Former National Football League players are more likely to have enlarged aortas, which may increase their risk of deadly aneurysms, says a new study.

The aorta is the largest artery in the body, and it carries blood from the left ventricle, the heart's main pumping chamber, to the rest of the body. The short section that rises from the left ventricle and supplies the coronary arteries with blood is called the ascending aorta.

Enlargement, or dilation, of the ascending aorta can increase the chances of a life-threatening aneurysm. Risk factors for dilation include high blood pressure and smoking.

"Patients whose ascending aortas are more than 4 centimeters in diameter are generally considered to have dilation, which can progress over time and potentially weaken the wall of the aorta," said study author Christopher Maroules, M.D., formerly of the University of Texas Southwestern Medical Center in Dallas and current chief of cardiothoracic imaging at the Naval Medical Center in Portsmouth, Va.

For the study, Dr. Maroules and colleagues evaluated whether past participation in the NFL is associated with increased frequency of ascending aortic dilation.

They compared 206 former NFL athletes with 759 men from the Dallas Heart Study who were older than age 40 with a body mass index greater than 20.

Data was obtained using cardiac gated non-contrast CT, a technique that allowed them to "freeze" the motion of the heart by synchronizing the CT to the electrocardiogram. They also obtained coronary artery calcium scores, a measure of atherosclerotic plaque.

Compared to the control group, former NFL athletes had significantly larger ascending aortic diameters.

Almost 30 percent of the former NFL players had an aorta wider than 4 centimeters, compared with only 8.6 percent of the non-players. Even after adjusting for age, body mass and cardiac risk factors, former NFL players were still twice as likely as the control group to have an aorta wider than 4 centimeters.

"In former NFL athletes, there was a significantly higher proportion of aortic dilation compared to our control group," said Maroules, who said the condition was probably not linked to atherosclerosis because they didn't find any significant differences in amounts of coronary artery calcium.

The results suggest that some type of remodeling process occurs in the aorta of athletes who engage in repeated strenuous exercise, according to Maroules, but it's unknown if the remodeling causes problems for athletes as they age.