Asthma May Raise Risk of COPD, Emphysema
Asthma Patients May Be Up to 17 Times More Likely to Develop Incurable Lung Diseases
July 12, 2004 -- Adults with asthma may face dramatically
higher risks of developing potentially deadly lung diseases later in life,
according to a new study.
Researchers found asthmatic people were 12 times more likely to
be diagnosed with chronic obstructive pulmonary disease (COPD) than people
COPD is a group of lung diseases for which there is no cure.
COPD causes permanent damage to the lungs, making it difficult to breathe. It
includes emphysema and chronic bronchitis.
According to the National Heart, Lung, and Blood Institute, it
is the fourth leading cause of death in the U.S. and the
"Our study shows a strong link between asthma diagnosis and
the development of COPD, which suggests they may share a common
background," says researcher Graciela E. Silva, MPH, of the University of
Arizona's College of Medicine in Tucson, in a news release. "It is possible
that factors such as smoking and repeated episodes of acute bronchitis may
facilitate the evolution of asthma into COPD, but the process by which asthma
and COPD become comorbid conditions is not clear."
Asthma Linked to Increased COPD Risk
In the study, published in the July issue of Chest,
researchers tracked a group of about 3,000 people who enrolled in the Tucson
Epidemiologic Study of Airway Obstructive Disease from 1972 to 1973. The
participants were evaluated at the start of the study for asthma and other
health conditions -- such as allergies and smoking status -- and then followed
for 20 years.
Researchers found that people with active asthma had a
significantly higher risk of chronic lung diseases later in life. Compared to
adults without asthma, adults with asthma were:
- 17 times more likely to be diagnosed with emphysema
- 10 times more likely to develop symptoms of chronic bronchitis
- 12.5 times more likely to develop COPD
Smoking and advanced age also significantly increased the risk
of being diagnosed with COPD or another chronic lung disease.
"Although most people living with COPD have a history of
smoking, the majority of smokers do not develop COPD later in life, suggesting
that other factors, such as genetic, occupational, or environmental conditions,
convey significant risks," says Silva.
Researchers say that for people with asthma, minimizing
exposure to risk factors like tobacco smoke and air pollution may delay or help
prevent the development of COPD. Using effective anti-inflammatory therapy at
the start of asthma symptoms may also decrease the likelihood of COPD
developing years later.
No increase in risk of chronic lung disease was found in people
who had a diagnosis of asthma but were no longer experiencing symptoms.
"Although there is no cure for COPD, early detection is
critical in slowing disease progression," says Richard S. Irwin, MD,
president of the American College of Chest Physicians, in the release.
"Understanding the relationship between COPD and other chronic lung
diseases, such as asthma, may lead to early disease detection, as well as more
effective treatments for patients with COPD."