Smoking Is a Major Cause of Emphysema
In the vast majority of people, smoking is the cause of emphysema. Exactly how smoking destroys the air sac linings in the lungs isn't known. However, population studies show that smokers are about six times more likely to develop emphysema than nonsmokers.
Estimates vary, but more than 24 million people in the U.S. likely have emphysema or another form of COPD, and probably many of them don't know it. Emphysema and chronic bronchitis are the third-leading cause of death in the U.S.
Interestingly, most heavy smokers do not develop emphysema. Why some smokers get emphysema and others do not is unknown. All heavy smokers experience other negative health effects of smoking, though