title: Pyrethroid pesticide exposure and parental report of learning disability and attention deficit/hyperactivity disorder in U.S. children: NHANES 1999-2002.
abstract: BACKGROUND
  Use of pyrethroid insecticides has increased dramatically over the past decade; however, data on their potential health effects, particularly on children, are limited.
  
  
  OBJECTIVE
  We examined the cross-sectional association between postnatal pyrethroid exposure and parental report of learning disability (LD) and attention deficit/hyperactivity disorder (ADHD) in children 6-15 years of age.
  
  
  METHODS
  Using logistic regression, we estimated associations of urinary metabolites of pyrethroid insecticides with parent-reported LD, ADHD, and both LD and ADHD in 1,659-1,680 children participating in the National Health and Nutrition Examination Survey (1999-2002).
  
  
  RESULTS
  The prevalence rates of parent-reported LD, ADHD, and both LD and ADHD were 12.7%, 10.0%, and 5.4%, respectively. Metabolite detection frequencies for 3-PBA [3-phenoxybenzoic acid], cis-DCCA [cis-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid], and trans-DCCA [trans-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid] were 77.1%, 35.6%, and 33.9%, respectively. The geometric mean 3-PBA concentration was 0.32 μg/L (median = 0.31 μg/L; interquartile rage = 0.10-0.89 μg/L). cis- and trans-DCCA 75th-percentile concentrations were 0.21 μg/L and 0.68 μg/L, respectively. Log10-transformed 3-PBA concentrations were associated with adjusted odds ratios (ORs) of 1.18 (95% CI: 0.92, 1.51) for parent-reported LD, 1.16 (95% CI: 0.85, 1.58) for ADHD, and 1.45 (95% CI: 0.92, 2.27) for both LD and ADHD. Adjusted ORs remained nonsignificant and decreased after controlling for creatinine and other environmental chemicals previously linked to altered neurodevelopment. Similarly, no significant associations were observed for cis- and trans-DCCA.
  
  
  CONCLUSIONS
  Postnatal pyrethroid exposure was not associated with parental report of LD and/or ADHD. Given the widespread and increasing use of pyrethroids, future research should evaluate exposures at current levels, particularly during critical windows of brain development.
authors.affiliation: Center for Environmental Research and Children's Health, School of Public Health, University of California, Berkeley, Berkeley, California, USA.
authors.forename: Lesliam
authors.initials: L
authors.lastname: Quirós-Alcalá
authors.forename: Suril
authors.initials: S
authors.lastname: Mehta
authors.forename: Brenda
authors.initials: B
authors.lastname: Eskenazi
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000139:chemically induced / Q000453:epidemiology*; D002648:Child; D002662:Child Health Services; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D007306:Insecticides / Q000009:adverse effects*; D007859:Learning Disabilities / Q000139:chemically induced / Q000453:epidemiology*; D016014:Linear Models; D008297:Male; D018811:Maternal Exposure; D009749:Nutrition Surveys; D026023:Permethrin / Q000009:adverse effects*; D011247:Pregnancy; D015995:Prevalence; D014481:United States / Q000453:epidemiology
chemical_list: D007306:Insecticides; D026023:Permethrin