Chronic obstructive pulmonary disease (COPD) is a common lung disease. Having COPD makes it hard to breathe.
There are two main forms of COPD:
- Chronic bronchitis, which involves a long-term cough with mucus
- Emphysema, which involves damage to the lungs over time
Most people with COPD have a combination of both conditions.
Alternative Names
COPD; Chronic obstructive airways disease; Chronic obstructive lung disease; Chronic bronchitis; Emphysema; Bronchitis - chronic
Causes
Smoking is the main cause of COPD. The more a person smokes, the more likely that person will develop COPD. But some people smoke for years and never get COPD.
In rare cases, nonsmokers who lack a protein called alpha-1 antitrypsin can develop emphysema.

Other risk factors for COPD are:
- Exposure to certain gases or fumes in the workplace
- Exposure to heavy amounts of secondhand smoke and pollution
- Frequent use of a cooking fire without proper ventilation