Risk Factor Profile in Parkinson's Disease Subtype with REM Sleep Behavior Disorder

Abstract

Background: Numerous large-scale studies have found diverse risk factors for Parkinson's disease (PD), including caffeine non-use, non-smoking, head injury, pesticide exposure, and family history. These studies assessed risk factors for PD overall; however, PD is a heterogeneous condition. One of the strongest identifiers of prognosis and disease subtype is the cooccurrence of rapid eye movement sleep behavior disorder (RBD). In previous studies, idiopathic RBD was associated with a different risk factor profile from PD and dementia with Lewy bodies, suggesting that the PD-RBD subtype may also have a different risk factor profile. Objective: To define risk factors for PD in patients with or without associated RBD. Methods: In a questionnaire, we assessed risk factors for PD, including demographic, medical, environmental, and lifestyle variables of 189 PD patients with or without associated polysomnography-confirmed RBD. The risk profile of patients with vs. without RBD was assessed with logistic regression, adjusting for age, sex, and disease duration. Results: PD-RBD patients were more likely to have been a welder (OR = 3.11 (1.05-9.223), and to have been regular smokers (OR = 1.96 (1.04-3.68)). There were no differences in use of caffeine or alcohol, other occupations, pesticide exposure, rural living, or well water use. Patients with RBD had a higher prevalence of the combined family history of both dementia and parkinsonism (13.3% vs. 5.5%, OR= 3.28 (1.07-10.0). Conclusion: The RBD-specific subtype of PD may also have a different risk factor profile.