Prenatal Polybrominated Diphenyl Ether (PBDE) Exposure and Social Cognition at Age 14
Objectives: To examine the influence of prenatal exposure to PBDEs on social cognition, a trait impaired in individuals with ASD, in early adolescence.
Methods: We measured concentrations of 4 common PBDE congeners (BDE-47, 99, 100, 153) in blood contributed by CHAMACOS mothers during the second half of pregnancy (in 2000-2002). When children were aged 14 years, parents completed the Social Responsiveness Scale, Second Edition (SRS-2), a rating scale of traits related to ASD. Using generalized additive models, we examined associations of serum lipid-adjusted PBDE concentrations in relation to sex-standardized SRS-2 T-scores (population standard mean=50, standard deviation=10), with adjustment for child’s age at SRS-2, breastfeeding duration, household income, maternal characteristics (age, parity, education, country of origin, years in the United States, pre-pregnancy body mass index, and IQ), and measures of maternal depression and support for cognitive development in the home.
Results: 147 children with SRS-2 scores, prenatal PBDE measures, and relevant covariates were included. Median (25%─75%) serum lipid-adjusted PBDE concentrations were: 15.0 ng/g lipid (8.7─24.5) [BDE-47], 3.7 (2.4─6.9) [BDE-99], 2.4 (1.6─4.2) [BDE-100], 2.0 (1.4─3.6) [BDE-153]. SRS-2 T-scores ranged from 41─88 with a mean (standard deviation) of 55.3 (7.8). Relationships of SRS-2 T-scores with log10-tranformed PBDE concentrations appeared linear, and scores were higher (representing more autistic behaviors) among children whose mothers had higher concentrations of BDE-153 in pregnancy (β=3.5; 95% confidence interval (CI): -0.5, 7.5 per 10-fold increase in maternal BDE-153 concentration). SRS-2 scores did not appear associated with the other measured PBDE congeners or the sum of the four PBDE congeners (β=0.7; 95% CI: -3.0, 4.4).
Conclusions: Among young adolescents living in a low-income agricultural community, behaviors related to ASD appeared somewhat elevated in those with higher prenatal exposure to BDE-153, but not other measured PBDEs. BDE-153 is a component of the commercial flame retardants penta- and octabromodiphenyl ethers (penta- and octaBDEs), which were phased out of production in the United States in 2004 due to concerns about potential toxicity, but remain present in older consumer products.