Non-motor features of Parkinson’s disease in a nested case–control study of US men

Several non-motor features may individually contribute to identify prodromal Parkinson's disease (PD), but little is known on how they interact.We conducted a case-control study nested within the Health Professionals Follow-up Study in a large cohort of men age 40-75 at recruitment in 1986. Cases (n=120) had confirmed PD, were<85 in January 2012, returned a 2012 questionnaire with questions on probable rapid eye movement sleep behaviour disorder...