Smoking is the most preventable cause of death in the United States.
Cigarette smoking is by far the most important risk factor in the development of lung cancer. One in five deaths in the United States results from the use of tobacco. Ninety percent of new smokers are children and teenagers. Nonsmokers exposed to smoke are also at an increased risk for lung cancer. The rate of lung cancer among men as a whole in the U.S. has been declining in recent years.