Prenatal environmental chemical exposures and longitudinal patterns of child neurobehavior

Abstract

Background: Prenatal chemical exposures may adversely affect neurodevelopment, but few studies have examined the persistence of these associations. We examined whether associations between prenatal bisphenol A (BPA) or polybrominated diphenyl ether (PBDE) exposures persist or resolve as children age.

Methods: We followed 346 mother-child pairs (enrolled 2003-2006) from Cincinnati, OH from pregnancy until children were 8 years old. We measured BPA in urine collected at 16 and 26 weeks gestation and PBDE-47 in serum collected at 16 weeks gestation. We administered repeated measures of children's behavior, mental/psychomotor development, and IQ from ages 1-8 years. We determined if associations of BPA or PBDE-47 with child neurobehavior persisted or resolved as children aged using linear mixed models and estimated neurobehavioral measure reproducibility using intraclass correlation coefficients (ICCs).

Results: Higher BPA in girls and higher PBDE-47 in both boys and girls were associated with more externalizing behaviors; these associations persisted from ages 2-8 years (exposure×age interaction p-values≥0.36). Higher PBDE-47 concentrations were associated with decreases in MDI from ages 1-3 years (PBDE-47x age interaction p-value=0.03) and persistently lower IQ at ages 5 and 8 years (PBDE-47×age interaction p-value=0.56). Mental/psychomotor abilities had fair reproducibility from ages 1-3 years (ICCs∼0.4), cognitive abilities from ages 5 to 8 years had excellent reproducibility (ICCs=0.7-0.8), and parent-reported behaviors from ages 2-8 years had poor to good reproducibility (ICCs=0.38-0.59).

Conclusions: Prenatal BPA and PBDE-47 concentrations were persistently associated with more externalizing behaviors. PBDE-47 concentrations were inversely associated with cognitive abilities that strengthened over time.

Keywords: Bisphenol A; Children; Epidemiology; Halogenated flame retardants; Neurodevelopment; Prenatal.

Conflict of interest statement

Competing financial interests: The authors have no competing financial interests to declare.

Copyright © 2017 Elsevier B.V. All rights reserved.

Figures

Figure 1

Average and subject-specific BASC-2 externalizing behavior scores among HOME Study girls between ages 2 and 8 years by prenatal urinary BPA concentration tercilea,b a-Adjusted for maternal age at delivery, maternal race (white or non-white), maternal education (college, some college, ≤ high school), marital status (married or unmarried), serum cotinine concentrations during pregnancy, household income, materna IQ, maternal depressive symptoms at baseline, and caregiving environment score b-A linear mixed model was used to estimate the average and subject-specific change in externalizing scores from 2–8 years of age in each tercile of prenatal urinary BPA concentrations. The thicker lines show the average trajectory in each BPA tercile, while the individual lines show the subject-specific change for each of the 148 girls. The model included an age × BPA interaction term, which allows BASC-2 scores to change as a linear function of both age and BPA tercile. This interaction term was not significant (p-value=0.36), indicating that externalizing scores did not increase or decrease as children aged for a given level of BPA.

Figure 2

Average and subject-specific BASC-2 externalizing behavior, BSID-III MDI, and WPPSI-III/WISC-IV FSIQ scores among HOME Study children between ages 1 and 8 years by prenatal serum PBDE-47 concentration tercilea,b a-Adjusted for maternal age at delivery, maternal race (white or non-white), maternal education (college, some college, ≤ high school), marital status (married or unmarried), serum cotinine concentrations during pregnancy, household income, maternal IQ, maternal depressive symptoms at baseline, and caregiving environment score b-A linear mixed model was used to estimate the average and subject-specific change in externalizing scores (n=251) from age 2–8 years, mental development scores from age 1–3 years (n=250), and full scale IQ from age 5–8 years (n=154) in each tercile of prenatal serum PBDE-47 concentration. The thicker lines show the average trajectory of score in each PBDE-47 tercile, while the individual lines show the subject-specific change for each child. Each model included an age × PBDE-47 interaction term, which allowed the scores to change as a linear function of both age in each PBDE-47 tercile. This interaction term was not significant for externalizing (p-value=0.67) or full scale IQ scores (p-value=0.56), but was for mental development scores (p-value=0.04).