Polybrominated diphenyl ethers in relation to autism and developmental delay: a case-control study

Irva Hertz-Picciotto,Paula Krakowiak,Åke Bergman,Deborah H Bennett,Britta Fängström,Robin Hansen,Isaac Pessah,Melissa Rose

doi:10.1186/1476-069x-10-1

Abstract

BackgroundPolybrominated diphenyl ethers (PBDEs) are flame retardants used widely and in increasing amounts in the U.S. over the last few decades. PBDEs and their metabolites cross the placenta and studies in rodents demonstrate neurodevelopmental toxicity from prenatal exposures. PBDE exposures occur both via breastfeeding and hand-to-mouth activities in small children.MethodsParticipants were 100 children from the CHARGE (CHildhood Autism Risk from Genetics and the Environment) Study, a case-control epidemiologic investigation of children with autism/autism spectrum disorder, with developmental delay and from the general population. Diagnoses of autism were confirmed by the Autism Diagnostic Observation Schedule and Autism Diagnostic Inventory-Revised, and of developmental delay using the Mullen's Scales of Early Learning and the Vineland Adaptive Behavior Scales. Typically developing controls were those with no evidence of delay, autism, or autism spectrum disorder. Eleven PBDE congeners were measured by gas chromatography/mass spectrometry from serum specimens collected after children were assessed. Logistic regression was used to evaluate the association between plasma PBDEs and autism.ResultsChildren with autism/autism spectrum disorder and developmental delay were similar to typically developing controls for all PBDE congeners, but levels were high for all three groups.ConclusionsPlasma samples collected post-diagnosis in this study may not represent early life exposures due to changes in diet and introduction of new household products containing PBDEs. Studies with direct measurements of prenatal or infant exposures are needed to assess the possible causal role for these compounds in autism spectrum disorders.

Highlights

Polybrominated diphenyl ethers (PBDEs) are flame retardants used widely and in increasing amounts in the U.S over the last few decades
The mothers of children with AU/autism spectrum disorders (ASD) were more likely than the mothers from either the developmental delay (DD) or typically developing children to have had some college education (p = 0.03), while mothers of the DD children were the most likely to have had no education beyond high school
A weakness in this pilot study was the examination of current levels of PBDEs as a proxy for exposures that preceded the neuropathologic changes leading to autism

Summary

Introduction

Polybrominated diphenyl ethers (PBDEs) are flame retardants used widely and in increasing amounts in the U.S over the last few decades. Polybrominated diphenyl ethers (PBDEs) are flame retardants used widely in carpeting, foam furniture and car seats, textiles, plastic casings for television sets and computers, household appliances, and construction materials. A body of evidence has accumulated from experimental animal studies showing adverse neurodevelopmental consequences following prenatal and early life exposures [11,12,13,14]. These include hyperactivity and permanent alterations in spontaneous behaviors, deficits in learning and memory, and failure to habituate to novel stimuli, with effects seen at exposure levels comparable to those observed in humans [14]. Exposures on postnatal days 3 and 10, but not postnatal day 19 altered motor behaviors, suggesting specific windows of vulnerability that translate to prenatal periods in humans [12]

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