The Millennium Cohort Study: A Prospective Study of the Health of Military Service Members

Lead Contacts and/or Principal Investigators (PIs):

  • Rudolph Rull, Ph.D.
    Department of Defense (DoD) Center for Deployment Health Research, Naval Health Research Center

Funded Since: 2001
Funding Source: U.S. Department of Defense (DoD) funding via Military Operational Medicine Research Program, administered by U.S. Army Medical Research and Materiel Command; Congressionally Directed Medical Research Program by the U.S. Army; Office of Naval Research funding for specific proposals
Year(s) of Enrollment: 2001-2003, 2004-2006, 2007-2008, 2011-2013
Study Website: http://www.millenniumcohort.orgExternal Web Site Policy

This is the first large, population-based prospective study to investigate the short- and long-term health effects of military service. After the 1991 Gulf War, research on illnesses was hampered by unavailability of objective measurements on exposures at the individual level, a lack of baseline health data, and an inability to adequately control for potential confounding factors. Public health experts recommended that the Department of Defense (DoD) establish a cohort with the capability to prospectively examine health outcomes among U.S. military service members. The Millennium Cohort Study was developed to fulfill this need.

The main objectives of the study are to evaluate chronic diagnosed health problems, long-term subjective health including chronic multi-symptom illness, and various mental and physical illnesses, among military members in relation to exposures of military concern, including deployment. A stratified random sample of U.S. service members on rosters as of October 2000 (Panel 1), October 2003 (Panel 2), October 2006 (Panel 3), and October 2010 (Panel 4) were invited to participate in this longitudinal study. The questionnaire consists of more than 450 questions and assesses the health of service members at each 3-year interval, and is available in mail-in or Web-based submission choices. Currently there are more than 200,000 consenting participants and approximately 10,000 spouses who enrolled as part of the Millennium Cohort Family Study. Participants who separate from military service are encouraged to continue to participate in the study for its duration.

Data from the Millennium Cohort Study have been linked with mortality data sources, the military cancer registry, as well as military and civilian inpatient and outpatient data. Additionally, data from the study have been linked to other electronic databases to obtain deployment, demographic, vaccination, pharmacy, and separation from military service data. There is also the capability to link data from this study to the DoD Serum Repository.

Investigators and staff of the Millennium Cohort Study examine questionnaires, data collection, and analysis methods on an ongoing basis to further improve the efficiency, effectiveness, and robustness of the study. The study collaborates with individuals and organizations from all over the world for a greater knowledge base and perspective, as well as to better serve military service members around the globe. Results of this study include more than 75 published manuscriptsExternal Web Site Policy and 175 presentations that have strategically framed important health-related issues for the DoD, Veterans Administration (VA), and veterans, and have directly and indirectly impacted policy addressing the health needs of both current and separated service members.

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