title: Association of organophosphate pesticide exposure and paraoxonase with birth outcome in Mexican-American women.
abstract: BACKGROUND
  Epidemiologic studies suggest that maternal organophosphorus (OP) pesticide exposure is associated with poorer fetal growth, but findings are inconsistent. We explored whether paraoxonase (PON1), a key enzyme involved in detoxification of OPs, could be an effect modifier in this association.
  
  
  METHODS
  The study population included 470 pregnant women enrolled in the CHAMACOS Study, a longitudinal cohort study of mothers and children living in an agricultural region of California. We analyzed urine samples collected from mothers twice during pregnancy for dialkyl phosphate (DAP) metabolites of OP pesticides. We analyzed maternal and fetal (cord) blood samples for PON1 genotype (PON1(192) and PON1(-108)) and enzyme activity (paraoxonase and arylesterase). Infant birth weight, head circumference, and gestational age were obtained from medical records.
  
  
  RESULTS
  Infants' PON1 genotype and activity were associated with birth outcome, but mothers' were not. Infants with the susceptible PON1(-108TT) genotype had shorter gestational age (β = -0.5 weeks, 95% Confidence Interval (CI): -0.9, 0.0) and smaller head circumference (β = -0.4 cm, 95% CI: -0.7, 0.0) than those with the PON1(-108CC) genotype. Infants' arylesterase and paraoxonase activity were positively associated with gestational age. There was some evidence of effect modification with DAPs: maternal DAP concentrations were associated with shorter gestational age only among infants of the susceptible PON1(-108TT) genotype (p-value(interaction) = 0.09). However, maternal DAP concentrations were associated with larger birth weight (p-value(interaction) = 0.06) and head circumference (p-value(interaction)<0.01) in infants with non-susceptible genotypes.
  
  
  CONCLUSIONS
  Infants whose PON1 genotype and enzyme activity levels suggested that they might be more susceptible to the effects of OP pesticide exposure had decreased fetal growth and length of gestation. PON1 may be another factor contributing to preterm or low birth weight birth.
authors: Center for Environmental Research and Children's Health, School of Public Health, University of California, Berkeley, California, United States of America. kharley@berkeley.edu
authors: Kim G
authors: KG
authors: Harley
authors: Karen
authors: K
authors: Huen
authors: Raul
authors: R
authors: Aguilar Schall
authors: Nina T
authors: NT
authors: Holland
authors: Asa
authors: A
authors: Bradman
authors: Dana Boyd
authors: DB
authors: Barr
authors: Brenda
authors: B
authors: Eskenazi
mesh_terms: D000328:Adult; D043303:Aryldialkylphosphatase / Q000235:genetics*; D005260:Female; D005838:Genotype; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D018811:Maternal Exposure / Q000009:adverse effects*; D017058:Mexican Americans; D009943:Organophosphorus Compounds / Q000633:toxicity* / Q000652:urine; D010575:Pesticides / Q000633:toxicity*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000139:chemically induced; D055815:Young Adult
chemical_list: D009943:Organophosphorus Compounds; D010575:Pesticides; D043303:Aryldialkylphosphatase