Association of Gulf War Illness with Characteristics in Deployed vs. Non-Deployed Gulf War Era Veterans in the Cooperative Studies Program 2006/Million Veteran Program 029 Cohort: A Cross-Sectional Analysis

Abstract

Gulf War Illness (GWI), a chronic multisymptom illness with a complex and uncertain etiology and pathophysiology, is highly prevalent among veterans deployed to the 1990-1991 GW. We examined how GWI phenotypes varied by demographic and military characteristics among GW-era veterans. Data were from the VA's Cooperative Studies Program 2006/Million Veteran Program (MVP) 029 cohort, Genomics of GWI. From June 2018 to March 2019, 109,976 MVP enrollees (out of a total of over 676,000) were contacted to participate in the 1990-1991 GW-era Survey. Of 109,976 eligible participants, 45,169 (41.1%) responded to the 2018-2019 survey, 35,902 respondents met study inclusion criteria, 13,107 deployed to the GW theater. GWI phenotypes were derived from Kansas (KS) and Centers for Disease Control and Prevention (CDC) GWI definitions: (a) KS Symptoms (KS Sym+), (b) KS GWI (met symptom criteria and without exclusionary health conditions) [KS GWI: Sym+/Dx-], (c) CDC GWI and (d) CDC GWI Severe. The prevalence of each phenotype was 67.1% KS Sym+, 21.5% KS Sym+/Dx-, 81.1% CDC GWI, and 18.6% CDC GWI severe. These findings affirm the persistent presence of GWI among GW veterans providing a foundation for further exploration of biological and environmental underpinnings of this condition.

Keywords: chronic multisymptom illness; gulf war; gulf war illness; health outcomes; post-deployment health surveys; veteran.

Figure 2

Adjusted Associations of Gulf War Illness Phenotypes with Demographic Characteristics Stratified by Deployment Status. Legend: Reference groups include male, white, non-Hispanic, ≥master’s degree, Air Force, Active Duty, and Enlisted. CDC = Centers for Disease Control and Prevention, GWI = Gulf War Illness, Kansas Sym+ = Kansas Symptoms, Kansas Sym+/Dx− = Kansas (symptoms and no exclusionary conditions), Eth = ethnicity, Branch = service branch, comp = unit component and aOR = adjusted odds ratio. Adjusted for age (as a continuous variable in the model with odds ratios calculated for 10-year increase in age), sex, race, ethnicity, education, service branch, rank, and unit component. Statistically significant if 95% confidence interval does not include 1.00 aORs are derived from eight models, two (deployed and non-deployed) for each GWI phenotype (KS Sym+, KS Sym+/Dx−, CDC GWI and CDC Severe GWI). Data are from the Department of Veterans Affairs’ (VA) Cooperative Studies Program 2006/Million Veteran Program (MVP) 029 cohort, Genomics of GWI (VA CSP 2006/MVP 029 Project) with a total study population size of 35,902; 13,107 deployed and 22,795 non-deployed.

Figure 1

Flow chart for inclusion in the analytic dataset. Legend: Data are from the Department of Veterans Affairs’ (VA) Cooperative Studies Program 2006/Million Veteran Program (MVP) 029 cohort, Genomics of GWI (VA CSP 2006/MVP 029 Project). Supplemental data are from the MVP Baseline Survey and the VA Department of Defense Identity Repository (VADIR). The source of VADIR data was from the Department of Defense (DoD) Defense Manpower Data Center and data were provided by the VA. VADIR data are used to determine eligibility for VA services.