In a 2006 European study, the risk of developing lung cancer was:

• 0.2% for men who never smoked (0.4% for women)
• 5.5% for male former smokers (2.6% in women)
• 15.9% for current male smokers (9.5% for women)
• 24.4% for male “heavy smokers” defined as smoking more than 5 cigarettes per day (18.5% for women)

An earlier Canadian study quoted the lifetime risk for male smokers at 17.2% (11.6% in women) versus only 1.3% in male non-smokers (1.4% in female non-smokers).