title: Measured Prenatal and Estimated Postnatal Levels of Polychlorinated Biphenyls (PCBs) and ADHD-Related Behaviors in 8-Year-Old Children.
abstract: BACKGROUND
  Epidemiologic studies of postnatal PCB exposure and behavior have not reported consistent evidence of adverse associations, possibly because of challenges in exposure estimation. We previously developed a pharmacokinetic model to improve estimation of children's PCB exposure.
  
  
  OBJECTIVE
  We aimed to assess whether estimated serum PCB levels in infancy are associated with attention deficit/hyperactivity disorder (ADHD)-related behaviors at 8 years of age among children whose cord serum PCB levels were previously shown to be associated with ADHD-related behaviors.
  
  
  METHODS
  We used a pharmacokinetic model to estimate monthly serum polychlorinated biphenyl (PCB)-153 levels in 441 infants (ages 1-12 months) based on parameters such as breastfeeding and cord serum PCB-153 levels. Behavior was evaluated at age 8 using the Conners' Rating Scale for Teachers (CRS-T). Associations between PCB-153 levels and ADHD-related CRS-T indices were assessed using multivariable quantile regression at the 50th and 75th percentiles of CRS-T scores, where higher percentiles reflect more adverse behaviors.
  
  
  RESULTS
  Cord serum PCB-153 levels (median, 38 ng/g lipids) were associated with ADHD-related behaviors, although statistical significance was observed with quantile regression models only at the 75th percentile. Associations with postnatal exposure estimates were attenuated. For example, hyperactive-impulsive behavior scores at age 8 years were 0.9 points (95% CI: 0.2, 2.5), 0.5 points (95% CI: 0.3, 2.3), and 0.3 points (95% CI: -0.2, 1.5) higher in association with interquartile range increases in serum PCB-153 at birth, 2 months, and 12 months of age, respectively.
  
  
  CONCLUSIONS
  Associations between estimated postnatal PCB-153 exposures and ADHD-related behaviors at 8 years of age were weaker than associations with PCB-153 concentrations measured in cord serum at birth.
  
  
  BACKGROUND
  Verner MA, Hart JE, Sagiv SK, Bellinger DC, Altshul LM, Korrick SA. 2015. Measured prenatal and estimated postnatal levels of polychlorinated biphenyls (PCBs) and ADHD-related behaviors in 8-year-old children. Environ Health Perspect 123:888-894; http://dx.doi.org/10.1289/ehp.1408084.
authors.affiliation: Channing Division of Network Medicine, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Marc-André
authors.initials: MA
authors.lastname: Verner
authors.forename: Jaime E
authors.initials: JE
authors.lastname: Hart
authors.forename: Sharon K
authors.initials: SK
authors.lastname: Sagiv
authors.forename: David C
authors.initials: DC
authors.lastname: Bellinger
authors.forename: Larisa M
authors.initials: LM
authors.lastname: Altshul
authors.forename: Susan A
authors.initials: SA
authors.lastname: Korrick
mesh_terms: D001289:Attention Deficit Disorder with Hyperactivity / Q000097:blood* / Q000453:epidemiology; D001942:Breast Feeding; D002648:Child; D002675:Child, Preschool; D004785:Environmental Pollutants / Q000097:blood*; D005260:Female; D006801:Humans; D007223:Infant; D008137:Longitudinal Studies; D008297:Male; D008404:Massachusetts / Q000453:epidemiology; D018811:Maternal Exposure; D011078:Polychlorinated Biphenyls / Q000097:blood* / Q000493:pharmacokinetics; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000097:blood / Q000453:epidemiology
chemical_list: D004785:Environmental Pollutants; D011078:Polychlorinated Biphenyls