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SURGEON GENERAL'S REPORT ON THE HEALTH CONSEQUENCES OF SMOKING - 1967 Part I CURRENT I1IFORMATION ON THE HEALTH CONSEQUENCES OF SMOKING In January 1964, an Advisory Committee appointed by the Surgeon General of the Public Health Service issued its report (15) on the rela- tionship between smoking and health.* The conclusions of that Committee were summed up in the sentence: "Cigarette smoking is a health hazard of sufficient importance in the United States to warrant appropriate remedial action." In the three and one-half years since the publication of that report, an unprecedented amount of pertinent research has been completed, continued, or initiated in this country and abroad under the sponsorship of governments, universities, industry groups, and other entities. This research has been reviewed and no evidence has been revealed which brings into question the conclusions of the 1964 report. On the contrary, the research studies published since 1964 have strengthened those conclusions - . .. . .: : • .- . . . : _ .- • and have extended in some important respects our knowledge of the health ' ,-r! _.. ..)A . 7 ... . .. - . . . .... -_ . . _ .. . . . ., . ~ ... .-.. •_ ; ~'.. .t'i.i ~. - consequences of smoking. - *"Smoking and Health. Report of the Advisory Committee to the Surgeon General of the Public Health Service." It is frequently referred to in this manuscript as "the Surgeon General's 1964 Report." i . r ra.:FvT~+X • s•'l r

The present state of knowledge of these health consequences can, in the judgment of the Public Health Service, be summarized as follows: 1. Cigarette smokers have substantially higher rates of death and disability than their non-smoking counterparts in the population. This means that cigarette smokers tend to die at earlier ages and experi- ence more days of disability than comparable non-smokers. 2. A substantial portion of earlier deaths and excess disability would not have occurred if those affected had never smoked. 3. If it were not for cigarette smoking, practically none of the earlier deaths from lung cancer would have occurred; nor a substantial portion of the earlier deaths from chronic bronchopulmonary diseases (commonly diagnosed as chronic bronchitis or pulmonary emphysema or both); nor a portion of the earlier deaths of cardiovascular origin. Excess disability from chronic pulmonary and cardiovascular diseases would also be less. 4. Cessation or appreciable reduction of cigarette smoking could delay or avert a substantial portion of deaths which occur from lung cancer, a substantial portion of the earlier deaths and exc*ss disability from chronic bronchopulmonary diseases, and a portion of the earlier deaths and excess disability of cardiovascular origin. 2

4 0 NATURB OF RECffiPP RESEARCH FINDINGS Since the Surgeon General's ieport was published in January 1964, there has been a proliferation of additional studies and reports on smoking research. In the 12 years preceding that report, some 3,000 articles were published reporting research; since 1964, there have been more than 2,000 additional studies. These studies have helped to clarify the role that age plays in the relationship of smoking to health; the similarities and differences in the ways in which men and women are affected by smoking; and the influences and effects of stopping smoking, particularly in the case of lung cancer where there is significant data to show that sharp reductions in lung cancer deaths follow closely reductions in cigarette smoking. The studies also suggest the importance of a variety of measures of exposure; add substantial new information on the magnitude of the morbidity problem associated with smoking; and provide more adequate data upon which to base estimates of the magnitude of the mortality problem. Historically, concern about the effects of smoking began with observations of the extremely high frequency with which lung cancer patients were identif ied as cigarette smokers. These observations took on a fuller meaning with the first publication of the prospective studies in 1954 when higher overall death rates among cigarette smokers were identified. The rates were found to exceed the difference that could be Gb accounted for by lung cancer alone. Until that time, the possibility O ~ G7 remained that although more cigarette smokers appeared to suffer from ~ W Mr 3

4. lung cancer, if there were no s ignif icant excess overal l siortal ity, some other cause or causes of mortality would have had to be under-represented among cigarette smokers. The Surgeon General's 1964 Report concluded that cigarette smokers do have higher death rates than their non-smoking counterparts. This has 0 changed the emphasis of the present problem away from the question "does r cigarette smoking cause disease?" to the more precise questions of: 1. How much mortality and excess disability are associated with smoking? 2. How much of this early mortality and excess disability would not have occurred if people had not taken up cigarette smoking? 3. How much of this early mortality and excess disability could be averted by the cessation or reduction of cigarette smoking? 4. What are the biomechanisms whereby these effects take place and what are the critical factors in these mechanisms? To answer these questions one must not only study the details of the relationship of overall mortality with cigarette smoking, one must also turn to the specific causes of death and disability and to other kinds of evidence. The research carried on since 1964 is of three principal varieties: epidemiological studies, especially those which involve surveys of large 4

9 portions of the population; a health survey which has revealed new information about the relation between smoking and illness; and a vast amount of experimental, clinical, pathological and behavioral research which adds to the understanding of the precise ways in which smoking affects the body, plus other closely related or peripheral information. In the area of morbidity or illness, the primary addition to our knowledge is from "Cigarette Smoking and Health Characteristics," a report(16) of the National Center for Health Statistics on the frequency of illness among smokers and non-smokers in a large probability sample of the U. S. population. Regarding epidemiological data, new reports from four of the major population studies have been published since 1964: 1. The Dorn study of smoking and mortality among U. S. veterans. (13) 2. Hammond's study on smoking in relation to the death rates of one million men and women in 25 States. (11) 3. The DD11 and Hill study on the mortality of British physicians in relation to smoking. (8,9,10) 4. A Canadian Smoking and Health Study of Canadian pensioners, including veterans and dependents. (1) The principal features of the additional data provided by these four studies are: (1) the extension of the time period of follow-up, (2) the additional data available for specific age groups among men, and (3) the inclusion of substantial data on women. In all, the prospective study reports now available are based on more than 108,000 deaths, an increase of about 43,000 deaths over the 65,023 summarized in the 1964 Report. About 19,000 of these additional deaths were among women. 5

