A case-referent study of extrapyramidal signs (preparkinsonism) in rural communities of Israel

Background: In previous studies we reported an increased prevalence of Parkinson's disease in several kibbutzim of Southern Israel (cluster kibbutzim). Subsequent studies revealed a significant prevalence of subjects presenting extrapyramidal signs (preparkinsonism) in the same kibbutzim. On follow-up worsening of these signs was observed in some of the older subjects, some of them actually being diagnosed as suffering from 1-Dopa responsive Parkinson's disease. The current study was designed to evaluate possible etiologic factors for the development of preparkinsonism. Methods: 317 subjects over the age of 40, living in five kibbutzim were examined and interviewed. 95 subjects presenting extrapyramidal signs were compared with 95 control subjects. They were matched for age, sex and length of residence in the kibbutz. Odds ratios were computed to identify exposure variables for logistic regression analyses. Detectors for carbamates and organic phosphates were applied at different sites of these kibbutzim. Results: The severity and frequency of the extrapyramidal signs were higher in the older age groups, more in the "cluster", than in other kibbutzim. A very strong association was found between field crop work exposure, particularly cotton, and preparkinsonism (p = 0.0007) and a slightly weaker association for landscape work. The detectors picked up abundant pesticide traces (carbamates and organic phosphates) in the residential areas fairly distant from sites of aerial spray. Conclusions: We assume a chronic passive exposure of the residents in these kibbutzim to pesticides, in addition to any occupational exposures.