Definition of Emphysema:

Emphysema is a lung disease that involves damage to the air sacs (alveoli) in the lungs.

Causes, incidence, and risk factors:

Cigarette smoking is the most common cause of emphysema. Tobacco smoke and other pollutants are thought to cause the release of chemicals from within the lungs that damage the walls of the air sacs. This damage becomes worse over time. Persons with this disease have air sacs in the lungs that are unable to fill with fresh air. This affects the oxygen supply to the body.

A naturally occurring substance in the lungs called alpha-1 antitrypsin may protect against this damage. People with alpha-1 antitrypsin deficiency are at an increased risk for this disease.