Early-Life Factors and Risk of Parkinson's Disease: A Register-Based Cohort Study

Long-term Risk of Parkinson Disease Following Influenza and Other Infections

Importance

Influenza has been associated with the risk of developing Parkinson disease, but the association is controversial.

Objective

To examine whether prior influenza and other infections are associated with Parkinson disease more than 10 years after infection.

Design, Setting, and Participants

This case-control study used data from 1977 to 2016 from the Danish National Patient Registry. All individuals with Parkinson disease, excluding those with drug-induced parkinsonism, were included and matched to 5 population controls on sex, age, and date of Parkinson diagnosis. Data were analyzed from December 2019 to September 2021.

Exposures

Infections were ascertained between 1977 and 2016 and categorized by time from infection to Parkinson disease diagnosis. To increase specificity of influenza diagnoses, influenza exposure was restricted to months of peak influenza activity.

Main Outcomes and Measures

Parkinson disease diagnoses were identified between January 1, 2000, and December 31, 2016. Crude and adjusted odds ratios (ORs) and 95% CIs were calculated by conditional logistic regression overall and stratified by time between infection and Parkinson disease (5 years or less, more than 5 to 10 years, more than 10 years).

Results

Of 61 626 included individuals, 23 826 (38.7%) were female, and 53 202 (86.3%) were older than 60 years. A total of 10 271 individuals with Parkinson disease and 51 355 controls were identified. Influenza diagnosed at any time during a calendar year was associated with Parkinson disease more than 10 years later (OR, 1.73; 95% CI, 1.11-2.71). When influenza exposure was restricted to months of highest influenza activity, an elevated OR with a wider confidence interval was found (OR, 1.52; 95% CI, 0.80-2.89). There was no evidence of an association with any type of infection more than 10 years prior to Parkinson disease (OR, 1.04; 95% CI, 0.98-1.10). Several specific infections yielded increased odds of Parkinson disease within 5 years of infection, but results were null when exposure occurred more than 10 years prior.

Conclusions and Relevance

In this case-control study, influenza was associated with diagnoses of Parkinson disease more than 10 years after infection. These observational data suggest a link between influenza and Parkinson disease but do not demonstrate causality. While other infections were associated with Parkinson disease diagnoses soon after infection, null associations after more than 10 years suggest these shorter-term associations are not causal.

Heterogeneity of prodromal Parkinson symptoms in siblings of Parkinson disease patients

A prodromal phase of Parkinson's disease (PD) may precede motor manifestations by decades. PD patients' siblings are at higher risk for PD, but the prevalence and distribution of prodromal symptoms are unknown. The study objectives were (1) to assess motor and non-motor features estimating prodromal PD probability in PD siblings recruited within the European PROPAG-AGEING project; (2) to compare motor and non-motor symptoms to the well-established DeNoPa cohort. 340 PD siblings from three sites (Bologna, Seville, Kassel/Goettingen) underwent clinical and neurological evaluations of PD markers. The German part of the cohort was compared with German de novo PD patients (dnPDs) and healthy controls (CTRs) from DeNoPa. Fifteen (4.4%) siblings presented with subtle signs of motor impairment, with MDS-UPDRS-III scores not clinically different from CTRs. Symptoms of orthostatic hypotension were present in 47 siblings (13.8%), no different to CTRs (p = 0.072). No differences were found for olfaction and overall cognition; German-siblings performed worse than CTRs in visuospatial-executive and language tasks. 3/147 siblings had video-polysomnography-confirmed REM sleep behavior disorder (RBD), none was positive on the RBD Screening Questionnaire. 173/300 siblings had <1% probability of having prodromal PD; 100 between 1 and 10%, 26 siblings between 10 and 80%, one fulfilled the criteria for prodromal PD. According to the current analysis, we cannot confirm the increased risk of PD siblings for prodromal PD. Siblings showed a heterogeneous distribution of prodromal PD markers and probability. Additional parameters, including strong disease markers, should be investigated to verify if these results depend on validity and sensitivity of prodromal PD criteria, or if siblings' risk is not elevated.

Farming, well water consumption, rural living, and pesticide exposure in early life as the risk factors for Parkinson disease in Igdir province

OBJECTIVE

To investigate potential risk factors for Parkinson`s disease (PD) in elderly individuals rural living in Turkey.

METHODS

In total, 72 consecutive elderly Parkinson disease patients referred to the Neurology Clinic, Igdir State Hospital, Igdir, Turkey were included in the study. A structured questionnaire comprising questions on history of pastoral living, pit water consumption, and exposure to ionizing radiation and pesticides was administered to the patients. The patients were divided into 2 groups on the basis of water consumption: well water consumption group and city network consumption group.

