Objective: Chronic multisymptom illness/Gulf War illness (CMI/GWI) is the defining illness of the 1990 to 1991 Gulf War. However, few studies have examined changes over time in CMI/GWI prevalence.
Methods: Prevalence of CMI/GWI over time was compared between three groups of military personnel (9110 Gulf War veterans, 36,019 era personnel, 31,446 non-era personnel) enrolled in the Millennium Cohort Study. Post hoc analyses were conducted among participants with no reported mental and physical health conditions (N = 30,093).
Results: CMI/GWI prevalence increased substantially over the study period among all groups. Gulf War veterans had the highest prevalence of CMI/GWI across the study period. This finding persisted after excluding participants with mental and physical health conditions.
Conclusions: Gulf War veterans' increased risk of CMI/GWI persisted across the study period, highlighting the continued importance of screening and improving treatment options among this population.