Dementia Outcomes among Individuals with a History of Traumatic Brain Injury: Differences by Race and Sex



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Traumatic brain injury (TBI) is an important public health concern with 20-50% of US adults having sustained a TBI during their lifetime. There is growing evidence to postulate that individuals with a history of TBI may be at greater risk of cognitive decline and dementia in later life, but additional research is needed to better understand this relationship. Research suggests both dementia and TBI outcomes may differ by race/ethnicity and sex/gender suggesting dementia outcomes following TBI may also be impacted by these demographic factors. The purpose of this study was to build upon past literature examining the relationship between TBI history and diagnosis and severity of dementia in later life by focusing on the influence of race/ethnicity and sex in a large, ethnically diverse, civilian sample of older adults with a TBI history while also considering potential contributions from social determinants of health (i.e., income, health insurance, education, etc.). The final sample consisted of 1242 older adults, 261 of whom reported a history of TBI based on the Ohio State University TBI Identification interview, from the Health and Aging Brain Study: Health Disparities (HABS-HD) study database. Outcome variables were dementia diagnosis (Y/N) determined by Clinical Dementia Rating Scale (CDR) sum of boxes score of 2.5 or greater and dementia severity (total sum of boxes). In the full sample, 69 (5.6%) individuals met criteria for dementia diagnosis and among the sub-sample with TBI history, 11 (4.2%) had a dementia diagnosis. Analyses included correlations, chi-squares, t-tests, and regressions to address study aims. The results revealed no significant relationship between TBI history and dementia outcomes. Neither race/ethnicity nor sex significantly predicted dementia outcome. The interaction between race/ethnicity and sex also did not significantly predict either outcome. However, health and sociodemographic factors that significantly contributed to predicting dementia outcomes included income and age with the full sample and history of high blood pressure among individuals with the TBI sample. The low frequency of TBI history and low percentage of people with dementia diagnosis may have impacted these findings. Further study of the relationship between TBI and dementia in later life is required. Future directions and potential mechanisms for the link between TBI and dementia are discussed.



Traumatic brain injury, Dementia