Molecular Biomarkers Associated with Traumatic Brain Injury Outcome in Individuals of Black Racial Identity or African Ancestry: A Narrative Review.

Traumatic brain injury (TBI) is a leading cause of death and disability worldwide and a major global health concern. In the United States, individuals of Black or African American racial identity experience disproportionately higher rates of TBI and suffer from worse postinjury outcomes. Contemporary research agendas have largely overlooked or excluded Black populations, resulting in the continued marginalization of Black patient populations in TBI studies, thereby limiting the generalizability of ongoing research to patients in the United States and around the world. This review aims to highlight what is currently known, and identify knowledge gaps, in research on molecular biomarkers associated with TBI in Black populations. A PubMed literature search was conducted to identify studies that investigate molecular biomarkers associated with TBI outcomes that include participants of Black racial identity and those of African ancestry. Studies identified for this review investigate biomarkers associated with TBI outcomes through a lens that specifically examines race, ethnicity, or ancestry. Most studies focused on blood- or cerebrospinal fluid-derived protein biomarkers. Studies identified statistical variation in S100ß, ubiquitin C-terminal hydrolase-L1, amyloid-ß, and tau across participant race, either at baseline or following TBI. Additionally, several studies identified genetic polymorphisms associated with TBI outcomes related to apolipoprotein E, ANKK1, and COMT polymorphism and TBI outcome and identified allele frequency variation across population ancestry. The role of race and ancestry on biomarkers associated with TBI outcome remains indeterminate and subsequent work is still required to understand the implications for patients with TBI.