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Chronic Obstructive Pulmonary Disease: Overview and Risk Factors

Chronic obstructive pulmonary disease (COPD) is a progressive and irreversible airway disorder usually caused by smoking. It is characterized by diminished inspiratory and expiratory lung capacity, airflow obstruction, and impaired gas exchange. COPD is the fourth most common cause of death in the United States and the sixth most common cause of death worldwide. Its incidence and mortality rate are on the rise, due to increasing worldwide cigarette use and air pollution.

COPD pathophysiology involves chronic bronchitis and emphysema. Chronic bronchitis is characterized by airway inflammation and defined by the presence of a productive cough that lasts at least 3 months and occurs in more than 2 successive years. Emphysema entails enlargement of air spaces and destruction of the lung parenchyma, resulting in closure of small airways and loss of lung elasticity.

Risk Factors

Smoking. Cigarette smoking is the most important risk factor for COPD, and it accounts for more than 90% of cases. Secondhand smoke also contributes to COPD.

Occupation.  A number of occupational pollutants, especially aerosol sprays and fine airborne particulates, have been linked to an increased incidence of COPD.

Air pollution. The role of pollutants in the pathogenesis of COPD is unclear. However, the incidence of COPD and the frequency of acute exacerbations are significantly increased in heavily polluted areas.

Genetics. There is a clear genetic predisposition toward the development of COPD, although specific genes have yet to be identified.

a1-antitrypsin deficiency. a1-antitrypsin is an inhibitor of the elastase enzyme. This disorder predisposes a person to emphysema due to the uncontrolled action of elastase, which destroys the lung parenchyma.

Chronic Obstructive Pulmonary Disease: Diagnosis and Treatment >>