Cognitive Deficits and Behavior Problems in Children with Prenatal Polybrominated diphenyl ethers Exposure

BACKGROUND: Polybrominated diphenyl ethers (PBDEs) are persistent chemicals that were widely used as flame retardants in furniture, carpet padding, car seats and other consumer products during the past three decades. Little is known about the impact of prenatal PBDE exposures on children's intellectual abilities or behavioral problems.
OBJECTIVE: To investigate the association between prenatal exposure to PBDEs and child neurodevelopment.
DESIGN/METHODS: We measured maternal serum concentrations of BDE-47 and the sum of 4 PBDE chemicals (-47, -99, -100, -153) in 301 women at 16 weeks of gestation and followed their children annually until 5 years of age in the HOME Study in Cincinnati, OH. We examined the associations with children's cognitive and motor abilities using the Bayley Scales of Infant Development-II at ages 1, 2, 3 years, and intelligence using the Wechsler Preschool and Primary Scale of Intelligence-III at age 5 years. We also investigated the association with children's behaviors using the Behavioral Assessment System for Children-2 at ages 2, 3, 4, and 5 years. We used linear mixed models with adjustment for maternal age, race, education, marital status, serum cotinine, IQ, blood lead, depression score, household income, child sex, and the HOME Inventory, a measure of the nurturing environment of the home. 
RESULTS: Prenatal exposure to BDE-47 and sum4BDEs was associated with cognitive deficits at 2, 3, and 5 years; the deficits were larger in older children. The geometric mean of sum4BDEs was 37 ng/g lipid, with BDE-47 at 20 ng/g lipid, comparable to US national average in the 2003-2004. For a 10-fold increase in BDE-47 there was a -4.6 decrement in Bayley Mental Development Index (95% CI=-8.4, -0.8) at age 3 and a -7.5 decrement in Wechsler Full Scale IQ (95% CI=-11.9, -3.1) at 5 years. Prenatal BDE-47 and sum4BDEs exposure was also associated with an increase in hyperactivity symptoms. A ten-fold increase in BDE-47 was associated with 2.4 increment (95% CI=0.1, 4.6) in hyperactivity score.
CONCLUSIONS: Prenatal exposure to PBDEs, a group of flame retardants that are detectable in virtually all US children, was strongly associated with cognitive deficits and hyperactivity behaviors in children.

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