Smoking heightens aortic rupture risk for women
■ Abdominal aortic aneurysms are more common in older male smokers but perhaps more deadly for women, a study reported.
By Susan J. Landers — Posted Nov. 24, 2008
Washington -- Add another strong incentive to the list of reasons for women smokers to quit: abdominal aortic aneurysms.
A study posted online Oct. 14 in the British Medical Journal found that women who smoke were four times more likely to have an abdominal aortic aneurysm repair or rupture than women who had stopped. Women smokers also were eight times more likely to have the serious medical emergency occur than were women who had never smoked.
Most studies of AAA have focused on men. This study is believed to be the largest conducted on women.
"We've known that smoking confers a very high risk of AAA," said the study's lead author, Frank Lederle, MD, professor of medicine at the University of Minnesota and an internist at the Minneapolis VA Medical Center. The study's aim was to reach a better understanding of factors associated with AAA in women, the authors write.
"This study does provide another reason to quit smoking," he said.
The ballooning of the artery wall is more common in men older than 60 but may be more deadly for women, possibly rupturing at a smaller diameter. Aortic aneurysms cause about 15,000 deaths a year in the United States, with most originating in the abdomen. About 40% of the deaths occur in women.
"Women may not be getting the attention they should, especially women with a family history for AAA and who are smokers. They should be considered for screening," said David Neschis, MD, a vascular surgeon and associate professor of surgery at the University of Maryland's School of Medicine. Dr. Neschis was not involved with the study.
AAA has a high risk of mortality. Only a small number of people make it to the hospital alive, and those who do have about a 50-50 chance of death, Dr. Neschis said. "So the best way to treat these patients is to identify them before rupture and fix them." The bulging arteries are difficult to detect in a physical exam, so ultrasound scans of the abdomen are recommended.
"A screening ultrasound of the belly takes minutes, has no risk, is inexpensive in medical terms and is available at even the smallest community hospital," Dr. Neschis said.
The Agency for Healthcare Research and Quality recommends against routine screening in women but does recommend a one-time screening for men ages 65 to 75 who have ever smoked.
Reinforcing old warnings
The study's authors used data collected on 161,808 postmenopausal women enrolled in the Women's Health Initiative, a clinical trial that studied the effects of estrogen therapy, diet and vitamin D on heart disease, fractures, breast and cervical cancer. The main study ended in 2005.
During 7.8 years of follow-up, Dr. Lederle and colleagues found that 184 abdominal aneurysm repairs or ruptures were reported. The AAA's were strongly linked to age and smoking. Women in their late 60s were more likely to have been affected than were younger women.
The principal messages for physicians are not new, said Janet Powell, MD, PhD, a professor of vascular surgery at the Imperial College in London and an author of an accompanying editorial. "More efforts must be made to stop women from smoking, and AAA must be high on the list of differential diagnoses in older women smokers who present with collapse and abdominal or back pain."
The connection between smoking and the entire world of heart disease isn't a surprise, said Vincent Bufalino, MD, an American Heart Assn. spokesman and president and CEO of Midwest Heart Specialists in Naperville, Ill. "Of the women I see with heart disease, far and away the majority are smokers. Either diabetes or smoking are the two biggest predictors of coronary heart disease."
Joel Dunnington, MD, a consultant on smoking issues for the Texas Medical Assn., would like physicians to counsel patients about the many risks of smoking, including AAA. And patients should be told that if they quit smoking at age 40, 50 or even 60, their risk levels quickly decline, he said. Dr. Dunnington is also an associate professor of radiology at the M.D. Anderson Cancer Center at the University of Texas in Houston.
The study also turned up a couple of other findings, Dr. Lederle said. For example, it was determined that hormone therapy provided protection from AAA events. This conclusion was in contrast to previous smaller studies, which found that estrogen alone may increase risk.
"That was a surprise," Dr. Lederle said. "It hadn't been shown before and needs to be confirmed. We certainly aren't suggesting that people go out and take hormones, but it does suggest there is a role for female hormones in providing protection from AAA, which might explain why there are fewer in women."
In another finding, diabetes also conveyed protection to women. Although this has been seen in previous studies among men, whether it occurred among women had been uncertain, the researchers write. But why this negative association occurs has yet to be explained.