Prevalence of Lifetime History of Traumatic Brain Injury among Older Male Veterans Compared with Civilians: A Nationally Representative Study

Psychiatric Disorders Are Common Among Older US Veterans Prior to Traumatic Brain Injury

OBJECTIVE

To estimate the impact of traumatic brain injury (TBI) on prevalence of posttraumatic stress disorder (PTSD), depression, and alcohol and substance use disorders.

SETTING

A random sample of Veteran's Health Administration data.

PARTICIPANTS

A total of 14 116 veterans aged ≥55 with incident late-life TBI between October 1, 1999, and September 31, 2021, were matched 1:3 on age and TBI date to 42 678 veterans without TBI.

DESIGN

Retrospective cohort study.

MAIN MEASURES

PTSD, depression, and alcohol and substance use disorders were identified using diagnostic codes. Participants were censored after the first diagnosis during the year before and the year after the TBI or matched date. Prevalence rates of PTSD, depression, alcohol, and substance use disorders were compared before and after incident TBI or matched date using Poisson regression.

RESULTS

Pre-TBI prevalence rates of disorders were higher among those with TBI relative to those without TBI. Pre-TBI PTSD prevalence rates (per 1000 person-years) were 126.3 (95% CI, 120.2-132.4) compared to 21.5 (95% CI, 20.1-22.9) in the non-TBI cohort. In adjusted models, TBI was not associated with an increase in the prevalence of any of the studied disorders.

CONCLUSIONS

Prevalence rates of depression, PTSD, and alcohol and substance use disorders were 5 to 10 times higher among older veterans before incident TBI. We did not observe an increase in the prevalence of these disorders after incident TBI. Older veterans with these disorders may be at increased risk for TBI.

Incidence of Traumatic Brain Injury in a Longitudinal Cohort of Older Adults

Importance

Traumatic brain injury (TBI) occurs at the highest rate in older adulthood and increases risk for cognitive impairment and dementia.

Objectives

To update existing TBI surveillance data to capture nonhospital settings and to explore how social determinants of health (SDOH) are associated with TBI incidence among older adults.

Design, Setting, and Participants

This nationally representative longitudinal cohort study assessed participants for 18 years, from August 2000 through December 2018, using data from the Health and Retirement Study (HRS) and linked Medicare claims dates. Analyses were completed August 9 through December 12, 2022. Participants were 65 years of age or older in the HRS with survey data linked to Medicare without a TBI prior to HRS enrollment. They were community dwelling at enrollment but were retained in HRS if they were later institutionalized.

Exposures

Baseline demographic, cognitive, medical, and SDOH information from HRS.

Main Outcomes and Measures

Incident TBI was defined using inpatient and outpatient International Classification of Diseases, Ninth or Tenth Revision, diagnosis codes received the same day or within 1 day as the emergency department (ED) visit code and the computed tomography (CT) or magnetic resonance imaging (MRI) code, after baseline HRS interview. A cohort with TBI codes but no ED visit or CT or MRI scan was derived to capture diagnoses in nonhospital settings. Descriptive statistics and bivariate associations of TBI with demographic and SDOH characteristics used sample weights. Fine-Gray regression models estimated associations between covariates and TBI, with death as a competing risk. Imputation considering outcome and complex survey design was performed by race and ethnicity, sex, education level, and Area Deprivation Index percentiles 1, 50, and 100. Other exposure variables were fixed at their weighted means.

Results

Among 9239 eligible respondents, 5258 (57.7%) were female and 1210 (9.1%) were Black, 574 (4.7%) were Hispanic, and 7297 (84.4%) were White. Mean (SD) baseline age was 75.2 (8.0) years. During follow-up (18 years), 797 (8.9%) of respondents received an incident TBI diagnosis with an ED visit and a CT code within 1 day, 964 (10.2%) received an incident TBI diagnosis and an ED code, and 1148 (12.9%) received a TBI code with or without an ED visit and CT scan code. Compared with respondents without incident TBI, respondents with TBI were more likely to be female (absolute difference, 7.0 [95% CI, 3.3-10.8]; P < .001) and White (absolute difference, 5.1 [95% CI, 2.8-7.4]; P < .001), have normal cognition (vs cognitive impairment or dementia; absolute difference, 6.1 [95% CI, 2.8-9.3]; P = .001), higher education (absolute difference, 3.8 [95% CI, 0.9-6.7]; P < .001), and wealth (absolute difference, 6.5 [95% CI, 2.3-10.7]; P = .01), and be without baseline lung disease (absolute difference, 5.1 [95% CI, 3.0-7.2]; P < .001) or functional impairment (absolute difference, 3.3 [95% CI, 0.4-6.1]; P = .03). In adjusted multivariate models, lower education (subdistribution hazard ratio [SHR], 0.73 [95% CI, 0.57-0.94]; P = .01), Black race (SHR, 0.61 [95% CI, 0.46-0.80]; P < .001), area deprivation index national rank (SHR 1.00 [95% CI 0.99-1.00]; P = .009), and male sex (SHR, 0.73 [95% CI, 0.56-0.94]; P = .02) were associated with membership in the group without TBI. Sensitivity analyses using a broader definition of TBI yielded similar results.

