When the Fuse Is Lit: Association of Military Occupational Blast Exposure With Anger, Aggression, and Violence

Military occupational blast and impulse exposure (MOBE) is a potential risk factor for increased Anger, Aggression, or Violence (AAV). The objective of this study was to assess the association between MOBE and AAV-related content in clinical text notes in Veterans Health Administration (VHA) data.

This matched cohort study investigated AAV-related content in clinical text data from Veterans across high and low-risk MOBE occupations. Veterans with documentation of high-risk MOBE occupations were sampled from a VHA population database and matched 1:1 with low-risk MOBE controls on age, sex, and race/ethnicity. An algorithm leveraging semantic similarity and large language models (LLMs) identified AAV content in millions of VHA clinical text notes. Model performance was assessed by manual review. Veteran outcomes were classified as AAV-positive or AAV-negative based on the content of their medical records. Logistic regression was used to estimate the association between MOBE and AAV.

Among the MOBE cohort (n = 5,000) and matched controls (n = 5,000), 3.64 million clinical notes (Mean: 364 notes/person) were classified using an LLM pipeline that achieved 96% classification accuracy in manual review. Raw group differences were significant, with 17.2% of the MOBE cohort meeting AAV criteria, compared to 12.0% of matched controls (unadjusted Odds Ratio [OR]: 1.53 [1.37-1.71]). In adjusted models, the association between MOBE and AAV remained significant (OR: 1.22 [1.08-1.38]). Combat exposure (OR: 1.32 [1.11-1.58]) and traumatic brain injury (TBI) (OR: 1.47 [1.29-1.67]) were associated with increased AAV, while female sex was protective (OR: 0.33 [0.24-0.45]). In nested models, the OR for AAV ranged from 1.53 to 1.16 depending on the covariates considered, and posttraumatic stress disorder (PTSD) was found to be a significant confounder of the MOBE-AAV association.

This matched cohort study found that individuals who served in occupations at high risk for MOBE were significantly more likely to have evidence of AAV in clinical text data. Neurological and affective changes potentially linked to MOBE may be interconnected with other military health factors, such as combat exposure, TBI, and PTSD.