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The Benefits of Cessation of Smoking
The Benefits of Cessation of Smoking Leonard M. Schuman, M.D."
he overwhelming epidemiologic, clinical and labToratory evidences for the relationship of cigarette smoking to disease have been so extensively documented and evaluated'-hnd so widely disseminated through the world scientific literature and the press that it would be superfluous to review them extensively at this time. However, a brief display of selected basic observations will assist in orienting our approaches to the problems of the smoking patient. The magnitude of the problem, demonstrable in many countries of the world and demanding increased attention from practitioners of medicine and serious response from the population, is exemplified by data from the United States. The diseases associated with tobacco use are presented in Table 1. These diseases contributed 48 percent of the total U.S. mortality in 1967. If we restrict ourselves solely to those diseases for which a causal relationship with tobacco use is deemed to be firm or highly probable, they contributed 37 percent to total mortality. These, however, are inclusive data: they do not separate the smoking segment of the population nor the contribution which smoking makes to disease-specific mortality. We need an indicator of public health significance-a measure of the number of people affected by the factor and hence a measure of the magnitude of the problem for the total population. Such an indicator is the excess deaths among smokers over those among nonsmokers as a percentage of total deaths in the group. This measure takes into account not only the differences in death rates between smokers and nonsmokers but also the proportion of smokers in the population under study. This is important to the consideration of public health significance for it is obvious that even with a large death rate differential between smokers and non-smokers a population with very few smokers would have very few excess deaths. Utilizing the data from the prospective studies on
smoking among veterans by Dorn and the %-state study by Hammond, Horn determined that, for men between the ages of 35 and 60, approximately onethird of all their deaths would not have occurred if cigarette smokers had the same death rates as nonsmokers.:' The potential for prevention is immediately obvious. To the smokers among the very young such data frequently leave them unresponsive for in their minds the mortality producing diseases related to smoking are diseases of the extreme end of life-so far in the future as to pose no threat at all or, at worst, a small price to pay for the pleasures of today. To the inveterate smokers among the population groups in the prime years of life's productivity-ages 45-49--such data may well evoke the response: ". . . but we all have to die sometime and from something." To such smokers the physicians' armamentarium need not be without response, for he has at his command quite solid epidemiologic evidence that mortality related to smoking is premature mortality. The evidence is available in two
'Professor and Head, Division of Epidemiology, School of Public Health, University of Minnesota, Minneapolis, hlinn.
Source: Vital Statistirs of the {J.S., 1867, vol. 11, Mortality, Part A.6
Table 1-Mortality front Selected Chronic Diseases Related t o Tobacco Smoking, United States, 1967 Sumbcr deaths
Diseases
Causally related: 54,407 Canrer of lung, bronrhus, trachea (162,163) Chronic 1)ronrhitis and emphysema (501,502,527.1) 26,181 Cancer of larynx (161) 2,707 143 Cancer of lip ( 140) Prohably causally related: Coronary heart disease (420) 573,153 8,563 Cancer of bladder ( 1 81.0) Cancer of buccal cavity and pharynx (141-148) 6,575 Cancer of esophagus (150) 5,627 Possil)ly causally related: Cerebrovascular disease (330-334) 202,184 Aortic aneurysm (451) 11,621 801,251
Total Total mortality, all causes
1,851,323
-
LEONARD M. SCHUMAN Table 2-Loss
in Life Expectancy ( i n years and as a percentage of total life expectancy of non-smokers) at Various Ages for Cigarette Smokers Hammond Study US., 19677
Numlwr of Cigarettes Smoked per Day 1-!)
