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

Research Objectives: To examine the relationship between TBI history and dementia outcomes in later life. Uniquely, this study focused on the influence of race/ethnicity, sex, and social determinants of health (i.e., income, health insurance, years of education) using a large community-based sample of Mexican Americans and non-Hispanic White Americans ages 50 years and older.

Design: Cohort Study

Setting: Data from the Health and Aging Brain Study: Health Disparities (HABS-HD) project were used for these secondary analyses.

Participants: The initial sample consisted of 1705 participants. Participants were excluded if they did not have valid data on TBI history (n=337), reported ethnoracial background outside of Hispanic or non-Hispanic white (n=6), had a history of stroke (n=56) or seizure (n=27), or did not have valid data on income (n=31) or insurance status (n=6). The final sample included 1242 participants.

Interventions: Not applicable.

Main Outcome Measures: Dementia diagnosis (Sum of Boxes score of ≥ 2.5) and dementia severity (total Sum of Boxes score) per Clinical Dementia Rating scale.

Results: While the results revealed no significant relationship between TBI history and dementia outcomes, there were meaningful contributions from income and age in the full sample. When examining dementia outcomes within the TBI sample, neither ethnicity nor sex significantly predicted dementia outcomes. However, high blood pressure contributed to predicting dementia outcomes within the TBI sample (ps <.05) with 90.9% of individuals in the positive dementia group reporting hypertension compared to 46.4% of individuals in the non-dementia group (ꭓ2=8.36, p=.004; OR=11.55 [1.46–91.60]).

Conclusions: Although the current study did not find TBI history, ethnicity, or sex to be meaningfully linked with dementia outcomes, it was revealed that hypertension among people with TBI history was meaningfully linked to dementia outcomes. Research indicates a relationship between hypertension and inflammation, which may be a pathway connecting TBI exposure to later dementia diagnosis and severity. Further exploration of hypertension as an indicator of chronic inflammation among people with TBI is warranted.

Author(s) Disclosures: Drs. Sander and Williams disclose grant funding from the National Institute on Disability, Independent Living, and Rehabilitation Research.