High Pesticide Exposure Events and Dream-Enacting Behaviors Among US Farmers.

Background: Dream-enacting behavior is a characteristic feature of rapid eye movement sleep behavior disorder, the most specific prodromal marker of synucleinopathies. Pesticide exposure may be associated with dream-enacting behaviors, but epidemiological evidence is limited.

Objectives: To examine high pesticide exposure events in relation to dream-enacting behaviors among farmers in the Agricultural Health Study.

Methods: We conducted multivariable logistic regression analyses to examine high pesticide exposure events reported from 1993 to 1997 in relation to dream-enacting behaviors assessed from 2013 to 2015 among 11,248 farmers (age 47 ± 11 years).

Results: A history of dream-enacting behaviors was reported by 939 (8.3%) farmers. Compared with farmers who did not report any high pesticide exposure event, those who reported were more likely to endorse dream-enacting behaviors 2 decades later (odds ratio = 1.75; 95% confidence interval [CI], 1.49-2.05). The association appeared stronger when there was a long delay in washing with soap and water after the event (2.63 [95% CI, 1.62-4.27] for waiting >6 hours vs. 1.71 [95% CI, 1.36-2.15] for washing within 30 minutes) and when the exposure involved the respiratory or digestive tract (2.04 [95% CI, 1.62-2.57] vs. 1.58 [95% CI, 1.29-1.93] for dermal contact only). In the analyses of specific pesticides involved, we found positive associations with two organochlorine insecticides (dichlorodiphenyltrichloroethane and lindane), four organophosphate insecticides (phorate, ethoprop, terbufos, and parathion), two herbicides (alachlor and paraquat), and fungicides as a group.

Conclusions: This study provides the first epidemiological evidence that high pesticide exposures may be associated with a higher risk of dream-enacting behaviors. © 2022 International Parkinson and Movement Disorder Society.