In the United States of America 70% of COPD is due to smoking, 30% is due to previous lung infections or recurring asthma attacks that damage the lung tissue or genetic abnormalities like Alph-1 antitrypsin deficiency. Even smoking-related COPD tends to run in families, suggesting a genetic link.
COPD results in damage to the lungs over many years. It affects both men and women. The average age is 60 years old. However, COPD can be diagnosed in patients in there 30s and 40s.
Smoking is the main cause of COPD. Only 10-15% of heavy smokers will develop COPD. It is still unknown why. COPD can also result from occupational exposure to chemical dust, fumes and organic dust such as grain, cotton, wood or mining dust.
COPD is caused by indoor and outdoor air pollution such as heavy concentrations of mold, dust mites and allergens in peoples home. Outdoor pollution such as emissions from cars, heavy traffic and factory emissions can also be a cause.
COPD is more likely in people who as children developed distress symptoms from viral or bacterial infections.