Prenatal and childhood perfluoroalkyl substances exposures and children's reading skills at ages 5 and 8years

Abstract

Background: Exposure to perfluoroalkyl substances (PFASs) may impact children's neurodevelopment.

Objective: To examine the association of prenatal and early childhood serum PFAS concentrations with children's reading skills at ages 5 and 8years.

Methods: We used data from 167 mother-child pairs recruited during pregnancy (2003-2006) in Cincinnati, OH, quantified prenatal serum PFAS concentrations at 16±3weeks of gestation and childhood sera at ages 3 and 8years. We assessed children's reading skills using Woodcock-Johnson Tests of Achievement III at age 5years and Wide Range Achievement Test-4 at age 8years. We used general linear regression to quantify the covariate-adjusted associations between natural log-transformed PFAS concentrations and reading skills, and used multiple informant model to identify the potential windows of susceptibility.

Results: Median serum PFASs concentrations were PFOS>PFOA>PFHxS>PFNA in prenatal, 3-year, and 8-year children. The covariate-adjusted general linear regression identified positive associations between serum PFOA, PFOS and PFNA concentrations and children's reading scores at ages 5 and 8years, but no association between any PFHxS concentration and reading skills. The multiple informant model showed: a) Prenatal PFOA was positively associated with higher children's scores in Reading Composite (β: 4.0, 95% CI: 0.6, 7.4 per a natural log unit increase in exposure) and Sentence Comprehension (β: 4.2, 95% CI: 0.5, 8.0) at age 8years; b) 3-year PFOA was positively associated with higher children's scores in Brief Reading (β: 7.3, 95% CI: 0.9, 13.8), Letter Word Identification (β: 6.6, 95% CI: 1.1, 12.0), and Passage Comprehension (β: 5.9, 95% CI: 1.5, 10.2) at age 5years; c) 8-year PFOA was positively associated with higher children's Word Reading scores (β: 5.8, 95% CI: 0.8, 10.7) at age 8years. Prenatal PFOS and PFNA were positively associated with children's reading abilities at age 5years, but not at age 8years; 3-year PFOS and PFNA were positively associated with reading scores at age 5years. But PFHxS concentrations, at any exposure windows, were not associated with reading skills.

Conclusion: Prenatal and childhood serum PFOA, PFOS and PFNA concentrations were positively associated with better children's reading skills at ages 5 and 8years, but no association was found between serum PFHxS and reading skills.

Keywords: Childhood; Perfluoroalkyl substances (PFASs); Prenatal; Reading skills.

Conflict of interest statement

Competing financial interest declaration

None.

Copyright © 2017 Elsevier Ltd. All rights reserved.

Figures

Figure 1

Medians of PFASs concentrations in prenatal serum, and in children’s serum at ages 3 and 8 years. ^: Bars present the p75 percentile of PFASs concentrations in the HOME Study. We referenced prenatal median serum PFASs concentration (pregnant women or general women, NHANES, 2003–2004) or children’s mean PFAS concentrations (NHANES, 2001–2002, pooled sera from 3–11 years of age children), the IQR or p25 and p75 percentiles was not provided in the publications (Kato et al. 2009; Woodruff et al. 2011). The Kato et al. reported the mean concentrations of the pooled samples in children, it is not the same median as we used in the HOME study.