Table 2.

Established and putative risk lung cancer risk factors

Risk factorMagnitude of association
Tobacco smoking20-fold increased risk vs. never smoker
Secondhand smoke25% to 28% increased risk vs. never smoker
Electronic cigarettesPresently unknown
Other tobacco use (cigars, pipes, water pipes)1.9- to 4.6-fold increased risk
Smoked cannabisPresently no known risk
Radon14% to 29% increased risk
Asbestos12% to 24% increased risk
History of COPD, emphysema, or chronic bronchitis2- to 3-fold increased risk
History of asthma28% to 44% increased risk
History of pneumonia30% to 57% increased risk
History of Chlamydia pneumoniae1.2- to 2.4-fold increased risk
History of tuberculosis48% to 76% increased risk
HIV2-fold increased risk

Abbreviation: COPD, chronic obstructive pulmonary disease.