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What is chronic obstructive pulmonary disease (COPD)?

Chronic obstructive pulmonary disease (COPD) refers to a group of lung diseases that can interfere with normal breathing.


The causes of COPD are not fully understood, but the most prevalent risk factor of COPD is smoking. Nearly 80 percent of COPD deaths are caused by smoking. Other causes, such as air pollution and occupational exposures, may play a role, especially when combined with smoking. Heredity may also be a factor in some patients' emphysema and is important in a rare form due to alpha 1 anti-trypsin deficiency.

How common is it?

Nearly 13 million Americans suffer from COPD, according to the American Lung Association, and 24 million U.S. adults have evidence of impaired lung function, indicating an under diagnosis of COPD. COPD is also the third leading cause of death in the U.S.


The two most common conditions of COPD are chronic bronchitis and emphysema.

  • Patients with chronic bronchitis usually have a cough and sputum production for many years before they develop shortness of breath. 
  • Patients with emphysema usually have shortness of breath and develop a cough and sputum during a respiratory infection, or in the later stages of the illness.
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