Change in Cholinesterase Levels and Self-Reported Symptoms Over Two Years

Abstract

In a continuing effort to explore the application and the reliability of self-reported symptoms and cholinesterase levels over time, 22 ginseng producers in central Wisconsin participated in two years of on-site testing. Each year, the participants reported on farming practices and health-seeking behavior and completed a 20-item questionnaire related to possible farm chemical exposure symptoms. Plasma and red cell cholinesterase were measured at the same time. No participant noted seizure symptoms. Of the remaining 19 symptoms, the highest yearly correlations were the following: Have your relatives noted that you have trouble remembering (r = 0.82); have you had trouble falling asleep (r = 0.80); and are your fingers numb (r = 0.81). There were no significant changes in farming practices or health-seeking behavior. In 1994, 14 producers applied their own pesticides; nine did in 1995. Only nine (40.9%) of the participants were under a physician's care and three (13.6%) were under chiropractic care. 152In addition to the initial cholinesterase levels, a second set of cholinesterase levels was obtained in midseason. The initial (Time 1) plasma (r = 0.84) and red cell (r = 0.49) cholinesterase levels were correlated from 1994 to 1995. At follow-up (Time 2), the plasma (r = 0.90) and red cell (r = 0.68) cholinesterase levels remain correlated. The year to year change in plasma cholinesterase levels was significantly related to the change in symptoms for seven of the 19 items. The greatest correlations were for symptoms related to the following: Loss of muscle strength (r = - 0.68); trouble with balance (r = - 0.64); and complaining of finger numbness (r = - 0.56). Only one of the significant correlations with change in plasma level was positive. No change in symptoms was statistically correlated with the change in red cell cholinesterase levels. The significant negative correlations indicate that a decrease in plasma cholinesterase levels was correlated with increased symptoms. Although symptoms may be influenced by many factors, this study does suggest that the change in neuropsychological symptoms is frequently related to the change in plasma cholinesterase. [Article copies available for a fee from The Haworth Document Delivery Service: 1-800-342-9678. E-mail address: getinfo@haworth.com]