New health study spans 21 years

DoD, VA partner to evaluate health of troops throughout careers

WASHINGTON, November 9, 2000 (GulfLINK) - The departments of Defense and Veterans Affairs are preparing to study the health of 140,000 servicemembers, throughout their military careers and after they leave the service. Known as the "Millennium Cohort Study," the research project is designed to evaluate the impact of military deployments on various measures of health over time, including medically unexplained symptoms and chronic diseases such as cancer, heart disease and diabetes.

Led by principal investigators Navy Capt. Greg Gray, M.D., M.P.H., and Ed Boyko, M.D., the study's team includes scientists from the Army, Navy and Air Force. The Scientific Steering and Advisory Committee also includes five external scientists and three representatives of the larger veterans service organizations.

"We are excited to be conducting this ambitious study," said Captain Gray, U.S. Navy director at the DoD center for deployment health research in San Diego, Calif. "We also very much appreciate the assistance of consultants from several veteran service organizations who have helped us with the design of the questionnaire and study.

"We have worked closely with experts from a number of universities and the Department of Veterans Affairs in designing a study which will help us understand the impact of military service upon healthy young men and women so that we may better care for them and their colleagues in the future," added Gray.

One of the many lessons of the Gulf War is that the lack of ongoing, population-based longitudinal health studies has limited the ability to identify deployment-related health outcomes. When researchers want to learn whether a medical condition is occurring at a higher-than-expected rate among veterans of a particular conflict, it can be quite difficult to determine what the "expected" incidence of that ailment really is.

"There may be a great deal of information available about how the condition occurs within the general population: how many people per 100,000 come down with it each year, the average age of onset, whether it occurs more often in some parts of the country than in others and so forth," says Michael Kilpatrick, M.D., deputy director for medical readiness in the special assistant's office for Gulf War illnesses, medical readiness and military deployments. "But a military population can be considered unique because of factors such as age spread, living conditions, physical fitness levels and the different hazards to which its populations are exposed. For these and other reasons, health comparisons between military and general populations do not always yield the best possible information."

The Millennium Cohort Study is designed to identify and follow health outcomes in future U.S. military cohorts beginning in the year 2001. In the study, investigators intend to adapt and coordinate the numerous dynamic medical information systems that are currently being developed. This should ensure that future investigators will not have to rely as much as they currently do on special investigative studies to determine the effects on health of military deployments. The cohort study is to serve as a foundation upon which other routinely captured medical and deployment data can be added to answer future questions about the health risks of military deployment, military occupations, and general military service.

The basic design of the Millennium Cohort Study was recommended by the Institute of Medicine report, "The Gulf War Veterans: Measuring Health." The study will initially be a cross-sectional sample of 100,000 U.S. military personnel - as of October 2000 - composed of 30,000 veterans who have been recently deployed to Southwest Asia, Bosnia or Kosovo, and 70,000 veterans who have not been deployed to these conflicts.

In October 2004 and October 2007, 20,000 new military personnel will be added to the study population. The total of 140,000 veterans will be followed until the year 2022. The active-duty personnel initially selected will be divided between those who are currently deployed and those who have not deployed. Active-duty personnel will make up 60 percent and National Guard and Reserve personnel about 40 percent of the study population. Women will comprise about 30 percent of the population surveyed.

The survey questionnaire will include questions on demographic characteristics, self-reported medical conditions and symptoms, health-related behaviors and self-assessed physical and mental well-being. Computerized health data from DoD and the VA will augment survey data on health outcomes. All data provided by individuals will be confidential, protected by law from release to any outside agencies. Data will be reported anonymously and will be grouped by variables that include age, sex, military occupational specialty, deployment areas and frequency of deployment.

"One thing military researchers have not had in the past, which will be developed through the cohort study, is a profile of the 'normal' soldier," continued Kilpatrick. "This study will be of enormous benefit to investigators in the future as they study the possible hazards of individual deployments."