Chronic bronchitis is a form of chronic obstructive pulmonary disease (COPD) caused by chronic inflammation of the bronchi -- the airways leading from the trachea to the lungs.
In contrast to acute bronchitis (a temporary condition related to a viral infection or environmental exposures), chronic bronchitis is a serious disease involving permanent damage to the airways.
Chronic bronchitis involves a cough that produces sputum that is present daily for 3 months in a row, with those periods occurring at least 2 consecutive years. The most common cause is smoking, but exposure to secondhand smoke, air pollution, and on-the-job chemicals may also cause chronic bronchitis.
Chronic bronchitis increases the risk of lung infections, and may also raise your risk of developing lung cancer.
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