title: Cholinesterase depression and its association with pesticide exposure across the agricultural season among Latino farmworkers in North Carolina.
abstract: BACKGROUND
  Farmworkers can be exposed to a wide variety of pesticides. Assessing cholinesterase activity over time can be used to monitor exposure to organophosphorus and carbamate pesticides.
  
  
  OBJECTIVE
  The goal of this study was to document patterns and variation in cholinesterase levels across the agricultural season (May-August) among field-workers, and to explore the association of cholinesterase depression with pesticide exposure across the agricultural season.
  
  
  METHODS
  Dried blood samples collected from 231 migrant farmworkers sampled from camps in eastern North Carolina up to four times across a summer agricultural season were analyzed for cholinesterase activity, and urine samples were analyzed for metabolites of organophosphorus and carbamate pesticides. Reductions of >or= 15% from an individual's highest value were identified and considered evidence of meaningful cholinesterase activity depression.
  
  
  RESULTS
  The average cholinesterase activity levels were lowest in June, with significantly higher mean values in July and August. When adjusted for age, sex, minutes waited to shower, and days worked in the fields, the number of organophosphorus and carbamate pesticides detected in urine predicted reductions in cholinesterase activity.
  
  
  CONCLUSIONS
  These data demonstrate that workers are experiencing pesticide exposure. Greater enforcement of existing safety regulations or strengthening of these regulations may be warranted. This study demonstrates that serial measurements of cholinesterase activity across an agricultural season can detect exposure to pesticides among field-workers.
authors.affiliation: Department of Epidemiology and Prevention, Division of Public Health Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157 , USA. squandt@wfubmc.edu
authors.forename: Sara A
authors.initials: SA
authors.lastname: Quandt
authors.forename: Haiying
authors.initials: H
authors.lastname: Chen
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Grzywacz
authors.forename: Quirina M
authors.initials: QM
authors.lastname: Vallejos
authors.forename: Leonardo
authors.initials: L
authors.lastname: Galvan
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Arcury
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000383:Agriculture; D002802:Cholinesterases / Q000097:blood*; D005260:Female; D006630:Hispanic or Latino; D006801:Humans; D008297:Male; D008875:Middle Aged; D009657:North Carolina; D016273:Occupational Exposure; D016272:Occupational Health; D010575:Pesticides / Q000009:adverse effects*; D012621:Seasons; D055815:Young Adult
chemical_list: D010575:Pesticides; D002802:Cholinesterases