Is impaired olfactory function an early warning sign for health effects of pesticide exposure in Latino farmworkers?

Farmworkers are at risk for health consequences of pesticide exposure. While acute exposure causes immediate symptoms, most exposure is likely low level and chronic, with possible health effects manifest years later as neurodegenerative diseases. We hypothesized that subclinical effects might be detected in current farmworkers to provide evidence of early stage neurodegeneration. From animal studies, olfactory function, an early sign of Parkinson's disease, is known to be sensitive to pesticide exposure. The study objective was to compare olfactory function in comparable samples of exposed and non-exposed workers. Migrant farmworkers (n=304) and a comparison sample of non-farmworkers (n=247) 18+ years and self-identified Latino/Hispanic were recruited in North Carolina with the help of community partners. Non-farmworkers were restricted to those with no occupational pesticide exposure in the previous 3 years. Odor identification and odor threshold tests were administered in a clinic setting and analyzed using logistic and linear regressions, adjusting for age, gender, and smoking. Lifetime pesticide exposure was obtained using the NINDS common data elements questionnaire to confirm group pesticide exposure differences. The total sample was 84% male, 23% current smokers, and 97% born in Latin America. Farmworkers and non-farmworkers did not differ in odor identification performance (p=0.6726). However, non-farmworkers detected a standard odor at significantly lower concentrations than did farmworkers (p<.0001). Farmworkers display significant non-selective impairment in olfactory function, compared to non-farmworkers. These results suggest that subclinical markers signal neurological effects before neurodegenerative diseases can be detected. Such data could be important in demonstrating health consequences of occupational pesticide exposure.