Principal Investigator: Matt Keifer, MD, MPH
Adjunct Professor, Env. and Occ. Health Sciences
University of Washington
In 2004, the Washington State Department of Labor and Industries (WADL&I), under mandate from the Washington State Supreme Court, initiated a new cholinesterase (ChE) monitoring program for agricultural workers who handle toxicity class I or II organophosphate (OP) or N-methyl-carbamate (CB) pesticides. Although these investigations have revealed several potential risk factors, none of these factors have been confirmed through a comparison against work practices and conditions among a reference group of handlers who did not have depressed ChE activity. These characteristics of the newly established ChE monitoring program offer researchers an unprecedented opportunity to investigate determinants of overexposure to OP and CB pesticides. In this study, we identified and characterized risk factors for ChE depression among handlers participating in the Washington State ChE monitoring program.
In collaboration with local occupational medicine clinics in rural regions, 265 agricultural pesticide handlers were enrolled in this study. For each participant, the risk of ChE depression was evaluated with respect to workplace, behavioral, and genetic characteristics (paraoxonase or PON1 status). Findings identified the following risk factors being associated with BuChE inhibition: cleaning spray equipment, mixing/loading pesticides and not using a locker to store PPE. Protective factors were: wearing a full-face respirator and wearing chemical-resistant footwear. Identification of genetic susceptibility (PON1 status) in farm workers exposed to organophosphate pesticides. This is the first time that a study of a working population has demonstrated the validity of the assumptions behind PON1’s effect on pesticide overexposure susceptibility.
In 2009, the Committee on Pesticide Exposure Reduction (COPER) was founded to bring together representatives from the three state agencies with responsibilities related to occupational exposure to agricultural pesticides including the WA State Department of Agriculture, WA State Department of Health, WA State Department of Labor and Industries, and the PNASH Center.
Cholinesterase Inhibition | Buena Salud La Inhibicion del Colinesteraza
Good Fruit Grower, March 2009
Hofmann, J. N., Keifer, M. C., De Roos, A. J., Fenske, R. A., Furlong, C. E., van Belle, G., & Checkoway, H. Occupational determinants of serum cholinesterase inhibition among organophosphate-exposed agricultural pesticide handlers in Washington State. Occupational and Environmental Medicine. 2011 June 1;67(6), 375–386. http://doi.org/10.1136/oem.2009.046391. PubMedPMID: 19819864; PMCID: PMC2908529.
Hofmann, J. N., Keifer, M. C., Checkoway, H., De Roos, A. J., Farin, F. M., Fenske, R. A., and Furlong, C. E. Biomarkers of Sensitivity and Exposure in Washington State Pesticide Handlers. Advances in Experimental Medicine and Biology. 2011 Feb 18;660, 19–27. http://doi.org/10.1007/978-1-60761-350-3_3. PubMedPMID: 20221867; PMCID: PMC3041670.
Hofmann-JN, Checkoway-H, Borges-O, Servin-F, Fenske-RA, Keifer-MC. Development of a computer-based survey instrument for Organophospohate and N-methyl-carbamate exposure assessment among agricultural pesticide handlers. Ann. Occup. Hyg. epub April 2010; Vol 54, No 6: 640-50. PubMedPMID: 20413416; PMC2918489.
Hofmann, J. N., Keifer, M. C., Furlong, C. E., De Roos, A. J., Farin, F. M., Fenske, R. A., Checkoway, H. Serum Cholinesterase Inhibition in Relation to Paraoxonase-1 (PON1) Status among Organophosphate-Exposed Agricultural Pesticide Handlers. Environmental Health Perspectives. 2009 June 9;117(9), 1402–1408. http://doi.org/10.1289/ehp.0900682. PubMedPMID: 19750105; PMCID: PMC2737017.