Prodromal Parkinson's disease and subsequent risk of Parkinson's disease and mortality.

Association of prodromal Parkinson's disease (PD) with risk of PD and risk of mortality in individuals with PD warrant investigation through large-scale prospective study. We included 501,475 participants without PD at baseline. Eight prodromal features were measured. Incident PD cases were identified via hospital admission, death register, and self-report. Cox regression models were used to compute hazard ratios (HRs) and 95% confidence intervals (CIs). Multivariable-adjusted HRs and 95%CIs were 3.12 (2.58-3.78) for men and 2.71 (2.11-3.47) for women. Prodromal PD predicted only PD onset occurred during the first 6 years of follow-up (HR = 10.5; 95% CI: 8.60-12.9), but not after 6 years (HR = 1.00; 95%CI: 0.76-1.32). The presence of prodromal PD conferred a higher risk of mortality among participants with PD. Having prodromal PD were associated with higher probability of developing PD in short-term and higher risk of mortality among individuals with PD.