Causes of Chronic Obstructive Pulmonary Disease
Smoking tobacco causes 80 to 90 percent of COPD cases. An agent in tobacco smoke stimulates inflammation in the lungs, leading to destruction of the alveoli and narrowing of the airways. While smoking is related to most cases of emphysema, only 15 to 20 percent of smokers develop the disease. What other factors contribute to the development of "smokers emphysema" remains unclear.
Familial emphysema, or alpha1-antitrypsin (AAT) deficiency-related emphysema, is caused by the hereditary deficiency of a protein called alpha1-antitrypsin. This deficiency leads to uncontrolled destruction of the alveoli and emphysema.
Occupational exposure to dust, fumes, and gases appears to contribute slightly to lung function decline and chronic bronchitis. The role of air pollution in COPD remains controversial.