Risk factors for cholinesterase inhibition among agricultural pesticide handlers in Washington State

Organophosphate (OP) insecticides are widely used in agriculture in the United States and abroad. Over-exposure to OPs can inhibit cholinesterase (ChE) enzyme activity, which plays a critical role in regulating transmission of nerve signals in the body. In 2004, the Washington State Department of Labor and Industries (L&I) initiated a new ChE monitoring program for agricultural workers who handle OPs. Washington is only the second state in the U.S. to establish a ChE monitoring program. During the 2006 and 2007 spray seasons, we recruited agricultural pesticide handlers in the ChE monitoring program for a cross-sectional study evaluating potential risk factors for ChE inhibition. A total of 154 study participants completed a computer-based survey about workplace practices and conditions, including: 1) pesticide handling activities performed and spray equipment used; 2) crops treated and pesticides applied; 3) duration and frequency of handling activities; 4) use, condition, and storage of personal protective equipment; 5) use of decontamination facilities; 6) pesticide safety trainings received; 7) non-routine exposures; and 8) acute exposure events. Almost all study participants were Hispanic or Latino (99%), and most were educated in Mexico (90.3%). Results of the survey will be reported in this presentation. We will identify work practices, workplace conditions, and behaviors that may be associated with risk of pesticide over-exposure, as determined by ChE inhibition. Ultimately, we hope to use the results of this study to characterize potential mechanisms of pesticide over-exposure in order to reduce such exposures in the future.