Date of Award
Fall 2022
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Nursing
First Advisor
Whittemore, Robin
Abstract
Metabolic abnormalities – including overweight/obesity, glucose dysregulation and insulin resistance (IR) – are an emerging health concern in military Veterans of the United States (US) who served since the 2001 terrorist attacks (post-9/11 Veterans). There are unique risk factors for overweight/obesity in this young Veteran population, including military-service related exposures (such as blast exposure [BE] and combat trauma), changes in lifestyle after military service, and the presence of psychological (e.g., posttraumatic stress disorder [PTSD] and mood disorders) or somatic (e.g., sleep disorders and pain) conditions that can impact metabolic health overtime. The aims of this dissertation study were: 1) to understand the contributing factors to overweight/obesity in post-9/11 Veterans; 2) to synthesize the literature on long-term sequalae to BE in post-9/11 Veterans; and to 3) examine associations between BE and the development of metabolic abnormalities (overweight/obese, glucose dysregulation or IR) in the context of comorbid psychological (PTSD, mood, anxiety, and substance use disorders [SUD]) and somatic (pain and sleep disorders) conditions. The first manuscript (Chapter 2) was a scoping review of the risk factors of obesity in post-9/11 Veterans. We identified that there are unique military-service related exposures that may negatively impact metabolic health. One of these risk factors is BE, a hallmark exposure in post-9/11 Veterans. The second manuscript (Chapter 3) was a systematic review to synthesize research on the association BE and long-term functional health outcomes. In this work, we found that BE was significantly associated with increased diagnosis and severity of PTSD, some cognitive deficits, mood disorders, and auditory impairment in post 9/11 Veterans. BE is also associated with negative emotional responses, visual impairment, and poor coordination; however this evidence is limited. We identified the need for more research to determine the impact of BE on pain, sleep health and metabolic abnormalities. In the third manuscript (Chapter 4) we examined the association between BE and metabolic abnormalities (overweight/obesity, glucose dysregulation and IR) in a sample of post-9/11 Veterans and the mediating effect of psychological and somatic factors on this association. In the dissertation study, we conducted a cross-sectional, secondary data analysis of the Translational Research Center for TBI and Stress Disorders (TRACTS) longitudinal cohort’s baseline sample (N=734). Participants were included who agreed to data sharing and had at least 1 deployment to post-9/11 era conflicts. We operationalized overweight/obesity by 1) abnormal body mass index ([BMI] 25 kg/m2) vs. normal (18.5 to <25 kg/m2); 2) abnormal waist-hip-ratio ([WHR] women .85; men .90) vs. normal (women <.85; men <.90); and 3) abnormal waist circumference ([WC] women 80 cm; men 94 cm) vs. normal (women <80 cm; men <94 cm). Secondary outcomes included: 1) glucose dysregulation (hemoglobin A1C levels 5.7%); and 2) IR (homeostatic assessment of IR [HOMA-IR] 1.5; conducted with a subsample of 332 participants with available HOMA-IR data). For our primary analyses, we stratified the sample by those with BE within 100 meters (m) vs. those without BE. Secondary analyses compared outcomes in those with close blast exposure (CBE) within 10 m vs. those without CBE. We performed log-binomial regression to compute unadjusted and adjusted risk ratios (RR) and 95% confidence intervals (CI). Mediation analyses were conducted to quantify the impact of psychological and somatic conditions on the association between BE and metabolic abnormality outcomes. The sample had a mean age of 35 (SD=9.0) years, was 90.7% male, with the majority White (68.3%) and of non-Hispanic ethnicity (82%). Most participants had 1 BE <100 m (83%), with 48% experiencing 1 CBE. Most of the sample had abnormal BMI (79%), more than half had abnormal WC (60%), and half had abnormal WHR (51%). Glucose dysregulation was detected in 16% of the sample; whereas IR was detected in 32% of the sample. There was no significant association between BE and abnormal BMI, WHR, or WC in those with BE vs in those without. Similarly, there was no significant association between BE and glucose dysregulation, or IR. Exploratory analyses also found no association between CBE and metabolic abnormalities. Lastly, comorbid psychological or somatic conditions did not significantly impact the association between BE (or CBE) and metabolic abnormalities in this sample of post-9/11 Veterans. While we found no significant association between BE, CBE, and the risk of metabolic abnormalities in a large cohort of post-9/11 Veterans, Veterans in our sample had a high prevalence of abnormal BMI and central adiposity, with 16% of post-9/11 Veterans demonstrating abnormal glucose dysregulation at a young age. While more research is needed to follow Veterans longitudinally to determine long-term effects of BE, effective and sustainable weight management and metabolic health prevention interventions for this young Veteran cohort are needed.
Recommended Citation
Lendvai, Dora, "Metabolic Abnormalities in Post-9/11 Veterans of the United States and the Role of Blast Exposure, Psychological and Somatic Conditions" (2022). Yale Graduate School of Arts and Sciences Dissertations. 863.
https://elischolar.library.yale.edu/gsas_dissertations/863
