Age-Stratified Risk of Dementia in Parkinson's Disease: A Nationwide, Population-Based, Retrospective Cohort Study in Taiwan.

Ting-Ya Chang,Ching-Heng Lin,Ming-Hong Chang,Yi-Huei Chen,Chun-Pai Yang

doi:10.3389/fneur.2021.748096

Abstract

Introduction: Parkinson's disease (PD) manifests with dominant motor symptoms and a wide range of non-motor symptoms (NMS). Dementia is one of the most disabling and exhausting NMS throughout the clinical course. We conducted a population-based, age-stratified, retrospective cohort study to investigate the incidence rate and risk of dementia of patients with newly diagnosed PD, and linked to the clinicopathological PD subtypes.Methods: Patients with newly diagnosed PD (PD group, n = 760) and control subjects (non-PD group, n = 3,034) were selected from the Taiwan's National Health Insurance Research Database from January 2001 to December 2005. The dementia incidence rate and dementia-free survival rate were calculated.Results: The overall dementia incidence rate was 17.5 and 5.7 per 1,000 person-years in PD and non-PD groups, respectively. The PD group had a significantly higher overall risk of dementia than controls (p < 0.001). The younger PD patients had a lower dementia incidence rate than the older PD patients, but a higher dementia risk compared to the same age of controls (<60 years, adjusted HR 6.55, 95% CI 1.56–27.48, p = 0.010). The dementia-free survival rate was significantly lower in the PD group compared to the non-PD group during follow-up (p < 0.001).Conclusion: In our study, the older age of onset in PD patients resulted in a higher incidence rate of dementia. In the young age of PD patients, the incidence rate of dementia was lower than the older PD patients, but the dementia risk was higher than controls of the same age. These findings possibly implied that there were different pathogenesis and pathologies causing dementia in younger and older PD patients.

Highlights

Parkinson’s disease (PD) manifests with dominant motor symptoms and a wide range of non-motor symptoms (NMS)
There were more patients with hypertension and diabetes mellitus (DM) in the PD group compared to the non-PD group
There were no significant differences in age, sex, hyperlipidemia, chronic kidney disease (CKD), and ischemic heart disease (IHD) between the PD and non-PD groups

Summary

Introduction

Parkinson’s disease (PD) manifests with dominant motor symptoms and a wide range of non-motor symptoms (NMS). In the CamPaIGN cohort in the UK, 57% of patients developed cognitive deficits within 3.5 years, and the estimated dementia incidence was about 38.7 per 1,000 person-years of observation [6]. In a prospective study in a Sydney cohort, 48% of PD patients developed dementia within 15 years after diagnosis, and the cumulative incidence was 83% at 20 years after the diagnosis [7, 8]. Cortical or limbic Lewy-related pathology (LP), coincidence Alzheimer-type pathology, and subcortical pathology are three types of pathology that might cause PD-D [9]. These pathologies may result in the impaired projection of dopamine, noradrenaline, serotonin, and acetylcholine neurons to the neocortex [10]. The widespread involvement of the brain and neocortical areas at Braak PD stages 5 and 6 seems to have the strongest pathological correlation with PD-D, and coexisting amyloid-β plaques and tau-containing neurofibrillary tangles may lead to a worse prognosis [11,12,13]

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