Occupational Pesticide Exposure and the Risk of Death in Patients with Parkinson's Disease: an Observational Study in Southern Brazil

Background: Multiple studies have suggested that various pesticides are associated with a higher risk of developing Parkinson's disease (PD) and may influence the progression of the disease. However, the evidence regarding the impact of pesticide exposure on mortality among patients with PD is equivocal. This study examines whether pesticide exposure influences the risk of mortality among patients with PD in Southern Brazil.

Methods: A total of 150 patients with idiopathic PD were enrolled from 2008 to 2013 and followed until 2019. In addition to undergoing a detailed neurologic evaluation, patients completed surveys regarding socioeconomic status and environmental exposures.

Results: Twenty patients (13.3%) reported a history of occupational pesticide exposure with a median duration of exposure of 10 years (mean = 13.1, SD = 11.2). Patients with a history of occupational pesticide exposure had higher UPDRS-III scores, though there were no significant differences in regards to age, sex, disease duration, Charlson Comorbidity Index, and age at symptom onset. Patients with occupational pesticide exposure were more than twice as likely to die than their unexposed PD counterparts (HR = 2.32, 95% CI [1.15, 4.66], p = 0.018). Occupational pesticide exposure was also a significant predictor of death in a cox-proportional hazards model which included smoking and caffeine intake history (HR = 2.23, 95% CI [1.09, 4.59], p = 0.03)) and another which included several measures of socioeconomic status (HR = 3.91, 95% CI [1.32, 11.58], p = 0.01).

Conclusion: In this prospective cohort study, we found an increased all-cause mortality risk in PD patients with occupational exposure to pesticides. More studies are needed to further analyze this topic with longer follow-up periods, more detailed exposure information, and more specific causes of mortality.