FRIDAY, March 3, 2006 (HealthDay News) -- Military veterans exposed to combat have a higher long-term risk of heart attacks and strokes than either non-vets or vets not exposed to combat, researchers report.
"Their risk of heart disease is predicted to be higher," said study author Anna Johnson, a doctoral candidate at the University of North Carolina, Chapel Hill.
Johnson found that, compared to non-veterans, combat veterans' 10-year risk of heart disease is more than 3 percentage points higher.
She presented the findings Friday at the American Heart Association (AHA) annual conference on Cardiovascular Disease, Epidemiology and Prevention, in Phoenix.
In the study, Johnson and her colleagues followed nearly 5,000 men, including veterans who saw combat, veterans who didn't, and non-veterans who served as controls. "They came in for visits every few years," she said, "with about four visits each since the 1980s."
Researchers looked at measures such as blood pressure, smoking, cholesterol levels and other factors to predict their heart disease risk over the next decade. The men started the study between 1987 and 1989, and the last follow-up questionnaires were conducted in 2001 and 2002.
Johnson's team found that the mean predicted 10-year risk of heart disease risk was 10.2 percent for the non-veterans, 11.5 percent for the veterans not exposed to combat and 13.3 percent for those exposed to combat.
While others have studied veterans and their risk of combat, she said "nobody has looked at predicted risk." And many previous studies did not separate subjects who were in combat from those who were not, she said.
The follow-up time is also longer than in most studies, Johnson noted. "Other studies have looked at shorter-term risk and found limited evidence for a higher risk of cardiovascular events."
"I was surprised there was such marked effects," she said.
Deciphering how combat boosts heart risk is beyond the scope of her study, Johnson said. "Is it behavioral? Are they all smoking and not exercising? Is it psychological? I don't know the underlying mechanisms."
In a previous study, which Johnson presented last year at another AHA conference, she found that veterans of World War II, Korea and Vietnam who had seen combat were 60 percent more likely to be heavy drinkers than those who had not, and four times as likely to be problem drinkers than those who hadn't been in the armed forces at all.
She also found that combat vets were 20 percent more likely to be heavy smokers than vets who hadn't seen combat, and nearly two times as likely to smoke heavily compared with non-vets.
Joseph Boscarino, a Vietnam veteran and senior investigator for the Giesinger Clinic in Danville, Pa., has researched combat exposure and post-traumatic stress disorder (PTSD) for 30 years. He said this new study "adds to the growing literature that combat is related" to heart disease.
But he added an interesting observation, based on his research. "We found combat by itself is not significant when you control for PTSD."
PTSD is a psychiatric condition triggered by a life-threatening event such as military combat, disaster or serious accident. People with PTSD often suffer from nightmares, flashbacks and other persistent reminders of a past traumatic event.
In other words, Boscarino said, "combat by itself doesn't make you more at risk for heart disease, it is whether you develop PTSD. It appears that PTSD is a good predictor of heart disease risk."
For more on stress and heart disease, head to the American Heart Association.