Conclusions and Relevance

In this longitudinal cohort study of older adults, almost 13% experienced incident TBI during the 18-year study period. For older adults who seek care for TBI, race and ethnicity, sex, and SDOH factors may be associated with incidence of TBI, seeking medical attention for TBI in older adulthood, or both.

Long Noncoding RNA VLDLR-AS1 Levels in Serum Correlate with Combat-Related Chronic Mild Traumatic Brain Injury and Depression Symptoms in US Veterans

More than 75% of traumatic brain injuries (TBIs) are mild (mTBI) and military service members often experience repeated combat-related mTBI. The chronic comorbidities concomitant with repetitive mTBI (rmTBI) include depression, post-traumatic stress disorder or neurological dysfunction. This study sought to determine a long noncoding RNA (lncRNA) expression signature in serum samples that correlated with rmTBI years after the incidences. Serum samples were obtained from Long-Term Impact of Military-Relevant Brain-Injury Consortium Chronic Effects of Neurotrauma Consortium (LIMBIC CENC) repository, from participants unexposed to TBI or who had rmTBI. Four lncRNAs were identified as consistently present in all samples, as detected via droplet digital PCR and packaged in exosomes enriched for CNS origin. The results, using qPCR, demonstrated that the lncRNA VLDLR-AS1 levels were significantly lower among individuals with rmTBI compared to those with no lifetime TBI. ROC analysis determined an AUC of 0.74 (95% CI: 0.6124 to 0.8741; p = 0.0012). The optimal cutoff for VLDLR-AS1 was ≤153.8 ng. A secondary analysis of clinical data from LIMBIC CENC was conducted to evaluate the psychological symptom burden, and the results show that lncRNAs VLDLR-AS1 and MALAT1 are correlated with symptoms of depression. In conclusion, lncRNA VLDLR-AS1 may serve as a blood biomarker for identifying chronic rmTBI and depression in patients.

Differences in Risk of Alzheimer's Disease Following Later-Life Traumatic Brain Injury in Veteran and Civilian Populations

OBJECTIVE

To directly compare the effect of incident age 68+ traumatic brain injury (TBI) on the risk of diagnosis of clinical Alzheimer's disease (AD) in the general population of older adults, and between male veterans and nonveterans; to assess how this effect changes with time since TBI.

SETTING AND PARTICIPANTS

Community-dwelling traditional Medicare beneficiaries 68 years or older from the Health and Retirement Study (HRS).

DESIGN

Fine-Gray models combined with inverse-probability weighting were used to identify associations between incident TBI, post-TBI duration, and TBI treatment intensity, with a diagnosis of clinical AD dementia. The study included 16 829 older adults followed over the 1991-2015 period. For analyses of veteran-specific risks, 4281 veteran males and 3093 nonveteran males were identified. Analysis of veteran females was unfeasible due to the age structure of the population. Information on occurrence(s) of TBI, and onset of AD and risk-related comorbidities was constructed from individual-level HRS-linked Medicare claim records while demographic and socioeconomic risk factors were based on the survey data.

RESULTS

Later-life TBI was strongly associated with increased clinical AD risk in the full sample (pseudo-hazard ratio [HR]: 3.22; 95% confidence interval [CI]: 2.57-4.05) and in veteran/nonveteran males (HR: 5.31; CI: 3.42-7.94), especially those requiring high-intensity/duration care (HR: 1.58; CI: 1.29-1.91). Effect magnitude decreased with time following TBI (HR: 0.72: CI: 0.68-0.80).

CONCLUSION

Later-life TBI was strongly associated with increased AD risk, especially in those requiring high-intensity/duration care. Effect magnitude decreased with time following TBI. Univariate analysis showed no differences in AD risk between veterans and nonveterans, while the protective effect associated with veteran status in Fine-Gray models was largely due to differences in demographics, socioeconomics, and morbidity. Future longitudinal studies incorporating diagnostic procedures and documentation quantifying lifetime TBI events are necessary to uncover pathophysiological mediating and/or moderating mechanisms between TBI and AD.

