lung and airway disorders
Chronic Obstructive Pulmonary Disease (COPD)
Causes of COPD
Themost importantcause of COPD is Cigarette smoking Only about 15% of smokers develop COPD. With aging, susceptible cigarette smokers lose lung function more rapidly than nonsmokers. Lung function improves only a little if people stop smoking. However, the rate of decline of lung function returns to that of nonsmokers when people stop smoking, thus delaying development and progression of symptoms. Pipe and cigar smokers develop COPD more often than nonsmokers but not as often as cigarette smokers. It is not clear whether smoking marijuana contributes to COPD. Working in an environment polluted by chemical fumes or dust or by heavy smoke from indoor cooking fires may increase the risk of COPD (see Overview of Environmental and Occupational Lung Disease ). Exposure to air pollution and to smoke from nearby cigarette smokers (secondhand or passive smoke exposure) may cause flare-ups in people who have COPD but probably does not cause COPD. COPD tends to occur more often in some families, so there may be an inherited tendency in some people. A rare cause of COPD is a hereditary condition in which the body does not produce enough of the protein alpha-1 antitrypsin. The main role of this protein is to prevent neutrophil elastase (an enzyme in certain White Blood Cells ) from damaging the alveoli. Consequently, emphysema develops by early middle age in people with severe 