Traumatic brain injury preceding clinically diagnosed α-synucleinopathies: A case-control study

Area of Science:

• Neurology
• Neuroscience
• Epidemiology

Background:

• Traumatic brain injury (TBI) is a potential risk factor for neurodegenerative diseases.
• α-synucleinopathies, including Parkinson disease (PD), dementia with Lewy bodies (DLB), PD dementia (PDD), and multiple system atrophy (MSA), are characterized by the accumulation of α-synuclein protein.
• The relationship between TBI and α-synucleinopathies requires further investigation.

Purpose of the Study:

• To investigate the association between traumatic brain injury (TBI) and the risk of developing clinically diagnosed α-synucleinopathies.
• To examine specific associations between TBI and individual α-synucleinopathies: PD, DLB, PDD, and MSA.

Main Methods:

• A nested case-control study was conducted using the Rochester Epidemiology Project medical records.
• Incident cases of α-synucleinopathies (1991-2010) were identified and matched to controls by age and sex.
• TBI history, severity, and timing were assessed, and conditional-logistic regression was used to calculate odds ratios, adjusting for coffee intake and smoking.

Main Results:

• TBI occurred less frequently in cases (7.0%) than controls (8.2%).
• No significant association was found between TBI and all α-synucleinopathies combined (OR 0.90, 95% CI 0.54-1.52) in multivariable analyses.
• No associations were identified for TBI with PD, DLB, or PDD. A single case of TBI was noted in the MSA group, precluding robust analysis.

Conclusions:

• This population-based study found no evidence of an association between TBI and the subsequent development of α-synucleinopathies.
• The lack of association persisted regardless of TBI temporality or severity.
• Study findings may be limited by statistical power.