Traumatic brain injury (TBI), very common in the United States (US) and occurring at highest rates in older adulthood, is a documented risk factor for cognitive impairment and dementia. However, the full scope of the problem is unknown, as comparative incidence of TBI among older adults is poorly characterized. Moreover, the effect of demographics (race/ethnicity, sex) and cognitive and medical status, as well as education, socioeconomic status, and other social determinants of health (SDOH) on TBI risk is not well understood. We aimed to explore the impact of demographics, cognitive and medical status, and SDOH on vulnerability to new TBIs among older adults.

Enrollees 65 and older in the nationally representative Health and Retirement Study (HRS) who consented to have their survey data linked to Medicare claims and had not experienced a head injury prior to HRS enrollment were studied. We used claims data 2000-2018 to obtain incident TBI diagnoses and harnessed the detailed demographic, cognitive, medical, and SDOH information available in the HRS. Incident TBI was defined using inpatient and outpatient International Classification of Disease (ICD 9 and 10) codes received the same day as an emergency room (ER) visit code and a computed tomography (CT) scan code, occurring after the enrollee’s baseline HRS interview. We calculated descriptive statistics and bivariate associations for TBI status with demographic and SDOH characteristics measured at baseline using sample weights to account for the complex survey design.

Of respondents meeting inclusion criteria (n=9273) during the study follow-up period of 18 years, 8.9% received emergency room treatment for a TBI. Older adults who experienced TBI during the study period were more likely to be female (p=0.0006), and white (p=0.0001), to have normal cognition (vs. cognitive impairment or dementia, p=0.0011), higher education (p<0.0001), and higher income (p=0.01). Having lung disease (p=0.0003) or functional impairment (p=0.03) at baseline were protective against experiencing a TBI.

Our results suggest that almost 9% of US older adults received ER treatment for a new TBI during the 18-year study period, and that race, sex, and SDOH factors may increase risk for, or be protective against, TBI. This novel investigation into the impact of demographics and SDOH on incident TBI suggests access to care may impact who gets treatment for TBI. Further study is indicated and may lead to opportunities for both targeted intervention (e.g., primary TBI prevention) to groups most at risk as well as identification and mollification of the most relevant structural and contextual factors (e.g., access to care) to reduce risk of TBI among older adults.