title: Effects of prenatal exposure to air pollutants (polycyclic aromatic hydrocarbons) on the development of brain white matter, cognition, and behavior in later childhood.
abstract: OBJECTIVE
  Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous and neurotoxic environmental contaminants. Prenatal PAH exposure is associated with subsequent cognitive and behavioral disturbances in childhood.
  
  
  OBJECTIVE
  To identify the effects of prenatal PAH exposure on brain structure and to assess the cognitive and behavioral correlates of those abnormalities in school-age children.
  
  
  METHODS
  Cross-sectional imaging study in a representative community-based cohort followed up prospectively from the fetal period to ages 7 to 9 years. The setting was urban community residences and an academic imaging center. Participants included a sample of 40 minority urban youth born to Latina (Dominican) or African American women. They were recruited between February 2, 1998, and March 17, 2006.
  
  
  METHODS
  Morphological measures that index local volumes of the surface of the brain and of the white matter surface after cortical gray matter was removed.
  
  
  RESULTS
  We detected a dose-response relationship between increased prenatal PAH exposure (measured in the third trimester but thought to index exposure for all of gestation) and reductions of the white matter surface in later childhood that were confined almost exclusively to the left hemisphere of the brain and that involved almost its entire surface. Reduced left hemisphere white matter was associated with slower information processing speed during intelligence testing and with more severe externalizing behavioral problems, including attention-deficit/hyperactivity disorder symptoms and conduct disorder problems. The magnitude of left hemisphere white matter disturbances mediated the significant association of PAH exposure with slower processing speed. In addition, measures of postnatal PAH exposure correlated with white matter surface measures in dorsal prefrontal regions bilaterally when controlling for prenatal PAH.
  
  
  CONCLUSIONS
  Our findings suggest that prenatal exposure to PAH air pollutants contributes to slower processing speed, attention-deficit/hyperactivity disorder symptoms, and externalizing problems in urban youth by disrupting the development of left hemisphere white matter, whereas postnatal PAH exposure contributes to additional disturbances in the development of white matter in dorsal prefrontal regions.
authors: Institute for the Developing Mind, Children's Hospital Los Angeles, Los Angeles, California2Keck School of Medicine, University of Southern California, Los Angeles.
authors: Bradley S
authors: BS
authors: Peterson
authors: Heilbrunn Department of Population and Family Health, Mailman School of Public Health, Columbia University, New York, New York4Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, New York, New York.
authors: Virginia A
authors: VA
authors: Rauh
authors: Institute for the Developing Mind, Children's Hospital Los Angeles, Los Angeles, California2Keck School of Medicine, University of Southern California, Los Angeles.
authors: Ravi
authors: R
authors: Bansal
authors: Department of Psychiatry, Columbia College of Physicians and Surgeons, New York, New York6New York State Psychiatric Institute, New York.
authors: Xuejun
authors: X
authors: Hao
authors: Department of Psychiatry, Columbia College of Physicians and Surgeons, New York, New York6New York State Psychiatric Institute, New York.
authors: Zachary
authors: Z
authors: Toth
authors: Institute for the Developing Mind, Children's Hospital Los Angeles, Los Angeles, California2Keck School of Medicine, University of Southern California, Los Angeles.
authors: Giancarlo
authors: G
authors: Nati
authors: Department of Psychiatry, Columbia College of Physicians and Surgeons, New York, New York6New York State Psychiatric Institute, New York.
authors: Kirwan
authors: K
authors: Walsh
authors: Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, New York, New York7Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, Columbia College of Physicians and Surgeons, N.
authors: Rachel L
authors: RL
authors: Miller
authors: Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, New York, New York.
authors: Franchesca
authors: F
authors: Arias
authors: Department of Psychiatry, Columbia College of Physicians and Surgeons, New York, New York6New York State Psychiatric Institute, New York.
authors: David
authors: D
authors: Semanek
authors: Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, New York, New York.
authors: Frederica
authors: F
authors: Perera
mesh_terms: D000328:Adult; D001741:Black or African American; D000393:Air Pollutants / Q000506:poisoning*; D001284:Atrophy; D001921:Brain / Q000187:drug effects* / Q000254:growth & development* / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D003072:Cognition Disorders / Q000139:chemically induced* / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D005260:Female; D006630:Hispanic or Latino; D006801:Humans; D007361:Intelligence Tests; D008279:Magnetic Resonance Imaging; D008297:Male; D059906:Neuroimaging; D011084:Polycyclic Aromatic Hydrocarbons / Q000506:poisoning*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000139:chemically induced / Q000473:pathology / Q000523:psychology*; D066127:White Matter / Q000187:drug effects / Q000473:pathology*
chemical_list: D000393:Air Pollutants; D011084:Polycyclic Aromatic Hydrocarbons