Long-term mortality amongst Gulf War Veterans: is there a relationship with experiences during deployment and subsequent morbidity?

BACKGROUND: Gulf War Veterans have previously been shown to have, in the short-term, an excess risk of death from 'external' (i.e. non-disease) causes of death. This study aims to determine whether there remains an excess of non-disease-related deaths in Gulf Veterans, 13 years after deployment, and, for the first time, to determine whether there is a relationship between experiences reported in the Gulf, post-war symptoms, and subsequent mortality experience. METHODS: We conducted a cohort study with follow-up from April 1, 1991 (the end of the Gulf War) to June 30, 2004. Participants were 53 462 Gulf War Veterans and a cohort of military personnel, matched for age-group, sex, rank, service and level of fitness, who were not deployed to the Gulf. The outcome measure used was mortality as recorded on the NHS central register. RESULTS: There is no difference, 13 years after the end of the Gulf War, in the overall mortality experience of Gulf War Veterans. The excess in non-disease-related deaths previously reported is confined to the initial 7 years of follow-up [mortality rate ratio (MRR) 1.31, 95% confidence interval (CI) 1.06-1.63] rather than the more recent period (MRR 1.05, 95% CI 0.83-1.33). Overall experiences reported during Gulf deployment did not influence subsequent risk of dying, but there was non-significant increased risk of dying from a disease-related death (MRR 1.99, 95% CI 0.98-4.04) associated with reported exposure to depleted uranium and of a non-disease-related death associated with reporting handling of pesticides (MRR 2.05, 95% CI 0.91-4.61). Reporting of morbidity in the health surveys conducted was not related to future risk of death. CONCLUSION: The higher rates of non-disease-related deaths in Gulf War Veterans is not evident in the period of follow-up since 1997. Neither the excess morbidity reported in health surveys nor the experiences during deployment significantly influenced future mortality. The two non-significant associations found (reported depleted uranium exposure and disease death, reporting handling pesticides and non-disease deaths) need to be considered in the context of the number of possible associations examined and potential biases-although they are biologically plausible.