title: Prenatal DDT and DDE exposure and child IQ in the CHAMACOS cohort.
abstract: Although banned in most countries, dichlorodiphenyl-trichloroethane (DDT) continues to be used for vector control in some malaria endemic areas. Previous findings from the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) cohort study found increased prenatal levels of DDT and its breakdown product dichlorodiphenyl-dichloroethylene (DDE) to be associated with altered neurodevelopment in children at 1 and 2years of age. In this study, we combined the measured maternal DDT/E concentrations during pregnancy obtained for the prospective birth cohort with predicted prenatal DDT and DDE levels estimated for a retrospective birth cohort. Using generalized estimating equation (GEE) and linear regression models, we evaluated the relationship of prenatal maternal DDT and DDE serum concentrations with children's cognition at ages 7 and 10.5years as assessed using the Full Scale Intelligence Quotient (IQ) and 4 subtest scores (Working Memory, Perceptual Reasoning, Verbal Comprehension, and Processing Speed) of the Wechsler Intelligence Scale for Children (WISC). In GEE analyses incorporating both age 7 and 10.5 scores (n=619), we found prenatal DDT and DDE levels were not associated with Full Scale IQ or any of the WISC subscales (p-value>0.05). In linear regression analyses assessing each time point separately, prenatal DDT levels were inversely associated with Processing Speed at age 7years (n=316), but prenatal DDT and DDE levels were not associated with Full Scale IQ or any of the WISC subscales at age 10.5years (n=595). We found evidence for effect modification by sex. In girls, but not boys, prenatal DDE levels were inversely associated with Full Scale IQ and Processing Speed at age 7years. We conclude that prenatal DDT levels may be associated with delayed Processing Speed in children at age 7years and the relationship between prenatal DDE levels and children's cognitive development may be modified by sex, with girls being more adversely affected.
authors.affiliation: Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California at Berkeley, Berkeley, CA, USA.
authors.forename: Fraser W
authors.initials: FW
authors.lastname: Gaspar
authors.affiliation: Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California at Berkeley, Berkeley, CA, USA.
authors.forename: Kim G
authors.initials: KG
authors.lastname: Harley
authors.affiliation: Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California at Berkeley, Berkeley, CA, USA.
authors.forename: Katherine
authors.initials: K
authors.lastname: Kogut
authors.affiliation: Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC, Canada.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Chevrier
authors.affiliation: Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California at Berkeley, Berkeley, CA, USA; Central American Institute for Studies on Toxic Substances (IRET), Universidad Nacional, Heredia, Costa Rica.
authors.forename: Ana Maria
authors.initials: AM
authors.lastname: Mora
authors.affiliation: Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: Andreas
authors.initials: A
authors.lastname: Sjödin
authors.affiliation: Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California at Berkeley, Berkeley, CA, USA. Electronic address: eskenazi@berkeley.edu.
authors.forename: Brenda
authors.initials: B
authors.lastname: Eskenazi
mesh_terms: D002140:California; D002648:Child; D002657:Child Development / Q000187:drug effects*; D003071:Cognition / Q000187:drug effects*; D015331:Cohort Studies; D003634:DDT / Q000097:blood / Q000633:toxicity*; D003633:Dichlorodiphenyl Dichloroethylene / Q000097:blood / Q000633:toxicity*; D005260:Female; D006801:Humans; D007361:Intelligence Tests; D008297:Male; D018811:Maternal Exposure / Q000009:adverse effects; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000097:blood / Q000139:chemically induced* / Q000523:psychology; D011446:Prospective Studies; D012189:Retrospective Studies
chemical_list: D003633:Dichlorodiphenyl Dichloroethylene; D003634:DDT
keywords: Back-extrapolation; Children's health; Cognitive development; Environmental exposures; Persistent organic pollutants