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Advanced Neurology TBI and depression by veteran status

military reserve, or the National Guard. Responses were “excellent” or “very good,” with only 3.8% (n = 1,111)
either “yes” or “no.” reported their health status as “poor.” Regarding the history
of comorbidities, 37.6% (n = 11094) were reported to be
2.5. Covariates diagnosed with hypertension, followed by 6.2% (n = 1,833)

Several sociodemographic variables and chronic diseases with cardiovascular disease, 12.7% (n = 3762) with cancer,
were included as covariates in the regression model. and finally 11.2% (n = 294) of participants were diagnosed
Age was continuous and top-coded to 85+ years. Sex with diabetes. Among the participants, 18.7% (n = 5,533)
was categorized as either “male” or “female.” Race and reported to have suffered TBI at least once in their lifetime.
ethnicity were categorized into four categories – “White,” From the Pearson Chi-square test, a significant association
“African American,” “Hispanic,” and all other races into was observed between positive results in depression
the “other” category. Education was coded into “below screening and TBI across the whole sample (χ [ = 171.20,
2 1
high school,” “12 grade, GED, or equivalent,” “associate p<0.05) (Table 1).
th
degree,” “bachelor’s degree,” and finally “postgraduate
degree (Master’s/PhD/Professional).” General health was 3.2. Multiple logistic regression
categorized into five categories from poor to excellent. In our multiple logistic regression model, a statistically
Participants were asked whether, at any point in their lives, significant association was observed between TBI and
they were diagnosed with hypertension, cardiovascular depression (Table 2). When adjusted for sociodemographic
disease, cancer, and diabetes. These chronic conditions and chronic disease variables, participants with a TBI
were also adjusted for as covariates. All variables with the history had 1.80 times higher odds of depression compared
“unknown,” “refused,” or “not ascertained” entries were to participants with no brain injury record (adjusted odds
coded as missing values. ratio [aOR] = 1.80; 95% confidence interval [CI] 1.61 – 2.02,
2.6. Data analysis p<0.05).
A Chi-square test was performed to evaluate the association When stratified by veteran status, adjusting for other
between TBI and depression. For continuous variables, a covariates, veterans with a brain injury history had 2.92 times
t-test was used, and for categorical variables chi-square higher odds of depression compared to veterans without TBI
test was employed. For the multiple logistic regression, a history (aOR = 2.92; 95% CI 2.05 – 4.14, p<0.05) (Table 2).
model was constructed using the whole sample population On the other hand, non-veterans had 1.68 times higher
adjusting for sociodemographic and chronic diseases. odds of depression compared to non-veterans without TBI
Subsequently, the regression was performed again stratified history (aOR = 1.68; 95% CI 1.49 – 1.90, p<0.05).
by veteran status. When testing for multicollinearity, 4. Discussion
no individual variance inflation factor (VIF) value was
>10, and the average VIF value of all variables was 2.75, This study probed the relationship between TBI and
indicating no violation of this assumption. All the analyses depression among the whole sample as well as veterans.
in this research were conducted with two-tailed tests using In both the bivariate test and multiple regression models,
IBM Statistical Package for the Social Sciences Statistics a significant association was observed between TBI and
version 29, with p<0.05 indicating statistical significance. depression among the whole sample. In addition, it was
found that the magnitude of the TBI-depression association
3. Results was higher among veterans compared to non-veterans, with
3.1. Sample characteristics 2.9 increased odds versus 1.7 increased odds, respectively.
In comparison, a recently published meta-analysis revealed
From a total of 28,623 participants, 1,988 (6.7%) were that the odds of depression were highest at 4.1 1 to 2 years
screened as positive for depression based on the PHQ-2 after the injury, but decreased to 3.2 after 10 years of the
(Table 1). Among the study participants, 66% (n = 19,495) original injury. Interestingly, the researchers did not find
identified themselves as White, followed by 10.9% as any statistically significant difference between post-TBI
African American (n = 3,216), 15% as Hispanic (n = 4,418), depression and injury etiology. While the researchers
5
and 8.1% as others (n = 2,393). Regarding education, included studies conducted on military personnel in their
40.1% (n = 1,853) of study participants had a high school meta-analysis, no specific odds ratio for depression among
diploma or equivalent and formed the largest group in the veterans was provided.
education category. People who reported to have at least
a bachelor’s degree were the second largest group (23%, A recently published meta-analysis on depression
n = 6,792). Regarding general health, more than half of the prevalence among veterans worldwide demonstrated
participants (54%) reported their health status as either that veterans, due to their unique nature of work, sleep

Volume 4 Issue 3 (2025) 72 doi: 10.36922/AN025050008