title: Blood acetylcholinesterase and butyrylcholinesterase as biomarkers of cholinesterase depression among pesticide handlers.
abstract: OBJECTIVE
  Agricultural pesticide handlers are at an elevated risk for overexposure to organophosphate (OP) pesticides, but symptoms can be difficult to recognise, making biomarkers invaluable for diagnosis. Occupational monitoring programmes for cholinesterase depression generally rely on measuring activity of either of the two common blood cholinesterases which serve as proxy measurements for nervous-system acetylcholinesterase activity: red blood cell acetylcholinesterase (AChE) and plasma butyrylcholinesterase (BChE). These biomarkers, however, may be affected differentially by some OPs and the relationship between them has not been well characterised. We aim to determine the association between blood AChE and BChE activity levels and assess whether they produce comparable classifications of clinical cholinesterase depression among OP pesticide handlers.
  
  
  METHODS
  Using blood samples from 215 participants of the Washington State Cholinesterase Monitoring Program, we quantified changes in AChE and BChE activity from before and after exposure to OP pesticides and calculated Pearson correlation statistics for correlation of AChE and BChE changes in activity, as well as weighted κ statistics for agreement of classification of clinical cholinesterase depression based on AChE versus BChE measurements.
  
  
  RESULTS
  AChE and BChE activity measurements are weakly negatively correlated in our study population. Reaching a clinical threshold for diagnosis of cholinesterase depression based on the AChE marker did not correlate with reaching clinical depression based on the BChE marker.
  
  
  CONCLUSIONS
  Both AChE and BChE should be measured in monitoring programmes because they may both give potentially important but disparate classifications of clinical cholinesterase depression.
authors.affiliation: Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
authors.forename: Jean
authors.initials: J
authors.lastname: Strelitz
authors.affiliation: Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
authors.forename: Lawrence S
authors.initials: LS
authors.lastname: Engel
authors.affiliation: National Farm Medicine Center, Marshfield Clinic Research Foundation, Marshfield, Wisconsin, USA.
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Keifer
mesh_terms: D000110:Acetylcholinesterase / Q000097:blood*; D000293:Adolescent; D000328:Adult; D000383:Agriculture; D015415:Biomarkers / Q000097:blood; D002091:Butyrylcholinesterase / Q000097:blood*; D002800:Cholinesterase Inhibitors / Q000009:adverse effects; D003863:Depression / Q000097:blood* / Q000139:chemically induced; D003866:Depressive Disorder / Q000097:blood* / Q000139:chemically induced; D005260:Female; D006801:Humans; D007306:Insecticides / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000097:blood* / Q000139:chemically induced / Q000523:psychology; D016273:Occupational Exposure / Q000009:adverse effects; D009943:Organophosphorus Compounds / Q000009:adverse effects*; D014861:Washington; D055815:Young Adult
chemical_list: D015415:Biomarkers; D002800:Cholinesterase Inhibitors; D007306:Insecticides; D009943:Organophosphorus Compounds; D000110:Acetylcholinesterase; D002091:Butyrylcholinesterase