Age
Ye:w I~0kt
25 years 30 years 35 years 40 years 45 years 50 yc,ars 55 years 6(! years 6.5 years
4.6 4.6 4.5 4.3 4.1 3.8 3.5 3.1 2.8
10-19
%
Yc-ar Lost
9.5 10.5 11.5 12.5 13.7 14.8 16.4 17.6 19.9
5.5 5.5 5.4 5.2 5.0 4.6 4.0 3.5 2.9
forms: loss in life expectancy and excess mortality in the several pertinent age groups. Hammond, from the data on the U.S. men in his 25-state study, utilizing the life expectancy of the men who never smoked regularly as the standard, was able to calculate the loss in life expectancy at various ages among the regular cigarette smokers. Table 2 presents these data.7 In any single age group the percentage of life expectancy lost among smokers increases with the amount of cigarettes smoked per day; and at any level of smoking the percentage of life expectancy lost increases with age. However, from these data it can readily be seen that the greater absolute number of years lost in life expectancy occurs among the younger age groups for any level of smoking. Both the Dornh study of veterans and the Hammond!' study of over 1,000,000 men and women in 25 states provided data for Horn's calculations of excess deaths among smokers as percentages of total mortality in the relevant age and sex groupse3 Excess deaths among smokers were the number of deaths over and above those which would have occurred if smokers had the same death rates as those who never smoked regularly. Although there is an excess mortality among cigarette smokers in each age group, Horn's calculations reveal these smoking-related excesses to be proportionately higher for the younger age groups. In both studies the male excess smoker mortality was proportionately greatest in the 45-54 year age group. This excess was 43 and 38 percent respectively of the total mortality in this age group. The second highest proportionate excess was in the 35-44 year age group (33 percent in both studies.) In the age groups beyond 54 years the proportionate excesses declined progressively. Women smokers in the Hammond study also experienced their highest proportionate excess mor-
40 and over
20-39
Years Lost
%
Years Lost
%
tality in the 45-54 year age group. This excess was of a lower magnitude than for the men, but was still a significant 9 percent of their total age-specific mortality. Thus, the impact of smoking-related mortality is felt predominantly in the prime years of life for both men and women. This is evidence enough to appeal to man's evocable, albeit subconscious, striving for a measure of immortality. We must, in turn, not overlook a possibly more immediate patient concern and that is illness which disables for longer or shorter periods, which reduces his productivity and restricts even his more or less spiritual activities-in short, which reduces the quality of life for him and his family. Information on excess morbidity related to smoking has become available through periodic inquiries on smoking among those in the probability samples of the ongoing National Health Survey.1" In this survey, disabling illness has been measured in three ways: days lost from work, days in which activity has been restricted, and days confined to bed. For all three types of disability and for both men and women, higher morbidity ratios, greater morbidity rates and higher percentages of excess disability days are found among cigarette smokers." As with mortality, excess disability days among smokers of cigarettes is greater, proportionately, in the relatively younger age groups. Among men smokers, the 45-64 year age group reported the highest excess morbidity-a 28 percent excess of disabling illness by each of the three morbidity measures. The 17-44 year age group was next with a 20-23 percent excess. Among women smokers, disabling illness occurred in highest excess in an even younger age group-those 17-44 years of age-with the age group 45-64 showing the next highest morbidity excess. The National Health Survey also provides data on prevalence of chronic conditions among smokers and non-smokers. It is of further interest not only CHEST, VOL. 59, NO. 4, APRIL 1971
BENEFITS OF CESSATION OF SMOKING that the smokers have higher prevalence rates of chronic conditions, but that the excess prevalence of such chronic conditions among young smokers ( 1744 years of age) is proportionately higher than for all older age groups.1" This is true for both men and women. For both the three measures of disability and the prevalence rates of chronic conditions a dose-eflect gradient with amount of cigarettes smoked per day was demonstrated. It is thus quite apparent that smoking is also strongly related to prematurely disabling illness. Despite these evidences of the gravity and magnitude of the problem the physician will frequently share the pessimism of the long-time smoker, the heavy smoker who questions the value of cessation of smoking-who himself states "I've been smoking so long, the damage has been done. \Vhat can be gained by stopping?" Data from the prospective studies would tend to refute this pessimism for these reveal repeated evidences of advantageously lower risks of mortality among smokers who have discontinued the habit than among continuing smokers. In the first portion of Table 3, general mortality among smokers and ex-smokers of cigarettes is