A groundbreaking study of 1,946 male veterans of World War II and Korea suggests that vets with symptoms of post-traumatic stress disorder are at greater risk of heart attacks as they age.

The new study is the first to document a link between PTSD symptoms and future heart disease, and joins existing evidence that vets with PTSD also have more autoimmune diseases such as arthritis and psoriasis.

A second study, funded by the Army, found that soldiers returning from combat in Iraq with post-traumatic stress disorder reported worse physical health, more doctor visits and more missed workdays.

The Army study is based on a survey of 2,863 soldiers one year after combat. Their study was funded by the National Institutes of Health and the Department of Veterans Affairs. The Army study appears in the American Journal of Psychiatry. Medical authorities first accepted post-traumatic stress disorder as a psychiatric condition in 1980 at the urging of Vietnam veterans.

In PTSD, the body's normal hormonal response to stress becomes trigger-happy, scientists believe. Long after traumatic events, people remain edgy, fearful and prone to nightmares and flashbacks. The continual release of adrenaline may wear down the cardiovascular system.

The Harvard and Boston University researchers analyzed data from the Veterans Administration Normative Aging Study, a long-term research project tracking Boston-area vets.