title: Determinants of butyrylcholinesterase inhibition among agricultural pesticide handlers in Washington State: an update.
abstract: OBJECTIVE
  Organophosphate (OP) and N-methyl-carbamate (CB) insecticides are used widely in agriculture to manage insect pests of economic importance. Agricultural workers are more likely to suffer exposure because of the widespread use of OP/CBs in agriculture, and pesticide-related illnesses among handlers may be more severe when compared to other farm workers. The goal of this study was to identify occupational and personal characteristics associated with butyrylcholinesterase (BuChE) inhibition in participants recruited from the Washington State Cholinesterase Monitoring Program from 2006 to 2011.
  
  
  METHODS
  We conducted a longitudinal study among agricultural pesticide handlers in Washington State during the OP/CB spray season (March-July) over a 6-year period (2006-2011). Linear mixed effects regression models were used to evaluate BuChE inhibition in relation to self-reported occupational and personal characteristics.
  
  
  RESULTS
  Relative to pre-season baseline levels, the mean decrease in BuChE activity during the OP/CB spray season over all years of the study period was 3.77% (P < 0.001). Greater BuChE inhibition was observed among handlers who reported using multiple OP/CBs (β = -2.70, P = 0.045), mixed or loaded OP/CBs (β = -3.97, P = 0.002), did not store personal protective equipment (PPE) in a locker at work (β = -3.4, P = 0.014), or did not wear chemical-resistant boots (β = -16.6, P < 0.001).
  
  
  CONCLUSIONS
  The Washington State Cholinesterase Monitoring Program has provided a valuable opportunity to evaluate potential sources of OP/CB exposure among agricultural pesticide handlers. Several previously reported associations were confirmed in the current analysis, which included a larger number of pesticide handlers enrolled over a longer time period. The use of multiple OP/CBs and mixing/loading activities were significant risk factors, and the use of chemical-resistant boots and lockers for PPE storage were protective factors. Our findings point toward logical interventions to reduce exposure such as the implementation of engineering controls for mixing/loading activities, requirements for appropriate footwear, and the regular use of lockers for PPE storage.
authors.affiliation: 1.Department of Environmental and Occupational Health Sciences, University of Washington, Box 357234, Seattle, WA 98195-7234, USA.
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Krenz
authors.affiliation: 2.Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD 20892, USA.
authors.forename: Jonathan N
authors.initials: JN
authors.lastname: Hofmann
authors.affiliation: 3.Department of Statistics, University of Washington, Seattle, WA, 98195-4322 USA.
authors.forename: Theresa R
authors.initials: TR
authors.lastname: Smith
authors.affiliation: 1.Department of Environmental and Occupational Health Sciences, University of Washington, Box 357234, Seattle, WA 98195-7234, USA.
authors.forename: Rad N
authors.initials: RN
authors.lastname: Cunningham
authors.affiliation: 1.Department of Environmental and Occupational Health Sciences, University of Washington, Box 357234, Seattle, WA 98195-7234, USA.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Fenske
authors.affiliation: 1.Department of Environmental and Occupational Health Sciences, University of Washington, Box 357234, Seattle, WA 98195-7234, USA simpson1@uw.edu.
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Simpson
authors.affiliation: 4.National Farm Medicine Center, Marshfield Clinic Research Foundation, Marshfield, WI, 54449 USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Keifer
mesh_terms: D000293:Adolescent; D000328:Adult; D000382:Agricultural Workers' Diseases / Q000097:blood*; D000383:Agriculture; D000465:Algorithms; D002091:Butyrylcholinesterase / Q000633:toxicity*; D002219:Carbamates / Q000032:analysis; D002800:Cholinesterase Inhibitors / Q000097:blood*; D006801:Humans; D007306:Insecticides / Q000633:toxicity; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000517:prevention & control; D010755:Organophosphates / Q000032:analysis; D010575:Pesticides / Q000633:toxicity*; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D014861:Washington; D055815:Young Adult
chemical_list: D002219:Carbamates; D002800:Cholinesterase Inhibitors; D007306:Insecticides; D010755:Organophosphates; D010575:Pesticides; C020401:N-methylcarbamate; D002091:Butyrylcholinesterase
keywords: agriculture; biological monitoring; cholinesterase; determinants of exposure; occupational exposure; organophosphorus compounds; pesticide; pesticide handler