All-Cause Mortality and 1990-1991 Gulf War Service within the Millennium Cohort Study (2001-2021).

Although 1990-1991 Gulf War deployment has been linked to worse health outcomes such as chronic multisymptom illness (CMI), often referred to as Gulf War Illness, among deployed Gulf War Veterans, less is known regarding Gulf War service and mortality. Using 20 years of longitudinal data from Gulf War Veteran and Era personnel from the Millennium Cohort Study (2001-2021; n=45381), Cox proportional hazard models estimated the relative effects of Gulf War service status, CMI, and their corresponding interaction on all-cause mortality. Although age- and sex-adjusted mortality ratios suggested that Gulf War Veterans had higher mortality rates than Era personnel, no association was observed between Gulf War service status and mortality risk. Screening positive for CMI was associated with greater risk of all-cause mortality compared with those who did not screen positive across both GWV and Era personnel; interactions between CMI and Gulf War status were not statistically significant. This finding suggests that CMI increases mortality risk regardless of whether the symptomology is associated with Gulf War deployment. Future research is necessary to examine specific occupational and environmental exposures experienced during deployments and service in support of the 1990-1991 Gulf War and their association with mortality in this population.