title: Prenatal exposure to organophosphate pesticides and IQ in 7-year-old children.
abstract: BACKGROUND
  Organophosphate (OP) pesticides are neurotoxic at high doses. Few studies have examined whether chronic exposure at lower levels could adversely affect children's cognitive development.
  
  
  OBJECTIVE
  We examined associations between prenatal and postnatal exposure to OP pesticides and cognitive abilities in school-age children.
  
  
  METHODS
  We conducted a birth cohort study (Center for the Health Assessment of Mothers and Children of Salinas study) among predominantly Latino farmworker families from an agricultural community in California. We assessed exposure to OP pesticides by measuring dialkyl phosphate (DAP) metabolites in urine collected during pregnancy and from children at 6 months and 1, 2, 3.5, and 5 years of age. We administered the Wechsler Intelligence Scale for Children, 4th edition, to 329 children 7 years of age. Analyses were adjusted for maternal education and intelligence, Home Observation for Measurement of the Environment score, and language of cognitive assessment.
  
  
  RESULTS
  Urinary DAP concentrations measured during the first and second half of pregnancy had similar relations to cognitive scores, so we used the average of concentrations measured during pregnancy in further analyses. Averaged maternal DAP concentrations were associated with poorer scores for Working Memory, Processing Speed, Verbal Comprehension, Perceptual Reasoning, and Full-Scale intelligence quotient (IQ). Children in the highest quintile of maternal DAP concentrations had an average deficit of 7.0 IQ points compared with those in the lowest quintile. However, children's urinary DAP concentrations were not consistently associated with cognitive scores.
  
  
  CONCLUSIONS
  Prenatal but not postnatal urinary DAP concentrations were associated with poorer intellectual development in 7-year-old children. Maternal urinary DAP concentrations in the present study were higher but nonetheless within the range of levels measured in the general U.S. population.
authors.affiliation: University of California-Berkeley, Center for Environmental Research and Children's Health, School of Public Health, Berkeley, California 94704, USA.
authors.forename: Maryse F
authors.initials: MF
authors.lastname: Bouchard
authors.forename: Jonathan
authors.initials: J
authors.lastname: Chevrier
authors.forename: Kim G
authors.initials: KG
authors.lastname: Harley
authors.forename: Katherine
authors.initials: K
authors.lastname: Kogut
authors.forename: Michelle
authors.initials: M
authors.lastname: Vedar
authors.forename: Norma
authors.initials: N
authors.lastname: Calderon
authors.forename: Celina
authors.initials: C
authors.lastname: Trujillo
authors.forename: Caroline
authors.initials: C
authors.lastname: Johnson
authors.forename: Asa
authors.initials: A
authors.lastname: Bradman
authors.forename: Dana Boyd
authors.initials: DB
authors.lastname: Barr
authors.forename: Brenda
authors.initials: B
authors.lastname: Eskenazi
mesh_terms: D002648:Child; D005260:Female; D006801:Humans; D007360:Intelligence / Q000187:drug effects*; D007361:Intelligence Tests; D010755:Organophosphates / Q000633:toxicity* / Q000652:urine; D010575:Pesticides / Q000633:toxicity*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects
chemical_list: D010755:Organophosphates; D010575:Pesticides