Mild traumatic brain injury is associated with reduced cortical thickness in those at risk for Alzheimer's disease
Hayes JP, Logue MW, Sadeh N, Spielberg JM, Verfaellie M, Hayes SM, Reagan A, Salat DH et al.. Brain : a journal of neurology, 2017-03-01
Topic: Amyloid, tau and blood-test diagnosis
Moderate-to-severe traumatic brain injury is one of the strongest environmental risk factors for the development of neurodegenerative diseases such as late-onset Alzheimer's disease, although it is unclear whether mild traumatic brain injury, or concussion, also confers risk. This study examined mild traumatic brain injury and genetic risk as predictors of reduced cortical thickness in brain regions previously associated with early Alzheimer's disease, and their relationship with episodic memory. Participants were 160 Iraq and Afghanistan War veterans between the ages of 19 and 58, many of whom carried mild traumatic brain injury and post-traumatic stress disorder diagnoses. Whole-genome polygenic risk scores for the development of Alzheimer's disease were calculated using summary statistics from the largest Alzheimer's disease genome-wide association study to date. Results showed that mild traumatic brain injury moderated the relationship between genetic risk for Alzheimer's disease and cortical thickness, such that individuals with mild traumatic brain injury and high genetic risk showed reduced cortical thickness in Alzheimer's disease-vulnerable regions. Among males with mild traumatic brain injury, high genetic risk for Alzheimer's disease was associated with cortical thinning as a function of time since injury. A moderated mediation analysis showed that mild traumatic brain injury and high genetic risk indirectly influenced episodic memory performance through cortical thickness, suggesting that cortical thinning in Alzheimer's disease-vulnerable brain regions is a mechanism for reduced memory performance. Finally, analyses that examined the apolipoprotein E4 allele, post-traumatic stress disorder, and genetic risk for schizophrenia and depression confirmed the specificity of the Alzheimer's disease polygenic risk finding. These results provide evidence that mild traumatic brain injury is associated with greater neurodegeneration and reduced memory performance in individuals at genetic risk for Alzheimer's disease, with the caveat that the order of causal effects cannot be inferred from cross-sectional studies. These results underscore the importance of documenting head injuries even within the mild range as they may interact with genetic risk to produce negative long-term health consequences such as neurodegenerative disease.
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APA 7th
Hayes, J. P., Logue, M. W., Sadeh, N., Spielberg, J. M., Verfaellie, M., Hayes, S. M., et al. (2017). Mild traumatic brain injury is associated with reduced cortical thickness in those at risk for Alzheimer's disease. Brain : a journal of neurology. https://doi.org/10.1093/brain/aww344
Vancouver
Hayes JP, Logue MW, Sadeh N, Spielberg JM, Verfaellie M, Hayes SM, et al. Mild traumatic brain injury is associated with reduced cortical thickness in those at risk for Alzheimer's disease. Brain : a journal of neurology. 2017. doi:10.1093/brain/aww344. PMID: 28077398.
BibTeX
@article{hayes2017-28077398,
author = {Hayes, J. P. and Logue, M. W. and Sadeh, N. and Spielberg, J. M. and Verfaellie, M. and Hayes, S. M. and Reagan, A. and Salat, D. H. and others},
title = {{Mild traumatic brain injury is associated with reduced cortical thickness in those at risk for Alzheimer's disease}},
journal = {Brain : a journal of neurology},
year = {2017},
doi = {10.1093/brain/aww344},
pmid = {28077398},
url = {https://doi.org/10.1093/brain/aww344}
}
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Key findings
- This study examined mild traumatic brain injury and genetic risk as predictors of reduced cortical thickness in brain regions previously associated with early Alzheimer's disease, and their relationship with episodic memory.
- Results showed that mild traumatic brain injury moderated the relationship between genetic risk for Alzheimer's disease and cortical thickness, such that individuals with mild traumatic brain injury and high genetic risk showed reduced cortical thickness in Alzheimer's disease-vulnerable regions.
- Among males with mild traumatic brain injury, high genetic risk for Alzheimer's disease was associated with cortical thinning as a function of time since injury.
- A moderated mediation analysis showed that mild traumatic brain injury and high genetic risk indirectly influenced episodic memory performance through cortical thickness, suggesting that cortical thinning in Alzheimer's disease-vulnerable brain regions is a mechanism for reduced memory performance.
- These results provide evidence that mild traumatic brain injury is associated with greater neurodegeneration and reduced memory performance in individuals at genetic risk for Alzheimer's disease, with the caveat that the order of causal effects cannot be inferred from cross-sectional studies.
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Study details
- Study designcross-sectional
- Evidence strengthLow
How this study scored 48/100
Published in a leading specialty journal, and it is a snapshot of people at one point in time. Scored zero for sample size, effect reported, studied in people and randomised / blinded because the record does not state it. We have no data on journal's citation record, times cited, citations per year, impact for its field and year, cited by studies here, still being cited, senior author's track record, institution's track record and multi-centre collaboration, so those were left out: it earned 28 of the 58 points we could judge it on, which is 48 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 9 / 10 | Tier 2 — leading specialty journal (Brain : a journal of neurology) |
| Journal's citation record | — / 4 | No journal record from OpenAlex — left out of this score |
| Study design | 4 / 12 | A snapshot of people at one point in time |
| 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 | 2 / 5 | 2017 — within 10 year(s) of the newest study here |
| Sample size | 0 / 4 | Participant count not stated — scores zero (not stated in the record — scored 0) |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 0 / 3 | Not stated whether this was studied in people — scores zero (not stated in the record — scored 0) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | — / 7 | No citation count (not found in OpenAlex) — left out of this score |
| Citations per year | — / 5 | No citation count or no year — left out of this score |
| Impact for its field and year | — / 6 | No field-weighted citation impact (OpenAlex has none yet) — left out of this score |
| Cited by studies here | — / 6 | Not yet checked against this library's citation graph — left out of this score |
| Still being cited | — / 4 | No yearly citation counts — left out of this score |
| Senior author's track record | — / 4 | Senior author's record not available — left out of this score |
| Institution's track record | — / 3 | No institution listed in OpenAlex — left out of this score |
| Multi-centre collaboration | — / 3 | Institutions not listed — left out of this score |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 28077398) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Points | 28 / 58 | Scored on 11 of 20 parts. We have no data for the rest, so they are left out: 28 of the 58 points we could judge it on is 48 out of 100. |
| Total | 48 / 100 | — |
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