Age is a risk factor for COPD: most people who have COPD were at least 40 years old when their symptoms began. However, the main risk factor is smoking tobacco. Most people who have COPD smoke or used to smoke cigarettes. People who have a family history of COPD (older relatives who developed it) are also more likely to develop the disease if they smoke. Long-term exposure to other lung irritants is another risk factor for COPD. These include:

Second hand-smoke from someone who is smoking tobacco in the same house every day
Industrial air pollution (smoke, chemical fumes and dust)
Most important of all in low-income countries – indoor smoke from cooking fires (Figure 4.4)

Figure 4.4 Breathing smoke from indoor cooking fires, especially when dried animal dung is used as fuel, is a risk factor for COPD. (Photo: Basiro Davey)