Military Occupational Blast Exposure: Definition, Operationalization, and Validation of a Reproducible Risk Classification Metric

OBJECTIVE: To define Military Occupational Blast Exposure (MOBE) as a standardized construct of cumulative occupational blast exposure spanning low-level blast and high-level blast, and propose reproducible MOBE risk classification groups based on military occupations when objective blast records or detailed lifetime interviews are unavailable. SETTING: Data were drawn from 2 Long-term Impact of Military-relevant Brain Injury Consortium-Chronic Effects of Neurotrauma Consortium (LIMBIC-CENC) studies: a retrospective cohort study and a multisite prospective longitudinal cohort. PARTICIPANTS: The Phenotype Study included 2 522 880 post-9/11 service members and Veterans. The Prospective Longitudinal Study (PLS) included 1666 service members and Veterans who had experienced combat. DESIGN: The Phenotype Study was used to operationalize MOBE risk classification and characterize demographic and military correlates. PLS data were used to evaluate whether MOBE risk classification aligned with blast exposure history and blast traumatic brain injury (TBI) history. MAIN MEASURES: MOBE risk classification was compared with the generalized blast exposure value (GBEV) and blast exposure category scores from the Blast Exposure Threshold Survey, as well as blast TBI history from clinical interview data. RESULTS: The Phenotype study classified 31.1% of military occupational codes into high-risk MOBE (MOBE+). In the PLS, MOBE+ individuals were more likely than MOBE- individuals to report blast TBI history (43.7% vs. 27.0%) and exceed the GBEV threshold of 200 000 (66.0% vs. 42.2%; both P < .001). MOBE+ individuals also reported higher mean blast exposure scores across all categories, with significant differences for small arms and large explosives. Occupational-level analyses showed meaningful heterogeneity in blast exposure profiles across high-risk occupations. CONCLUSIONS: MOBE risk classification differentiated meaningful patterns of blast exposure and blast-related injury in a well-characterized cohort. Findings support MOBE as a practical, scalable, standardized approach for estimating occupational blast exposure risk and improving comparability across studies when detailed individual exposure histories are unavailable.