Associations Between Sociodemographic, Mental Health, and Mild Traumatic Brain Injury Characteristics With Lifetime History of Criminal Justice Involvement in Combat Veterans and Service Members

INTRODUCTION

Veterans and service members (V/SM) may have more risk factors for arrest and felony incarceration (e.g., posttraumatic stress disorder and at-risk substance use) but also more protective factors (e.g., access to health care) to mitigate behaviors that may lead to arrest. As such, understanding which factors are associated with criminal justice involvement among V/SM could inform prevention and treatment efforts. The current study examined relationships between lifetime history of arrests and felony incarceration and sociodemographic, psychological, and brain injury characteristics factors among combat V/SM.

MATERIALS AND METHODS

The current study was a secondary data analysis from the Chronic Effects of Neurotrauma Consortium multicenter cohort study, approved by local institutional review boards at each study site. Participants were V/SM (N = 1,540) with combat exposure (19% active duty at time of enrollment) who were recruited from eight Department of Veterans Affairs and DoD medical centers and completed a baseline assessment. Participants were predominantly male (87%) and white (72%), with a mean age of 40 years (SD = 9.7). Most (81%) reported a history of at least one mild traumatic brain injury, with one-third of those experiencing three or more mild traumatic brain injuries (33%). Participants completed a self-report measure of lifetime arrest and felony incarceration history, a structured interview for all potential concussive events, the post-traumatic stress disorder checklist for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), and the Alcohol Use Disorders Identification Test-Consumption. Three groups were compared on self-reported level of lifetime history of criminal justice system involvement: (1) no history of arrest or incarceration (65%); (2) history of arrest but no felony incarceration (32%); and (3) history of felony incarceration (3%).

RESULTS

Ordinal regression analyses revealed that hazardous alcohol consumption (β = .44, P < .001; odds ratio = 1.56) was positively associated with increased criminal justice involvement after adjusting for all other variables. Being married or partnered (β = -.44, P < .001; odds ratio = 0.64) was negatively associated with decreased criminal justice involvement.

CONCLUSIONS

The rate of lifetime arrest (35%) in this V/SM sample was consistent with rates of arrests in the U.S. general population. One modifiable characteristic associated with lifetime arrest and felony incarceration was hazardous alcohol consumption. Alcohol use should be a top treatment target for V/SM at risk for arrest and those with history of criminal justice involvement.

Traumatic Brain Injury and Long-Term Risk of Stroke Among US Military Veterans

BACKGROUND

Traumatic brain injury (TBI) is associated with significant morbidity, but the association of TBI with long-term stroke risk in diverse populations remains less clear. Our objective was to examine the long-term associations of TBI with stroke and to investigate potential differences by age, sex, race and ethnicity, and time since TBI diagnosis.

METHODS

Retrospective cohort study of US military veterans aged 18+ years receiving healthcare in the Veterans Health Administration system between October 1, 2002 and September 30, 2019. Veterans with TBI were matched 1:1 to veterans without TBI on age, sex, race and ethnicity, and index date, yielding 306 796 veterans with TBI and 306 796 veterans without TBI included in the study. In primary analyses, Fine-Gray proportional hazards models adjusted for sociodemographics and medical/psychiatric comorbidities were used to estimate the association between TBI and stroke risk, accounting for the competing risk of mortality.

RESULTS

Participants were a mean age of 50 years, 9% were female, and 25% were of non-White race and ethnicity. Overall, 4.7% of veterans developed a stroke over a median follow-up of 5.2 years. Veterans with TBI had 1.69 times (95% CI, 1.64-1.73) increased risk of any stroke (ischemic or hemorrhagic) compared to veterans without TBI. This increased risk was highest in the first-year post-TBI diagnosis (hazard ratio [HR], 2.16 [95% CI, 2.03-2.29]) but remained elevated for 10+ years. Similar patterns were observed for secondary outcomes, with associations of TBI with hemorrhagic stroke (HR, 3.92 [95% CI, 3.59-4.29]) being stronger than with ischemic stroke (HR, 1.56 [95% CI, 1.52-1.61]). Veterans with both mild (HR, 1.47 [95% CI, 1.43-1.52]) and moderate/severe/penetrating injury (HR, 2.02 [95% CI, 1.96-2.09]) had increased risk of stroke compared to veterans without TBI. Associations of TBI with stroke were stronger among older compared to younger individuals (P interaction-by-age<0.001) and were weaker among Black veterans compared to other race and ethnicities (P interaction-by-race<0.001).

CONCLUSIONS

Veterans with prior TBI are at increased long-term risk for stroke, suggesting they may be an important population to target for primary stroke prevention measures.