The Millennium Cohort Study

The Millennium Cohort Study is the largest prospective health project in military history. It is designed to evaluate the long-term health effects of military service, including deployments. The Department of Defense recognized after the 1991 Gulf War that there was a need to collect more information about the long-term health of service members. The Millennium Cohort Study was designed to address that critical need, and the study was launched by 2001.

Funded by the Department of Defense, and supported by military, Department of Veterans Affairs, and civilian researchers, almost 150,000 people are already participating in this groundbreaking study. As force health protection continues to be a priority for the future of the United States military, the Millennium Cohort Study will be providing critical information towards enhancing the long-term health of future generations of military members.

Millennium Cohort Timeline

Participants include Panel 1 (enrolled beginning in 2001), Panel 2 (enrolled beginning in 2004), and Panel 3 (enrolled beginning in 2007). A Panel 4 will be invited to participate throughout the upcoming survey cycle, and we expect to have over 200,000 participants total upon completion of the cycle. Participants are asked to complete one questionnaire (by mail or online) every three years, through 2022.


The Millennium Cohort Study is a Department of Defense research project at the DoD Center for Deployment Health Research, located in San Diego, California. Note DMDC Reference Number 00-0019, RCS Number DD-HA(AR)2106, OMB Approval Number 0720-0029, ASD/HA/TMA Protocol Number CDO-06-206, and Primary IRB Protocol Number NHRC.2000.0007

About Us