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Traumatic brain injury in later life increases risk for Parkinson disease
Gardner RC, Burke JF, Nettiksimmons J, Goldman S, Tanner CM, Yaffe K.. Annals of neurology, 2015-03-28
Topic: Brain proteins, microglia and lab models
Plain-language summary
Objective Traumatic brain injury (TBI) is thought to be a risk factor for Parkinson disease (PD), but results are conflicting. Many studies do not account for confounding or reverse causation. We sought to address these concerns by quantifying risk of PD after TBI compared to non-TBI trauma (NTT; defined as fractures). Methods Using inpatient/emergency department (ED) International Classification of Disease, Ninth Revision code data for California hospitals from 2005-2006, we identified patients aged ≥55 years with TBI (n = 52,393) or NTT (n = 113,406) and without baseline PD or dementia who survived hospitalization. Using Kaplan-Meier estimates and Cox proportional hazards models (adjusted for age, sex, race/ethnicity, income, comorbidities, health care use, and trauma severity), we estimated risk of PD after TBI during follow-up ending in 2011. We also assessed interaction with mechanism of injury (fall vs nonfall) and effect of TBI severity (mild vs moderate/severe) and TBI frequency (1 TBI vs >1 TBI). Results TBI patients were significantly more likely to be diagnosed with PD compared to NTT patients (1.7% vs 1.1%, p 1 TBI: HR = 1.87, 95% CI = 1.58-2.21) revealed a dose response. Interpretation Among patients aged ≥55 years presenting to inpatient/ED settings with trauma, TBI is associated with a 44% increased risk of developing PD over 5 to 7 years that is unlikely to be due to confounding or reverse causation.
What this study adds
Evidence grade: Low
The record lists 52,393 participants. Among patients aged 55 and older with trauma, traumatic brain injury was linked to a 44% higher risk of developing Parkinson's disease over 5 to 7 years, with a dose response for repeated injuries. Reported effect size: 1.7%; 1.1%; HR = 1.87.
Taken from this record’s own fields, not from reading the paper. The grade is assigned from the abstract’s wording; what that means.
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
APA 7th
Gardner, R. C., Burke, J. F., Nettiksimmons, J., Goldman, S., Tanner, C. M., & Yaffe, K. (2015). Traumatic brain injury in later life increases risk for Parkinson disease. Annals of neurology. https://doi.org/10.1002/ana.24396
Vancouver
Gardner RC, Burke JF, Nettiksimmons J, Goldman S, Tanner CM, Yaffe K. Traumatic brain injury in later life increases risk for Parkinson disease. Annals of neurology. 2015. doi:10.1002/ana.24396. PMID: 25726936.
BibTeX
@article{gardner2015-25726936,
author = {Gardner, R. C. and Burke, J. F. and Nettiksimmons, J. and Goldman, S. and Tanner, C. M. and Yaffe, K.},
title = {{Traumatic brain injury in later life increases risk for Parkinson disease}},
journal = {Annals of neurology},
year = {2015},
doi = {10.1002/ana.24396},
pmid = {25726936},
url = {https://doi.org/10.1002/ana.24396}
}
Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. Check the citation against the original before you use it.
Key findings
- Objective Traumatic brain injury (TBI) is thought to be a risk factor for Parkinson disease (PD), but results are conflicting.
- We sought to address these concerns by quantifying risk of PD after TBI compared to non-TBI trauma (NTT; defined as fractures).
- Results TBI patients were significantly more likely to be diagnosed with PD compared to NTT patients (1.7% vs 1.1%, p 1 TBI: HR = 1.87, 95% CI = 1.58-2.21) revealed a dose response.
- Interpretation Among patients aged ≥55 years presenting to inpatient/ED settings with trauma, TBI is associated with a 44% increased risk of developing PD over 5 to 7 years that is unlikely to be due to confounding or reverse causation.
Why it matters
Among patients aged 55 and older with trauma, traumatic brain injury was linked to a 44% higher risk of developing Parkinson's disease over 5 to 7 years, with a dose response for repeated injuries. This is about Parkinson's disease risk and does not address treating, curing or preventing Alzheimer's disease.
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Study details
- Participants52,393
- Effect size1.7%; 1.1%; HR = 1.87
- Evidence strengthLow
How this study scored 63/100
Published in a leading specialty journal. Scored zero for study design and randomized / blinded because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 9 / 10 | Tier 2 — leading specialty journal (Annals of neurology) |
| Journal's citation record | 3 / 4 | Annals of Neurology: journal h-index 437 (OpenAlex, 2026-10-29) |
| Study design | 0 / 12 | No study design recorded — scores zero, not guessed (not stated in the record — scored 0) |
| Strength of evidence | 1 / 5 | Rated “low” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 1 / 5 | 2015 — within 20 year(s) of the newest study here |
| Sample size | 4 / 4 | 52,393 participants |
| Effect reported | 3 / 3 | Effect reported with a statistic (interval, p-value, ratio or similar) |
| Studied in people | 3 / 3 | Studied in people (participant count stated) |
| Randomized / blinded | 0 / 2 | No randomization or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | 5 / 7 | Cited 288 times (OpenAlex, 2026-10-10) |
| Citations per year | 4 / 5 | 22.2 citations a year over 13 year(s) since 2015 |
| Impact for its field and year | 5 / 6 | Cited 20.9× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 2 / 6 | Cited by 7 other studies in this library |
| Still being cited | 3 / 4 | Cited 55 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 4 / 4 | Last-listed author Kristine S. Yaffe: h-index 155 (OpenAlex, whole career) |
| Institution's track record | 2 / 3 | University of Michigan: institution h-index 2,240 (OpenAlex) |
| Multicenter collaboration | 2 / 3 | OpenAlex lists 6 institution(s) in 1 country |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 25726936) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Total | 63 / 100 | — |
What each of these 20 components measures, and what this score is not →
Read the original
- DOI: 10.1002/ana.24396
- PubMed: 25726936
- Original source →
- Free full text: eScholarship (California Digital Library) →
Full text: free to read — OpenAlex lists this copy as free to read: the link above (checked 6 Feb 1020).
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