Chronic obstructive pulmonary disease (COPD) is a group of lung diseases that worsen over time, especially in people who continue smoking — the leading cause of the disease. In people who have COPD, the lungs are damaged, and the passages that carry air in and out of the lungs are partially blocked, making it hard to breathe. Most people who have COPD have a combination of the two conditions that form the disease:
- Chronic bronchitis, a long-term cough with mucus, which can further block the narrowed airways
- Emphysema, the deterioration of the lungs over time, which makes it more difficult for the surface area there to exchange oxygen for carbon dioxide