PROJECT SUMMARY Over 44% of post 9/11 veterans, those who served in Iraq and Afghanistan and receive healthcare through the Veterans Health Administration, are obese (BMI>30). This obesity rate exceeds what is observed in the general public, and questions remain as to why this phenomenon occurs. Obesity is an independent risk factor for more serious metabolic abnormalities, and can lead to glucose dysregulation, insulin resistance (IR) and type 2 diabetes. While the risk for obesity in post 9/11 veterans is complex, military service injuries (such as traumatic brain injuries [TBIs]), post-military psychological disorders (e.g.; post-traumatic stress disorder [PTSD], depressive, anxiety and substance use disorders [SUD]) and somatic sequalae (sleep disturbance and pain) have been suggested as unique predictors of obesity in this veteran cohort. Recent evidence also suggests that damages sustained from exposure to repeated, and often close-range blast explosions during deployment to post 9/11 military conflicts may also impact metabolic health. Therefore, the purpose of this project is: (1) to identify associations between military blast exposures (experience of any blasts within 100m vs. no blast during military service) and metabolic abnormalities (obesity, glucose dysregulation and IR); and (2) to examine the mediating effect of psychological (PTSD, depressive, anxiety and substance use disorders) and somatic factors (sleep disturbance and pain) on metabolic abnormalities in a sample of post 9/11 veterans. Using the Translational Research Center for TBI and Stress Disorders (TRACTS) ongoing longitudinal cohort’s baseline sample (n=573) and a conceptual framework derived from a systematic review of the literature, we will conduct a cross-sectional, secondary data analysis to complete the study aims. We will use validated questionnaires and clinical data collected from TRACTS participants and conduct univariate, bivariate and logistic regression analyses, as well as a series of mediation analyses using the counterfactual approach. The proposed training plan includes rigorous quantitative skills development, scholarly work, team collaboration and other activities to provide a strong foundation in nursing research methods to support this study with post 9/11 veterans. The expected outcomes of this project include better understanding the impact of military blast exposure on key metabolic abnormalities in post 9/11 veterans and the post-military psycho-somatic factors that affect the strength of these relationships. Results of this study will provide important clinical implications for the prevention and treatment of metabolic abnormalities, especially obesity, glucose dysregulation and IR in post 9/11 veterans.