Abstract
BACKGROUND: The prevalence ratio (PR) and incidence rate ratio (IRR) of nonmotor symptoms (NMS) were calculated for early Parkinson's disease (PD) versus non-PD from 2 observational studies. METHODS: NMS were assessed through the self-reported Non-Motor Symptom Questionnaire in the online Fox Insight study and through self- and clinician-rated scales in the Parkinson's Progression Marker Initiative (PPMI) study. Age- and sex-adjusted/matched PR and IRR were estimated for each NMS by PD status using Poisson regression. RESULTS: Most NMS occurred more frequently in PD. Among 15,194 Fox Insight participants, sexual dysfunction had the largest adjusted PR (12.4 [95% CI, 6.9-22.2]) and dysgeusia/hyposmia had the largest adjusted IRR over a 2-year median follow-up (17.0 [95% CI, 7.8-37.1]). Among 607 PPMI participants, anosmia had the largest PR (16.6 [95% CI, 6.1-44.8]). During the 7-year median follow-up, hallucinations had the largest IRR (13.5 [95% CI, 6.3-28.8]). CONCLUSION: Although many NMS are more common in early PD than in non-PD, their occurrence may differ with time (hallucinations) or data collection methods (sexual dysfunction).