RESUMO
Data are presented on cancer and total mortality among a representative sample of nonsmokers and the total population 35--84 years of age in the United States during 1966--68 that measured the influence of cigarette smoking on mortality rates, independent of other health-related factors. Of all U.S. white males, those who never smoked cigarettes have a total age-adjusted cancer death rate which is 37% less than that of males as a whole and 53% less than that of those who currently smoke cigarettes. Correspondingly, of all U.S. white females, those who never smoked cigarettes have a total age-adjusted cancer death rate which is 15% less than females as a whole and 33% less than that of those who currently smoke cigarettes. The largest cancer rate reduction in the nonsmokers is concentrated in the respiratory system. Nonsmokers have an age-adjusted total death rate which is about 20% less than the population as a whole and about 43% less than current cigarette smokers. These and other results and methodologic issues are discussed.