Posttraumatic Epilepsy and Dementia Risk.

Importance: Although both head injury and epilepsy are associated with long-term dementia risk, posttraumatic epilepsy (PTE) has only been evaluated in association with short-term cognitive outcomes. Objective: To investigate associations of PTE with dementia risk. Design, Setting, and Participants: The Atherosclerosis Risk in Communities (ARIC) study initially enrolled participants from 1987 to 1989 and this prospective cohort study uses data through December 31, 2019, with a median follow-up of 25 years. Data were analyzed between March 14, 2023, and January 2, 2024. The study took place in 4 US communities in Minnesota, Maryland, North Carolina, and Mississippi. Of 15 792 ARIC study participants initially enrolled, 2061 were ineligible and 1173 were excluded for missing data, resulting in 12 558 included participants. Exposures: Head injury was defined by self-report and International Classification of Diseases (ICD) diagnostic codes. Seizure/epilepsy was defined using ICD codes. PTE was defined as a diagnosis of seizure/epilepsy occurring more than 7 days after head injury. Head injury, seizure/epilepsy, and PTE were analyzed as time-varying exposures. Main Outcomes and Measures: Dementia was defined using cognitive assessments, informant interviews, and ICD and death certificate codes. Adjusted Cox and Fine and Gray proportional hazards models were used to estimate dementia risk. Results: Participants had a mean (SD) age of 54.3 (5.8) years at baseline, 57.7% were female, 28.2% were of self-reported Black race, 14.4% were ultimately categorized as having head injury, 5.1% as having seizure/epilepsy, and 1.2% as having PTE. Over a median follow-up of 25 (25th to 75th percentile, 17-30) years, 19.9% developed dementia. In fully adjusted models, compared with no head injury and no seizure/epilepsy, PTE was associated with 4.56 (95% CI, 4.49-5.95) times the risk of dementia, while seizure/epilepsy was associated with 2.61 (95% CI, 2.21-3.07) times the risk and head injury with 1.63 (95% CI, 1.47-1.80) times the risk. The risk of dementia associated with PTE was significantly higher than the risk associated with head injury alone and with nontraumatic seizure/epilepsy alone. Results were slightly attenuated in models accounting for the competing risks of mortality and stroke, but patterns of association remained similar. In secondary analyses, the increased dementia risk associated with PTE occurring after first vs second head injury and after mild vs moderate/severe injury was similar. Conclusions and Relevance: In this community-based cohort, there was an increased risk of dementia associated with PTE that was significantly higher than the risk associated with head injury or seizure/epilepsy alone. These findings provide evidence that PTE is associated with long-term outcomes and supports both the prevention of head injuries via public health measures and further research into the underlying mechanisms and the risk factors for the development of PTE, so that efforts can also be focused on the prevention of PTE after a head injury.

Trends in Traumatic Brain Injury Mortality in the US.

This cohort study characterizes US trends in traumatic brain injury­related mortality by age, sex, and race and ethnicity.

Associations Between Head Injury and Subsequent Risk of Falls: Results From the Atherosclerosis Risk in Communities (ARIC) Study.

BACKGROUND AND OBJECTIVES: Falls are a leading cause of head injury among older adults, but the risk of fall occurring after a head injury is less well-characterized. We sought to examine the association between head injury and subsequent risk of falls requiring hospital care among community-dwelling older adults. METHODS: This analysis included 13,081 participants in the Atherosclerosis Risk in Communities Study enrolled in 1987-1989 and followed through 2019. The association of head injury (time-varying exposure, self-reported and/or ICD-9/10 code identified) with the risk of subsequent (occurring >1-month after head injury) falls requiring hospital care (ICD-9/10 code defined) was modeled using Cox proportional hazards regression. Secondary analyses included Fine and Gray proportional hazards regression to account for the competing risk of death, analysis of head injury frequency and severity, and formal testing for interaction by age, sex, and race. Models were adjusted for age, sex, race/center, education, military service, alcohol consumption, smoking, diabetes, hypertension, and psychotropic medication use. RESULTS: The mean age of participants at baseline was 54 years, 58% were female, 28% were Black, and 14% had at least one head injury occurring over the study period. Over a median 23 years of follow-up, 29% of participants had a fall requiring medical care. In adjusted Cox proportional hazards models, individuals with head injury had 2.01 (95% CI 1.85-2.18) times the risk of falls compared with individuals without head injury. Accounting for the competing risk of mortality, individuals with head injury had 1.69 (95% CI 1.57-1.82) times the risk of falls compared with individuals without head injury. We observed stronger associations among men compared with women (men: hazard ratio [HR] = 2.60, 95% CI 2.25-3.00; women: HR = 1.80, 95% CI 1.63-1.99, p-interaction <0.001). We observed evidence of a dose-response association for head injury number and severity with fall risk (1 injury: HR = 1.68, 95% CI 1.53-1.84; 2+ injuries: HR = 2.37, 95% CI 1.92-2.94 and mild: HR = 1.97, 95% CI 1.78-2.18; moderate/severe/penetrating: HR = 2.50, 95% CI 2.06-3.02). DISCUSSION: Among community-dwelling older adults followed over 30 years, head injury was associated with subsequent falls requiring medical care. We observed stronger associations among men and with increasing number and severity of head injuries. Whether older individuals with head injury might benefit from fall prevention measures should be a focus of future research.