distance units (95% CI:-1.8, -0.0). Child sex modified the association between MnBP and VMWM performance. In girls, higher MnBP concentrations were associated with longer time (1.7s; 95% CI: -0.7, 4.1) and shorter distance (-1.7 units; 95% CI: -2.8, -0.5), whereas in boys, it was associated with shorter time (-3.0s; 95% CI:-5.6, -0.4), but not distance (-0.1 units; 95% CI:1.4, 1.0). Other phthalate metabolites, triclosan, and BPA were not associated with VMWM performance, and sex did not consistently modify these associations.

Conclusions: In this cohort, greater prenatal urinary concentrations of some phthalate metabolites were associated with improved VMWM performance, particularly among boys. Future studies should confirm these findings and determine if phthalates affect other hormonally sensitive aspects of child neurobehavior.

Keywords: Children; Endocrine disrupting chemicals; Epidemiology; Prenatal; and neurodevelopment.

Copyright © 2016 Elsevier B.V. All rights reserved.

Figures

Figure 1

Adjusted mean difference in latency to complete the VMWM with an interquartile range increase in maternal concentrations of urinary phthalate metabolites, triclosan, or bisphenol A during pregnancya,b *-Abbreviations: BPA: Bisphenol A, TCS: Triclosan, MCPP: mono-carboxypropyl phthalate, MiBP mono-iso-butyl phthalate, MBzP: mono-benzyl phthalate, MnBP: mono-n-butyl phthalate (MnBP), ΣDEHP: sum of di-2-ethylhexyl phthalate metabolites, and MEP: monoethyl phthalate. a- Adjusted for maternal race, maternal age at delivery, marital status, maternal education, parity, household income, serum cotinine concentrations during pregnancy, binge drinking during pregnancy, depressive symptoms during pregnancy, prenatal vitamin use, maternal IQ, and child age at testing. b- The p-values for the interaction terms between child sex and urinary BPA (p=0.74), MCPP (p=0.82), MiBP (p=0.31), MBzP (p=0.62), triclosan (p=0.46), ΣDEHP (p=0.50), and weighted phthalate sum (p=0.47) were not significant, while the p-value for the interaction term between child sex and urinary MnBP (p=0.01) and MEP (p

Figure 2

Adjusted mean difference in distance to complete the VMWM with an interquartile range increase in maternal urinary concentratios of phthalate metabolite, triclosan, or bisphenol A during pregnancya,b *-Abbreviations: BPA: Bisphenol A, TCS: Triclosan, MCPP: mono-carboxypropyl phthalate, MiBP mono-iso-butyl phthalate, MBzP: mono-benzyl phthalate, MnBP: mono-n-butyl phthalate (MnBP), ΣDEHP: sum of di-2-ethylhexyl phthalate metabolites, and MEP: monoethyl phthalate. a- Adjusted for maternal race, maternal age at delivery, marital status, maternal education, parity, household income, serum cotinine concentrations during pregnancy, binge drinking during pregnancy, depressive symptoms during pregnancy, prenatal vitamin use, maternal IQ, and child age at testing. b- The p-values for the interaction terms between child sex and urinary BPA (p=0.57), MCPP (p=0.36), MiBP (p=0.28), triclosan (p=0.28), ΣDEHP (p=0.66), MEP (p=0.28), and weighted phthalate sum (p=0.55) were not significant, while the p-values for the interaction terms between child sex and urinary MBzP (p=0.05) and MnBP (p=0.07) were significant.

Figure 3

Adjusted mean difference in probe trial time with an interquartile range increase in maternal urinary concentrations of phthalate metabolite, triclosan, or bisphenol A during pregnancya,b *-Abbreviations: BPA: Bisphenol A, TCS: Triclosan, MCPP: mono-carboxypropyl phthalate, MiBP mono-iso-butyl phthalate, MBzP: mono-benzyl phthalate, MnBP: mono-n-butyl phthalate (MnBP), ΣDEHP: sum of di-2-ethylhexyl phthalate metabolites, and MEP: monoethyl phthalate. a- Adjusted for maternal race, maternal age at delivery, marital status, maternal education, parity, household income, serum cotinine concentrations during pregnancy, binge drinking during pregnancy, depressive symptoms during pregnancy, prenatal vitamin use, maternal IQ, and child age at testing. b- The p-values for the interaction terms between child sex and urinary BPA (p=0.44), MCPP (p=0.29), MiBP (p=0.44), MBzP (p=0.83) triclosan (p=0.49), ΣDEHP (p=0.82), MEP (p=0.62), and weighted phthalate sum (p=0.90) were not significant, while the p-value for the interaction term between child sex and urinary MnBP (p=0.04) was significant.