NEUROTOXICITY AMONG PESTICIDE APPLICATORS EXPOSED TO ORGANOPHOSPHATES

Objectives-An epidemiological study of 90 male pesticide applicators l icensed in New York was conducted to investigate the effect of exposur e to organophosphate pesticides on the peripheral nervous system. Meth ods-A cohort of farmers and pesticide applicators from New York State were questioned off season (November 1988-February 1989) and again dur ing the spraying season (April 1989-August 1989) about the presence of several acute signs and symptoms. Short term exposure was validated b y measuring the concentration of dimethylthiophosphate (DMTP), a metab olite of guthion, in urine. Chronic signs of subtle peripheral nerve d amage were determined by vibration threshold sensitivity of the farmer s and applicators tested during November 1988-February 1989 and compar ed with controls drawn from the general population who were tested dur ing the same time period the next year (November 1989-February 1990). Vibration threshold sensitivity was determined for both the hands and feet. Long term exposure to pesticides was determined by questionnaire . Results-Paired t tests show that mean vibration threshold scores wer e significantly higher for the dominant (P < 0.00) and non-dominant (P < 0.04) hands among pesticide applicators when compared with scores f or population based controls individually matched on age, sex, and cou nty of residence. Conclusions-A significant increase in mean vibration threshold sensitivity for the dominant and non-dominant hand suggests previous organophosphate exposure among pesticide applicators was ass ociated with a loss of peripheral nerve function.