Prevalence of Gulf War Illness Among Gulf War Veterans During 2001-2013

Introduction: Gulf War Illness (GWI) has been described as the signature illness of the first Gulf War (1990-1991). It is characterized by a diverse array of symptoms, including fatigue, cognitive impairment, and musculoskeletal pain. No universally effective treatment has been found for GWI, and its etiology has not been clearly defined. Methods: The first panel of the Millennium Cohort Study is a large, population-based military cohort, which has provided data at four time points between 2001 and 2013. At baseline, 9,249 deployed Gulf War veterans and 36,132 nondeployed service members from the same era (era veterans) enrolled in the Millennium Cohort Study. Items were combined to create a screening measure that approximates the Center for Disease Control’s definition of GWI. Prevalence of positive screens for GWI was compared between Gulf War and era veterans across the study period using nonlinear mixed effects modeling. Results: Adjusting the model for personal and military demographics, Gulf War veterans had a higher likelihood of screening positively for GWI than era veterans (AOR, 2.21; 95% CI, 2.03–2.40). For each year studied, era veterans were increasingly likely to screen positively for GWI (AOR, 1.18; 95% CI, 1.17–1.18). This was also true for Gulf War veterans (AOR, 1.15; 95% CI, 1.14–1.16), but there was a statistically significant interaction such that prevalence among Gulf War veterans increased at a lesser rate than era veterans. Conclusions: In 2001, Gulf War veterans were more likely to screen positively for GWI compared with era veterans. During the study period, GWI prevalence increased among era and Gulf War veterans, but prevalence increased at a lower rate among Gulf War veterans. However, Gulf War veterans still had a higher prevalence of positive screens for GWI in 2013. If changes in prevalence remain steady, Gulf War veterans will have an excess burden of GWI until approximately 2040. The size and persistence of the GWI burden among Gulf War veterans emphasizes the continued necessity for policies focused on the needs of Gulf War veterans. Future research should study potential methods for alleviating symptoms of GWI, as well as more fully determining its etiology.