A NEUROLOGICAL DISEASE CLUSTER AT A MANUFACTURING PLANT

A case-control study was conducted an at automotive carburetor plant t o investigate exposures associated with a cluster of cases exhibiting neurological symptoms that resembled multiple sclerosis. Eighteen case s were identified with symptom onset between 1970 and 1985. Four contr ols per case were selected randomly from the plant population, and the y were matched by year of birth, gender, and ethnicity. From work hist ories and telephone interviews, cumulative exposures for 10 chemical o r process categories were computed, based on rank estimates of exposur e levels. Mantel-Haenszel procedures and logistic regression modeling produced statistically significant relative risks associated with die- casting and organophosphate exposures, using unweighted and latency-we ighted cumulative exposures. The study was hampered by the inability t o pursue further clinical neurological evaluation of the cases, by the small number of cases, and by uncertainties of exposure assessment. A delayed neuropathy arising from organophosphate exposure in hydraulic and machining fluids is proposed.