Organic solvent exposure and neuropsychological function among fishers in North Carolina

Commercial fishers work with a variety of organic solvents that are toxic to the central nervous system including fuel and styrene. The goal of my research was to characterize fishers' occupational exposure to these solvents and determine the effect of exposure on neuropsychological function. The study population consisted of 238 fishers and other workers from North Carolina who were recruited to participate in an ongoing longitudinal cohort study. Participants were followed for approximately 2.5 years.; Three studies were conducted. First, a self-monitoring approach was used to obtain repeat measurements of personal exposure to benzene in fuel emissions among a subgroup of fishers (n = 50). Predicted exposure levels were determined for categories of engine type using mixed-effect linear regression models. Second, weekly or biweekly telephone interviews (n = 13,028) containing self-reported descriptions of maintenance work, as well as self-reports of symptoms were analyzed to estimate crude and adjusted rate ratios using Poisson regression methods. Finally, the effect of cumulative and recent maintenance work on neuropsychological test performance was estimated using Generalized Estimating Equations (GEEs). The data for these analyses included 723 neuropsychological examinations among 219 fishers.; Personal exposure to fishers on boats equipped with 2-stroke, 4-stroke, and diesel engines were estimated to be 50.1, 32.6 and 27.9 μg/m 3, respectively. Fishers reported higher rates of symptoms indicative of cognitive effects in weeks they did maintenance work involving solvents compared to weeks they did not. However, no strong or consistent relationship between self-reported exposure to solvents during maintenance work and objective neuropsychological performance was observed.; Exposure to neurotoxic organic solvents was documented in this population. The conflicting results regarding the effect of maintenance work on neuropsychological symptoms versus neuropsychological test outcomes may be explained by variety of factors. Neuropsychological testing may not be adequately sensitive to measure the subtle effects of solvents. Alternatively, the exposure levels may not have been high enough to affect the central nervous system. If this is the case, the associations between maintenance work and self-reported symptoms may have been biased. However, it is also possible that exposure misclassification resulted in attenuation of the associations between maintenance work and neuropsychological test performance.