RESULTS

Of 72 patients with PD, 49 (68.1%) exposed to well water while 23 (31.9%) did not exposed to well water. The average duration of well water consumption was 20 (standard deviation 6) years (p less than 0.01) in group 1. Nitrate, sulfate and heavy metal levels were significantly higher in well water than in city network water (p less than 0.05).

CONCLUSION

Consumption of well water containing heavy metals and nitrates in early life may contribute to the etiology of Parkinson disease in elderly individuals in Igdir province of Turkey.

Infections or Sepsis Preceding Clinically Diagnosed α-Synucleinopathies: A Case-Control Study

BACKGROUND

Several studies have proposed a role for infections to induce an inflammatory response triggering Parkinson's disease. This remains controversial and the influence of severe infections on other α-synucleinopathies (Dementia with Lewy Bodies, Parkinson's disease dementia, and Multiple System Atrophy) has not been adequately investigated.

OBJECTIVES

To assess the association between hospitalization-required infections or sepsis and risk of clinically diagnosed α-synucleinopathies.

METHODS

Using the medical records-linkage system (Rochester Epidemiology Project), we identified all α-synucleinopathy cases of in Olmsted County (1991-2010). Cases were matched by symptom-onset age and sex to controls. We reviewed complete medical records to detect hospital-required infections or sepsis preceding clinical-motor onset of α-synucleinopathies. We used conditional logistic regression to calculate the odds ratio of all α-synucleinopathies, adjusting for medications, coffee, and smoking.

RESULTS

There was no association between infection-related hospitalization (odds ratio: 1.05; 95% confidence interval: 0.78-1.40; P = 0.76) or sepsis (odds ratio: 0.86; 95% confidence interval: 0.40-1.85; P = 0.70) and all α-synucleinopathies in multivariable analyses. We did not identify any associations after stratifying for type of α-synucleinopathy, sex, and age at clinical-motor onset. We analyzed sepsis separately with similar results.

CONCLUSION

We did not observe any associations between infections leading to hospitalization or sepsis and development of any α-synucleinopathies. © 2020 International Parkinson and Movement Disorder Society.

Dysphagia in Parkinson's Disease Improves with Vocal Augmentation

While voice-related disorders in Parkinson's disease (PD) are commonly discussed in the literature, dysphagia in PD is less widely published. Vocal fold augmentation, including injection laryngoplasty (IL), is a well-established treatment for glottal insufficiency (Cates et al. in Otolaryngol Head Neck Surg 155(3):454-457, 2016). This study aimed to observe the effects of IL in PD patients with vocal bowing, with or without therapy, on glottic closure and patient-reported dysphagia outcomes. The study design was based on retrospectively collected database and cohort-case series. PD patients selected for retrospective review over a 2-year period were referred and evaluated in the Voice, Swallowing, and Airway multidisciplinary clinic by speech language pathologist and laryngologist, and were undergoing IL. Charts were reviewed for age, gender, Body Mass Index (BMI), onset of PD, and Movement Disorders Society-Unified Parkinson's Disease Rating Scale Part 3 (MDS-UPDRS) scoring. We compared pre/postoperatively (> 1 < 3 months) using validated patient-reported outcome tools: Reflux Symptom Index (RSI), Glottal Function Index (GFI), Eating Assessment Tool-10 (EAT), and stroboscopic examinations. The study included 14 patients undergoing 22 IL or 1.6 IL/patient: mean age 70 years (63-80), 100% male, and BMI 25.9 ± 4.3 (mean ± SD). MDS-UPDRS scoring 33 ± 20 (moderate severity), with time between PD diagnosis and IL 8 ± 10 years. All patients had pre- and post-stroboscopic examinations; however, only 4:14 underwent formal swallowing evaluation. Overall, 14 IL patients improved on patient-reported measures (ΔRSI = 4; ΔGFI = 3; ΔEAT = 4). Based on the findings of the study, we conclude that PD is a progressive neurodegenerative condition with dysphagia. The presented pilot data suggest that IL may be considered as a beneficial adjunct for PD patients with glottal insufficiency. LEVEL OF EVIDENCE: 4.

New transgenic models of Parkinson's disease using genome editing technology

INTRODUCTION

Parkinson's disease (PD) is the second most common neurodegenerative disorder. It is characterised by selective loss of dopaminergic neurons in the substantia nigra pars compacta, which results in dopamine depletion, leading to a number of motor and non-motor symptoms.

DEVELOPMENT

In recent years, the development of new animal models using nuclease-based genome-editing technology (ZFN, TALEN, and CRISPR/Cas9 nucleases) has enabled the introduction of custom-made modifications into the genome to replicate key features of PD, leading to significant advances in our understanding of the pathophysiology of the disease.

CONCLUSIONS

We review the most recent studies on this new generation of in vitro and in vivo PD models, which replicate the most relevant symptoms of the disease and enable better understanding of the aetiology and mechanisms of PD. This may be helpful in the future development of effective treatments to halt or slow disease progression.