title: Phthalate concentrations in house dust in relation to autism spectrum disorder and developmental delay in the CHildhood Autism Risks from Genetics and the Environment (CHARGE) study.
abstract: BACKGROUND
  Phthalates are endocrine-disrupting chemicals that influence thyroid hormones and sex steroids, both critical for brain development.
  
  
  OBJECTIVE
  We studied phthalate concentrations in house dust in relation to the risks of developing autism spectrum disorder (ASD) or developmental delay (DD).
  
  
  METHODS
  Participants were a subset of children from the CHARGE (CHildhood Autism Risks from Genetics and the Environment) case-control study. ASD and DD cases were identified through the California Department of Developmental Services system or referrals; general population controls were randomly sampled from state birth files and frequency-matched on age, sex, and broad geographic region to ASD cases. All children (50 ASD, 27 DD, 68 typically developing (TD)) were assessed with Mullen Scales of Early Learning, Vineland Adaptive Behavior Scales (VABS) and Aberrant Behavior Checklist. We measured 5 phthalates in dust collected in the child's home using a high volume small surface sampler.
  
  
  RESULTS
  None of the phthalates measured in dust was associated with ASD. After adjustment, we observed greater di(2-ethylhexyl) phthalate (DEHP) and butylbenzyl phthalate (BBzP) concentrations in indoor dust from homes of DD children: Odds ratios (OR) were 2.10 (95% confidence interval (CI); 1.10; 4.09) and 1.40 (95% CI; 0.97; 2.04) for a one-unit increase in the ln-transformed DEHP and BBzP concentrations, respectively. Among TD children, VABS communication, daily living, and adaptive composite standard scores were lower, in association with increased diethyl phthalate (DEP) concentrations in dust. Participants with higher dibutyl phthalate (DBP) concentrations in house dust also trended toward reduced performance on these subscales. Among ASD and DD boys, higher indoor dust concentrations of DEP and DBP were associated with greater hyperactivity-impulsivity and inattention.
  
  
  CONCLUSIONS
  House dust levels of phthalates were not associated with ASD. The inability to distinguish past from recent exposures in house dust and the fact that house dust does not capture exposure from all sources, limit the interpretation of both positive and null findings and further work is needed. However, the associations observed for DEP and DBP with impairments in several adaptive functions and greater hyperactivity, along with evidence for increased risk of DD raise concerns that these chemicals may affect neurodevelopment in children.
authors.affiliation: Divisions of Epidemiology and of Environmental and Occupational Health, Department of Public Health Sciences, School of Medicine, University of California, Davis, CA, USA. cphilippat@ucdavis.edu.|MIND Institute, University of California, 2825 50th Street, Sacramento, CA, 95817, USA. cphilippat@ucdavis.edu.
authors.forename: Claire
authors.initials: C
authors.lastname: Philippat
authors.affiliation: Divisions of Epidemiology and of Environmental and Occupational Health, Department of Public Health Sciences, School of Medicine, University of California, Davis, CA, USA.
authors.forename: Deborah H
authors.initials: DH
authors.lastname: Bennett
authors.affiliation: Divisions of Epidemiology and of Environmental and Occupational Health, Department of Public Health Sciences, School of Medicine, University of California, Davis, CA, USA.|MIND Institute, University of California, 2825 50th Street, Sacramento, CA, 95817, USA.
authors.forename: Paula
authors.initials: P
authors.lastname: Krakowiak
authors.affiliation: Divisions of Epidemiology and of Environmental and Occupational Health, Department of Public Health Sciences, School of Medicine, University of California, Davis, CA, USA.|MIND Institute, University of California, 2825 50th Street, Sacramento, CA, 95817, USA.
authors.forename: Melissa
authors.initials: M
authors.lastname: Rose
authors.affiliation: Department of Civil and Environmental Engineering, University of California, Davis, CA, USA.|Department of Environmental and Interdisciplinary Sciences, Texas Southern University, Houston, TX, USA.
authors.forename: Hyun-Min
authors.initials: HM
authors.lastname: Hwang
authors.affiliation: Divisions of Epidemiology and of Environmental and Occupational Health, Department of Public Health Sciences, School of Medicine, University of California, Davis, CA, USA.|MIND Institute, University of California, 2825 50th Street, Sacramento, CA, 95817, USA.
authors.forename: Irva
authors.initials: I
authors.lastname: Hertz-Picciotto
mesh_terms: D016902:Air Pollution, Indoor / Q000009:adverse effects* / Q000032:analysis; D001321:Autistic Disorder / Q000139:chemically induced* / Q000453:epidemiology; D002140:California / Q000453:epidemiology; D016022:Case-Control Studies; D002675:Child, Preschool; D002658:Developmental Disabilities / Q000139:chemically induced* / Q000453:epidemiology; D004391:Dust / Q000032:analysis*; D004781:Environmental Exposure / Q000009:adverse effects* / Q000032:analysis; D004785:Environmental Pollutants / Q000009:adverse effects* / Q000032:analysis; D005260:Female; D006801:Humans; D008297:Male; D016017:Odds Ratio; D010795:Phthalic Acids / Q000032:analysis*
chemical_list: D004391:Dust; D004785:Environmental Pollutants; D010795:Phthalic Acids; C032279:phthalic acid