Women who smoke cigarettes are roughly four times more likely than their ex-smoking peers and nearly nine times more likely than women who never smoked to undergo surgery for an abdominal aortic aneurysm or to experience a ruptured aneurysm, new research shows.

By contrast, diabetes was actually tied to a decreased risk of an abdominal aortic aneurysm (AAA) event. Hormone therapy, either current or past use, was also associated with a reduced risk.

An AAA occurs when the wall of the aorta - the body’s largest artery that carries blood from the heart - is stretched or weakened as it passes through the abdomen. Blood pumping through the artery can cause the weakened wall to balloon out and possibly rupture.

A ruptured AAA is an extremely dangerous event causing a massive amount of internal bleeding that is fatal without immediate surgery to repair the aorta. About 11,000 people in the United States die suddenly each year from a ruptured AAA.

“This the largest study of women to look at associations with AAA,” lead author Dr. Frank A. Lederle, from VA Medical Center, Minneapolis, told Reuters Health. “It is therefore the first to be able to confirm in women the surprising negative association of AAA with diabetes that was first described in men in the VA ADAM study.”

The findings, he added, also raise “the interesting issue of hormone therapy being protective against AAA, which could help to explain the low (rate) of AAA in women compared with men.”

The current research, reported in the journal BMJ Online First, involved 161,808 women, between 50 and 79 years of age, enrolled in the Women’s Health Initiative clinical trial or observation study. The average follow-up period was 7.8 years.

Overall, 184 women experienced an AAA rupture or repair, the report shows.

Compared with former smokers and those who never smoked, current smokers had an increased the risk of an AAA event by 4.19- and 8.73-fold, respectively. Also, for every 10-year increase in age, the risk of an event rose by 77 percent.

Conversely, diabetes was associated with a 71 percent decreased risk of an AAA event. Compared with women who never used hormone therapy, current and past use cut the odds of an event by 52 and 24 percent, respectively.

Lederle said that further studies are needed to confirm the negative association with hormone use. However, he emphasized that “we certainly don’t recommend using hormone therapy for AAA prevention,” noting that the WHI trial “showed that hormone therapy is not beneficial over the full range of important outcomes.”

“Getting women to stop smoking is a public health priority,” Dr. Janet T. Powell, from Imperial College London, and Dr. Paul E. Norman, from the University of Western Australia in Fremantle, comment in a related editorial.

“In the US, screening is in place for women with a strong family history of AAA, but if the incidence of this disorder in women in continues to rise, population screening for women who have smoked or continue to smoke might need to be considered.”

SOURCE: BMJ Online First, October 15, 2008.