THE NATURE OF THIS REPORT - This report, which provides a susrmary of current information on the health consequences of smoking, is based on the review of the research reports which have become available since the study of the Surgeon General's Advisory Comittee was released. Public Health Service staff smbers consulted the literature and requested additional information or interpretations of the published data f roo the research scientists when needed. During this review a complete bibliography, containing some 5,700 citations, was compiled; it is now in manuscript form and will be published shortly.(19) The advice and coaoents of experts within the Public Health Service, particularly the Bureau of Disease Prevention and Esvironvental Control and the National Institutes of Health, as well as of specialists outside the Public Health Service, were solicited especially on matters involving judgment and evaluation. The general criteria used by the Surgeon General's Coe.ittee have been followed. First, epidemiological data were evaluated to determine whether an association exists. In judging the signif icance of the association, its consistency, strength, specificity, temporal relation- ship and coherence were utilized. The convergence of evidence from animal experiments, clinical and autopsy studies, and population studies remains the essential basis for evaluation of the signif icance of the associations identif ied. 41 6

This report presents, under the following headings, the major findings of research studies published in the past three to four years: 1. Smoking and Overall Mortality 2. Smoking and Overall Morbidity 3. Smoking and Cardiovascular Diseases 4. Smoking and Chronic Bronchopulmonary Diseases (Non-Neoplastic) 5. Smoking and Cancer t 6. Other Conditions and Research Areas Each of these sections is introduced by pertinent conclusions from the Surgeon General's 1964 Report, which are followed by discussion and conclusions of the present study. 7

SMOKING AND OVERALL MORTALITY - Conclusions of the Surgeon General's 1964 Report "Cigarette smoking is associated with a 70 percent increase in the age-specific death rates of males, and to a lesser extent with increased death rates of females. The total number of excess deaths causally related to cigarette smoking in the U. S. population cannot be accurately estimated. In view of the continuing and mounting evidence from many sources, it is the judgment of the Committee that cigarette smoking contributes substantially to mortality from certain specific diseases and to the overall death rate." "In general, the greater the number of cigarettes smoked daily, the higher the death rate. For men who smoke fewer than 10 cigarettes a day, according to the seven prospective studies, the death rate from all causes is about 40 percent higher than for non-smokers. For those who smoke from 10 to 19 cigarettes a day, it is about 70 percent higher than for non-smokers; for those who smoke 20 to 39 a day, 90 percent higher; and for those who smoke 40 or more, it is 120 percent higher. "Cigarette smokers who stopped smoking before enrolling in the seven studies have a death rate about 40 percent higher than non-smokers, as against 70 percent higher for current cigarette smokers. Men who began smoking before age 20 have a substantially higher death rate than those who began after age 25. Compared with non-smokers, the mortality risk of cigarette smokers, after adjustments for differences in age, increases with duration of smoking (number of years), and is higher in those who stopped after age 55 than for those who stopped at an earlier age. 8

t "In two studies which recorded the degree of inhalation, the mortality ratio for a given amount of smoking was greater for inhalers than for non-inhalers. "The ratio of death rates of smokers to that of non-smokers is highest at the earlier ages (40-50) represented in these studies, and declines with increasing age. "Possible relationships of death rates and other forms of tobacco use were also investigated... The death rates for men smoking less than 5 cigars a day are about the same as for non-smokers. For men smoking more than 5 cigars daily, death rates are slightly higher. There is some indication that these higher death rates occur primarily in men who have been smoking more than 30 years and who inhale the smoke to some degree. The death rates for pipe smokers are little if at all higher than for non-smokers, even for men who smoke 10 or more pipefuls a day and for men who have smoked pipes more than 30 years." CURRENT INFORNATION, 1967 .The primary addition to knowledge in the areas of smoking and overall mortality comes from the four major population studies. Additional periods of follow-up have provided a broader base from which it becomes possible to estimate the excess deaths related to cigarette smoking in the U. S. population and from which firmer conclusions may be drawn as to the role of various exposure factors in the associations found. The contributions since 1964 of each of the four population studies to the relation of smoking and overall mortalitg, as sumanarized by the authors, are set forth below. 9

Study of U. S. Veterans: (An eight and one-half year follow-up of 293,658 persons holding U.S. Government Life Insurance Policies. Commonly referred to as the Dorn Study after the late Dr. Harold F. Dorn. The most recent report is by Kahn (13).) n ...the increased mortality risk associated with cigarette smoking was found to be higher in the more recent calendar time period than in the initial years of the study. "...mortality ratios of current cigarette smokers compare with those who have never smoked are 1.7 for death from all causes, 10.9 for lung cancer, 12.2 for emphysema without bronchitis, and 1.6 for coronary heart disease. Paralysis agitans was the only cause of death associated with significantly lower mortality for smokers than for non-smokers. "For all categories of current smokers, risk was related to amount smoked. The risk for cigarette smokers was much greater than that for pipe or cigar smokers. Current smokers of cigarettes, cigars, or pipes experienced a mortality risk significantly greater than that for non-smokers if they smoked more than four pipes or four cigars daily or more than an occasional cigarette. "There was a positive relationship between duration of cigarette smoking and mortality risk from all causes of death for at least some classifications of smokers." ":..probabilities of death for ex-smokers of cigarettes revealed a downward trend in risk as duration of time discontinued increased, when other variables -- age began smoking, amount smoked, and current age -- .GD 10