Asthma May Raise Risk for Abdominal Aneurysm
main artery, the aorta, where it passes through the
abdomen. That weak spot can rupture, causing massive
bleeding. The researchers also found that people with recent
asthma activity were more likely to have an aneurysm rupture
compared to those without recent asthma activity.
"People with abdominal aortic aneurysm who were diagnosed
with asthma within the past year had more than a 50
percent greater risk of ruptured aneurysms than those
without asthma," said lead researcher Guo-Ping Shi, from
Brigham and Women's Hospital in Boston.
Men diagnosed with asthma within the preceding six months
were twice as likely to have an aortic aneurysm rupture, Shi
said, adding that the risk was much lower among women.
The researchers also found that use of anti-asthmatic
medication in the last six months was linked to a 45 percent
raised risk of an abdominal aortic aneurysm.
Shi cautioned that the study only shows an association
between asthma, aneurysm and rupture; it doesn't prove that
asthma causes aneurysm or the rupture of an aneurysm.
The study was published online Feb. 11 in the journal
Arteriosclerosis, Thrombosis and Vascular Biology.
Abdominal aortic aneurysm is more likely to occur in older men
who have other risk factors, such as smoking, high blood
pressure, high cholesterol, obesity and emphysema, Shi said.
The aorta carries blood to the whole body. When it becomes
weakened it can form a balloon-like bulge that may rupture,
he said. Because an abdominal aortic aneurysm rupture can
be deadly, Shi recommended that men 50 and older with
asthma be checked for aneurysms.
This can be done with a noninvasive ultrasound. And, if
necessary, an aneurysm can be fixed with an operation, Shi
said.
According to Dr. Len Horovitz, a pulmonologist at Lenox Hill
Hospital in New York City, "If you have asthma and doubts
about whether you have an aneurysm, you can have an
abdominal ultrasound. It's easy and noninvasive."
For the study, Shi and his colleagues collected data from two
national health registries in Denmark. One had information on
nearly 16,000 men and women aged 50 and older. About
4,500 of the adults in this group had an abdominal aortic
aneurysm, the study said. The second registry had information
on 619 people with abdominal aortic aneurysm, along with
information on smoking status.
Shi said the most likely culprit behind the association is a
specific inflammation-related protein called IgE, or
immunoglobulin E, which the body makes in response to
allergens.
IgE makes arteries stiff, which can lead to aneurysm, Shi
said. If IgE is the culprit, the risk for an aneurysm wouldn't
be confined to asthma, but would include allergies and other
allergic diseases, too, because these conditions cause levels of
IgE to increase.
The connection between asthma and aneurysm was first seen
in animal studies. Mice with asthma developed aortic aneurysms
twice as large as those without the disease, Shi said.
Dr. Gregg Fonarow, a professor of cardiovascular medicine
and science at the University of California, Los Angeles, said,
"Asthma involves inflammatory mechanisms, including mast cells
and IgE, and effective treatment of asthma has long involved
therapies that target inflammation."
Recent studies have found that mast cells and IgE can be
found in abdominal aortic aneurysms, he said.
"This study provides additional evidence suggesting that
inflammation is playing a role in abdominal aortic aneurysms
and it may open new lines of research into potential
therapies to prevent the development and rupture of
abdominal aortic aneurysms," Fonarow said.
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