Associations between prenatal and childhood PBDE exposure and early adolescent visual, verbal and working memory

Abstract

Background: Prenatal and childhood exposure to polybrominated diphenyl ether (PBDE) flame retardants has been inversely associated with cognitive performance, however, few studies have measured PBDE concentrations in samples collected during both prenatal and postnatal periods.

Methods: We examined prenatal (cord) and childhood (ages 2, 3, 5, 7 and 9 years) plasma PBDE concentrations in relation to memory outcomes assessed between the ages of 9 and 14 years. The study sample includes a subset (n = 212) of the African American and Dominican children enrolled in the Columbia Center for Children's Environmental Health Mothers and Newborns birth cohort. We used multivariable linear regression to examine associations between continuous log₁₀-transformed PBDE concentrations and performance on tests of visual, verbal and working memory in age-stratified models. We additionally used latent class growth analysis to estimate trajectories of exposure across early life, which we analyzed as a categorical variable in relation to memory outcomes. We examined interactions between PBDE exposure and sex using cross-product terms.

Results: Associations between prenatal exposure and working memory significantly varied by sex (p-interaction = 0.02), with inverse relations observed only among girls (i.e. β_BDE-47 = -7.55, 95% CI: -13.84, -1.24). Children with sustained high concentrations of BDEs-47, 99 or 100 across childhood scored approximately 5-8 standard score points lower on tests of visual memory. Children with PBDE plasma concentrations that peaked during toddler years performed better on verbal domains, however, these associations were not statistically significant.

Conclusions: Exposure to PBDEs during both prenatal and postnatal periods may disrupt memory domains in early adolescence. These findings contribute to a substantial body of evidence supporting the developmental neurotoxicity of PBDEs and underscore the need to reduce exposure among pregnant women and children.

Keywords: Childhood; Flame retardant; Memory; PBDE; Prenatal; Trajectory.

Figure 1.

Diagram of study enrollment and follow-up.

Figure 2.. Distribution of plasma PBDE concentrations (ng/g lipid) by study visit (n=903 data points from 334 children).

PBDE concentrations with a value less than the limit of detection (

Figure 3.. Point estimates (ß) and 95% CIs from adjusted models examining continuous, log₁₀-transformed plasma PBDE concentrations (ng/g lipid) in relation to Attention Concentration Index (ACI), Visual Memory Index (ViMI), and Verbal Memory Index (VeMI) scores

Hollow diamonds indicate girls, hollow squares indicate boys, solid circles indicate boys and girls. PBDEs measured at ages 2 and 5 years were not included due to small sample sizes at these ages. Sample size for ViMI and VeMI models: prenatal (n=208), age 3-years (n=70), age 7-years (n=158), age 9-years (n=128). Sample size for ACI models: prenatal (n=194), age 3-years (n=63), age 7-years (n=144), age 9-years (n=116).

Figure 4.. Point estimates (ß) and 95% CIs from adjusted models examining trajectories of plasma PBDE concentrations in relation to Attention Concentration Index (ACI), Visual Memory Index (ViMI), and Verbal Memory Index (VeMI) scores (n=212).

See Supplemental Material, Figure S2, which plots PBDE trajectories.