expressed as a ratio relative to mortality in non-smokers. For each of the five studies in which the classes of smokers could be separated, excigarette smokers had distinctly lower risks than continuing smokers. Of importance to the skeptical patients who believe that their situation is hopeless for having smoked excessively for a great number of years is the reduction in mortality risk noted in several studies after cessation of smoking."ven if the patient has smoked more than a pack a day for 2.535 years, his risk of death is materially reduced. Even if he has smoked more than a pack a day, very significant gains are apparent if he quits at ages 4554. If he smokes no more than a pack a day then, even at ages over 55, significant reduction in risk is evident. If he remains a discontinued smoker for five to ten years, his risk of death is reduced almost to that of one who has never smoked.'' Gains in reduction of disease-specific mortality by cessation are even more dramatic for several of the specific entities associated with cigarette smoking. Even with the relatively short term followup data available during the evaluation of the prospective studies for the Advisory Committee's Report to the Surgeon Genera1,Z significant reductions in risk on cessation of smoking had been noted for all but one of the several diseases associated with cigarette smoking. Chronic bronchitis and emphysema mortality was actually higher among ex-smokers than current cigarette smokers. (This was a phenomenon
CHEST, VOL. 59, NO. 4, APRIL 1971
also noted in the total mortality rates for discontinued pipe and cigar smokers at that time.) Since the data on ex-cigarette smokers were generally not adjusted for duration of discontinuance or for reasons for discontinuance ( e g doctor's orders or severity of already-existing illness) this apparent discrepancy in an opposite direction was probably an artifact. Actually, it can be shown by more recent data derived from longer term follow~ ~ reduction in risk up in at least two s t u d i e s s ~that of mortality from chronic bronchitis and emphysema does indeed occur with cessation of smoking cigarettes. Table 3 presents these recent data by specific prospective study and for specific disease entities. A remarkable consistency in the reduction of mortalTable 3--Comparison of Mortality Ratios of Ex-Cigarette S n ~ o k e r swith Current Cigarette Smokers
Entity Total hlortnlity (2): British physicians (Doll and Hill) hlen in 9 States (Hammond and Horn) U.S. veterans (Dorn) Canadian veterans (Best et al) Men in 25 states (Hammond) Cause-Specific hlortality: Lung Cancer U.S. veterans (Dorn) (8) 25 states (Hammond) (9) Canadian veterans (Best et al) (13) British physicians (Doll and Hill) (14) Chronic Bronchitiv and Emphysema U.S. veterans (8) British physicians (14) Cancer of Laryw (2) Cancer of Oral Catrily U.S. veterans (8) Cancer of Eeophapua U.S. veterans (8) Cancer oj Bladder U.S. veterans (8) Coronary Heart Disease U.S. veterans (8) 25 states (11) British physicians (14) Cerebrovascular Disease U.S. veterans (8) 25 states (11)
Aortic Aneurysm (non-syphilitic) U.S. veterans (8) Cirrhosis of the Liver U.S. veterans (8)
1-19ciga/day 20+
1.44 1.70 1.79 1.65 1.83
1.04 1.40 1.41 1.42 1.50
12.1 6.5 13.7
5.0 2.0 7.9
(& ::::) 17.3 17.4
a
i
d
a
6.1
3.4
10.1 11.6 7.1
7.6 7.6 5.4
4.1
2.1
6.2
1.6
2.2
1.6
1.7 1.9 2.6 1.4
1.3 1.2 1.3 1.1
1.5 1.5 1.9
1.2 1.0 0.9
5.2
3.0
3.3
1.1
LEONARD M. SCHUMAN
ity ratios among ex-cigarette smokers for each specific disease is apparent among the several studies. The extension of the studies over a longer period of followup minimized the impact of the earlier higher mortality among those who discontinued smoking because of severe illness. In the U.S. veterans study, with the largest number of accumulated deaths (over 46,000) of any of the prospective studies, the volume of the data and the foresight of the investigator permitted the development of a subcategory of discontinued smokers who stopped smoking for reasons other than "doctor's orders." The data on ex-smokers of cigarettes derived from the U.S. veterans study are for this category of discontinued smokers.8 In the most recent analyses of the Hammond 25state data, the investigators confined themselves to the study of the approximately 80 percent of their subjects who, at the time of enrollment, had no history of heart disease or stroke, no history of cancer diagnosed within the preceding five years and were not sick.11 In this manner smokers who had discontinued smoking because of ill health prior to the time of enrollment were excluded. It is noteworthy that the greatest reductions in risk are to be found for the cancers associated with cigarette smoking. This is not surprising when it has been noted that the greater the magnitude of the relative risk the more likely that cigarette smoking is the principal causal factor in the disease. Lower relative risks imply other related factors may also be causally operating. Because of the relatively small mortality ratios observed for coronary heart disease, the magnitude of the gains from cessation of smoking cigarettes may be inapparent on superficial inspection. Cornfield and Mitchell12 hold a conservative attitude with regard to the degree of decrease in risk with smoking discontinuance. They cite the persistence of some coronary mortality effect after at least a decade of discontinuance of smoking, but do acknowledge significant reductions in risk. Because of the magnitude of the coronary heart disease
