During the study, 2333 women and 4680 men died between the ages of 40 and 70 years. Death rates were much higher among those who smoked 20 or more cigarettes per day than among people who never smoked. During the study, 26% of women who were heavy smokers died compared with only 9% of women who were nonsmokers. Among men, 41% of heavy smokers and only 14% of nonsmokers died. At each age and at each level of smoking, male smokers had higher death rates than female smokers. Lung cancer deaths were the same in men and women smokers, but male smokers had a higher risk for cardiovascular death than women with similar smoking behaviors. The lower baseline risk for cardiovascular disease in women than in men at similar ages explains these differences. Not surprisingly, the younger smokers were when they quit, the more they lowered their risk for death. However, even among the oldest participants, quitting smoking had a benefit.