MONDAY, April 4 (HealthDay News) -- Male sex hormones may explain why men are four times more likely than women to develop abdominal aortic aneurysms, researchers say.

Abdominal aortic aneurysms are dangerous ruptures in the main artery carrying blood from the heart to the lower body. These aneurysms are estimated to be the main cause of death in 4 percent of people over age 65 in the United States. For reasons that have remained unclear, men are much more likely than women to die from abdominal aortic aneurysms.

This new study may help clear up that mystery. In their research, a team at the University of Kentucky found that by removing circulating male sex hormones -- including testosterone -- from male mice, they reduced the rodents' level of aneurysm to that seen in female mice.

On the other hand, giving female mice those same male sex hormones increased their aneurysm risk to the level of males.

The researchers plan to do more research to try to identify possible targets for the development of drugs to reduce the incidence of aneurysms. Currently, there are no drugs to treat aneurysms. Surgery can help, but is only performed when the risk of death due to possible rupture of the aneurysm outweighs the risk of surgery.

The study was presented April 4 at the Experimental Biology meeting in San Diego.

More information

The Society for Vascular Surgery has more about aortic aneurysms.