Definition of Chronic bronchitis:

Chronic bronchitis is an inflammation of the main airways in the lungs that continues for a long period or keeps coming back.

Causes, incidence, and risk factors:

Cigarette smoking is the main cause of chronic bronchitis. The more a person smokes, the more likely it becomes that the person will get bronchitis and that the bronchitis will be severe.

Secondhand smoke may also cause chronic bronchitis. Air pollution, infection, and allergies make chronic bronchitis worse.

Chronic bronchitis is one form of chronic obstructive pulmonary (lung) disease. Chronic bronchitis, emphysema, and asthma as a group are a leading cause of death in the United States.