Profile of two cohorts: UK and US prospective studies of military health

In the United Kingdom and United States, these two independent cohort studies have been instituted to prospectively study the health of service personnel and veterans. From comparisons with baseline information, these studies are designed to better inform the military and the public on how best to protect the health of their armed forces and better understand the long-term risks of some occupational exposures that extend beyond military communities. In order to do this, these studies consider: 1) The underlying physical and mental health of the military populations before, during, and after military service; and 2) The specific effects of deployment, deployment-related exposures, and other occupational exposures upon personnel compared with unexposed subgroups. Whilst previous studies have attempted to address these topics, they have often been limited in their generalisability to all service branches and components of the military, or previous population-based methodologies have been largely limited to cross-sectional or retrospective methods. Although follow-up to the National Vietnam Veterans Readjustment Survey, called the National Vietnam Veterans Longitudinal Study, is still ongoing, this study is focused on a single deployment. Similarly, the Air Force Health study, a 20-year longitudinal study of approximately 20,000 Vietnam veterans, assessed potential health effects associated with exposure to aerial spraying of dioxins. Here, we present two prospective, longitudinal, multi-service studies of active duty and Reserve/National Guard personnel that will continue to follow participants even after they have left military service. We describe these two studies in detail, comparing study populations, methodology, and the published literature so far. Potential areas for future collaboration are also explored. By understanding the inherent similarities and differences between these two cohorts and leveraging each study?s unique strengths and strategies to minimize