title: Acetylcholinesterase activity and neurodevelopment in boys and girls.
abstract: BACKGROUND
  Organophosphate exposures can affect children's neurodevelopment, possibly due to neurotoxicity induced by acetylcholinesterase (AChE) inhibition, and may affect boys more than girls. We tested the hypothesis that lower AChE activity is associated with lower neurobehavioral development among children living in Ecuadorian floricultural communities.
  
  
  METHODS
  In 2008, we examined 307 children (age: 4-9 years; 52% male) and quantified AChE activity and neurodevelopment in 5 domains: attention/executive functioning, language, memory/learning, visuospatial processing, and sensorimotor (NEPSY-II test). Associations were adjusted for demographic and socioeconomic characteristics and height-for-age, flower worker cohabitation, and hemoglobin concentration.
  
  
  RESULTS
  Mean ± standard deviation AChE activity was 3.14 ± 0.49 U/mL (similar for both genders). The range of scores among neurodevelopment subtests was 5.9 to 10.7 U (standard deviation: 2.6-4.9 U). Girls had a greater mean attention/executive functioning domain score than boys. In boys only, there were increased odds ratios of low (<9th percentile) neurodevelopment among those in the lowest tertile versus the highest tertile of AChE activity (odds ratios: total neurodevelopment: 5.14 [95% confidence interval (CI): 0.84 to 31.48]; attention/executive functioning domain: 4.55 [95% CI: 1.19 to 17.38], memory/learning domain: 6.03 [95% CI: 1.17 to 31.05]) after adjustment for socioeconomic and demographic factors, height-for-age, and hemoglobin. Within these domains, attention, inhibition and long-term memory subtests were most affected.
  
  
  CONCLUSIONS
  Low AChE activity was associated with deficits in neurodevelopment, particularly in attention, inhibition, and memory in boys but not in girls. These critical cognitive skills affect learning and academic performance. Added precautions regarding secondary occupational pesticide exposure would be prudent.
authors.affiliation: Division of Global Health, Department of Family and Preventive Medicine, University of California-San Diego, 9500 Gilman Dr M/C 0725, La Jolla, CA 92093-0725. jrsuarez@ucsd.edu.
authors.forename: Jose R
authors.initials: JR
authors.lastname: Suarez-Lopez
authors.forename: John H
authors.initials: JH
authors.lastname: Himes
authors.forename: David R
authors.initials: DR
authors.lastname: Jacobs
authors.forename: Bruce H
authors.initials: BH
authors.lastname: Alexander
authors.forename: Megan R
authors.initials: MR
authors.lastname: Gunnar
mesh_terms: D000110:Acetylcholinesterase / Q000097:blood*; D000383:Agriculture; D001288:Attention / Q000187:drug effects / Q000502:physiology; D015415:Biomarkers / Q000097:blood; D002648:Child; D002657:Child Development / Q000187:drug effects* / Q000502:physiology; D002675:Child, Preschool; D002800:Cholinesterase Inhibitors / Q000633:toxicity*; D003430:Cross-Sectional Studies; D004484:Ecuador; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D035264:Flowers; D006306:Health Surveys; D006801:Humans; D007266:Inhibition, Psychological; D007306:Insecticides / Q000633:toxicity*; D016014:Linear Models; D008297:Male; D008568:Memory / Q000187:drug effects / Q000502:physiology; D009483:Neuropsychological Tests; D010755:Organophosphates / Q000633:toxicity*; D012737:Sex Factors
chemical_list: D015415:Biomarkers; D002800:Cholinesterase Inhibitors; D007306:Insecticides; D010755:Organophosphates; D000110:Acetylcholinesterase
keywords: AChE; ADD; ADHD; Ecuador; acetylcholinesterase; agricultural communities; agriculture; attention; boys; children; floriculture; flower; girls; growth; inhibition; inhibitory control; memory; neurobehavioral development; neurodevelopment; pesticide; plantation