 - Researchers at the National Cancer Institute and the Department of Defense are trying to learn more about what causes cancer, heart disease, and other health problems. To do this, they gather data on risk factors and biological markers. They get these data from large groups of people in long-running studies. As these groups of people age, researchers must form new groups. TRICARE is a health insurance program for uniformed service members and their families. It is a major part of the Military Health System. Researchers hope to form a new study group from TRICARE members. This study will test if TRICARE members will take part in a research study. 