COPD is often a mix of two diseases: chronic bronchitis and emphysema . Both of these diseases are caused by smoking. Although you can have either chronic bronchitis or emphysema, people more often have a mixture of both diseases.
Other possible causes of COPD include:
- Long-term exposure to lung irritants such as industrial dust and chemical fumes.
- Preterm birth that leads to lung damage (neonatal chronic lung disease).
- Inherited factors (genes), including alpha-1 antitrypsin deficiency. This is a rare condition in which your body may not be able to make enough of a protein (alpha-1 antitrypsin) that helps protect the lungs from damage. People who have this disorder and who smoke generally start to have symptoms of emphysema in their 30s or 40s. Those who have this disorder but don't smoke generally start to have symptoms in their 80s.