Smoking
About 90% of lung cancers arising as a result of tobacco use, 25 times higher than a nonsmoker. Pipe and cigar smoking also can cause lung cancer, although the risk is not as high as with cigarette smoking.
Passive smoking
24% increase in risk for developing lung cancer
Asbestos fibers
Asbestos workers who do not smoke have a fivefold greater risk of developing lung cancer than nonsmokers, but asbestos workers who smoke have a risk that is fifty- to ninetyfold greater than nonsmokers.
Radon gas
An estimated 12% of lung-cancer deaths attributable to radon gas, or about 20,000 lung-cancer-related deaths annually in the U.S., one out of every 15 homes in the U.S. contains dangerous levels of radon gas. Radon gas is invisible and odorless, but it can be detected with simple test kits.
Familial predisposition
Lung diseases
The presence of certain diseases of the lung, notably chronic obstructive pulmonary disease (COPD), is associated with an increased risk (four- to sixfold the risk of a nonsmoker) for the development of lung cancer even after the effects of concomitant cigarette smoking are excluded.
Prior history of lung cancer
Air pollution
