Introduction , Summary , and Conclusions

Cigarette smoking is the largest preventable cause of death and disability in developed countries and is a rapidly growing health problem in developing countries. The magnitude and nature of the risks associated with smoking can be estimated using data from prospective epidemiological studies of smokers and nonsmokers and information on smoking in the population. In 1966 the National Cancer Institute (NCI) published the monograph Epidemiological Approaches to the Study of Cancer and Other Chronic Diseases (Haenszel, 1966), which included detailed presentations of the information available up to that time from several large prospective mortality studies examining relationships between smoking behavior and disease. Since then, several new large prospective mortality studies have been initiated, and additional years of followup are available for analysis for some of the studies whose results were presented in 1966. This new information can be used to more sharply characterize the risks of smoking.