Comparison of plasma cholinesterase depression among workers occupationally exposed to organophosphorus pesticides as reported by various studies.

A number of studies have reported on the inhibitory effects of organophosphorus pesticides (OPs) on the enzyme cholinesterase (ChE) among agricultural workers. With the increasing use of OPs, surveys of blood ChE activity on exposed workers may help to identify workers at greatest risk and to provide insight into the use history--e.g., mixing, loading, application, and harvesting--that might lead to a hazardous situation. Although it does appear that measurements of ChE activity are valuable in worker surveillance programs, it is difficult to interpret findings from various studies since they are dependent on the method of assay and the emphasis is usually placed on statistical tests (i.e., p values) that depend on the number of subjects studied. In the present paper a method is presented to compare ChE values reported in several studies utilizing various methods and units of measurement, and to assess the impact of OP exposure as a percentage of subjects with ChE values depressed below normal limits.