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Impact of aging on the immune response to traumatic brain injury (AIm:TBI) study protocol
  1. Hilaire J Thompson1,2,
  2. Frederick Rivara2,3,
  3. Kyra J Becker4,5,
  4. Ronald Maier2,6,
  5. Nancy Temkin5,7
  1. 1 Biobehavioral Nursing and Health Informatics, University of Washington, Seattle, Washington, USA
  2. 2 Harborview Injury Prevention and Research Center, University of Washington, Seattle, Washington, USA
  3. 3 Department of Pediatrics, University of Washington, Seattle, Washington, USA
  4. 4 Department of Neurology, University of Washington, Seattle, Washington, USA
  5. 5 Department of Neurological Surgery, University of Washington, Seattle, Washington, USA
  6. 6 Department of Surgery, University of Washington, Seattle, Washington, USA
  7. 7 Department of Biostatistics, School of Public Health, University of Washington, Seattle, Washington, USA
  1. Correspondence to Dr Hilaire J Thompson, Biobehavioral Nursing and Health Informatics, University of Washington, Seattle, WA 98195, USA; hilairet{at}


Background Traumatic brain injury (TBI) in older adults leads to considerable morbidity and mortality. Outcomes among older adults with TBI are disparately worse than in younger adults. Differences in immunological response to injury may account for at least some of this disparity. Understanding how ageing differentially affects the immune response to TBI and how older age and these immunological changes affect the natural history of recovery following TBI are the goals of this study.

Design/methods A prospective multiple cohort design is being used to assess the effects of ageing and TBI on immune makers and to test predictors of impairment and disability in older adults following mild TBI. Older adults (>55 years) with mild TBI are enrolled with three comparison groups: younger adults (21–54 years) with mild TBI, non-injured older adults (>55 years) and non-injured young adults (21–54 years). For the primary analysis, we will assess the association between immune markers and Glasgow Outcome Scale-Extended at 6 months, using logistic regression. Predictors of interest will be inflammatory biomarkers. Multivariate linear regression will be used to evaluate associations between biomarkers and other outcomes (symptoms, function and quality of life) at 3 and 6 months. Exploratory analyses will investigate the utility of biomarkers to predict outcome using receiver-operating characteristic curves.

Discussion A better understanding of the recovery trajectory and biological rationale for disparate outcomes following TBI in older adults could allow for development of specific interventions aimed at reducing or eliminating symptoms. Such interventions could reduce impairment and healthcare costs.

  • brain injury
  • older adult
  • cohort study
  • disability
  • biomarkers
  • immune function

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  • Contributors HJT was responsible for the initial conception and drafting of the work. All listed authors made substantive contributions to the study design and revision of the work. All authors approved the final version.

  • Funding This work was supported by the National Institute of Neurological Disorders and Stroke of the National Institutes of Health under award number R01NS077913.

  • Disclaimer The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval University of Washington Institutional Review Board.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement There are no data in this work.