problem, what appears as a small reduction in ratio is a highly significant reduction in absolute death rates from this cause. Table 4 demonstrates this point. The differences between the rates for current smokers and for ex-smokers represent the gains for the specific levels of smoke exposure and for the several age groups. As an illustration, in the 55-64 year age group, discontinued smokers who had smoked more than two packs of cigarettes per day achieved a coronary heart disease mortality risk level which was 455 deaths per 100,000 less than those who continued to smoke at that dose-rate. This latter smoking group experienced a coronary heart disease mortality rate of 1101 per 100,000. Thus, a 41 percent reduction in mortality risk is. certainly meaningful. This can also be seen in the 25-state study of Hammond with respect to the length of time smoking of cigarettes had been discontinued and the level of smoking which had prevailed prior to such discontinuance. In Table 5 it can be seen that, for both levels of smoking, the longer the discontinuance, the greater the reduction in risk, and after ten years the risk is, respectively, equal to or almost equal to that of those who never smoked. Since there continue to be those who would refute these data with the charge of selective bias, nature has obligingly produced a situation similar to a controlled cessation experiment. In England and Wales, a considerably large reduction in cigarette smoking among physicians followed upon the first Doll and Hill report in 1954, whereas among the general population, cessation of smoking was not a common phenomenon. In the general population, increases in mortality from lung cancer and cardiovascular diseases have taken place in the 10- to 11year period following this report. Whereas the lung cancer mortality in the general male population, aged 35-84, increased from 1.49 to 1.86 per 1000 population per year between the periods 1954-57 and 1962-64, an increase of 25 percent, the lung cancer mortality among the same-aged British physicians actually declined from 1.09 to 0.76 per 1000
Table 4--Annual Death Rate per 100,000 from Coronary Heart Disease b y Age, Cigarette-Smoking Status and Number of Cigmettes Smoked per Day, U.S. Veterans Study ( 8 )
Number smoked per day1 1 to 9
10 to 20 21 to 39 40
+
Current cigarette smokers 195 297 390 502
45-54
Exsmokers2
Current cigarette smokers
125 133 57 -
594 830 912 1,101
55-64
Exsmokers2
Current cigarette smokers
432 557 743 646
1,374 1,577 1,701 1,955
65-74
Exsmokers2 1,105 1,200 1,366 1,482
IThis is the current rate of smoking for current cigarette smokers and the maximum rate attained for ex-cigarette smokers. 2Ex-smokers who stopped for reasons other than doctor's orders.
CHEST, VOL. 59, NO. 4, APRIL 1971
BENEFITS OF CESSATION OF SMOKING Table
5--Coronary Heart Disease ( M e n ) . Age-Standardized Death Rates for Ex-Cigarette Smokers with History of Cigarette Smoking Only, by Former Number Smoked per Day and Years Since Last Cigarette Smoking. Death Rates for Current Cigarette Smokers with History of Cigarette Smoking Only and M e n W h o Never Smoked Regularly are Shown for Concparison. M e n Aged 50-69'"
Smoked 1-19 cigarettes a day Ex-rigarette smokers (years since last cbigarrtte smoking)
Xumber men
Number deaths
8,569 22,808 55,728
210 78 1 1,114
Smoked 20
Death rate
+ cigarettes a day
Sumber men
Number deaths
21,624 56,886 55,728
630 1,895 1,114
Death rate
Undcr 1 year 1 to 4 years 5 to 9 years 10+ years Total ex-smokers Current cigarette smokers Never smoked regularly
635 947 502
813 1,029 502
'Four or more but less than 10 deaths expected in some of the component 5 y e a r age groups.
population in the same period; a reduction of 30 p e r ~ e n t . 1Similarly, ~ whereas the total cardiovascular disease mortality among the general male population aged 35-64 increased 10 percent between the periods 1953-57 and 1961-65, mortality from these diseases actually declined by 6 percent among the British physicians.'" May I once more turn your attention from mortality to illness studies, for it is in this area of maintenance of health and alleviation of symptoms of disease that a more successful appeal to the smoker may probably be made. A large number of prospective studies in the United States and abroad have directed their attention to coronary heart disease incidence and morbidity. Notable among these in the United States are the studies at Framingham, Massachusetts and Albany, New York; the Peoples Gas and Light Co. and Western Electric Co. studies in Chicago, Illinois; the fivecounty study in North Dakota; the Western Collaborative Study; the Health Insurance Plan Study in New York City; the Los Angeles Heart Study; and the Tecumseh, Michigan, Study. The prospective and retrospective studies of Dorken, Friedmann, and Schimmler, respectively, in Germany, Mulcahy in Ireland, Medalie in Israel, Hyams in Japan, Natvig in Norway and Heyden-Stucki in Switzerland are also of significant note. From among these studies several have gathered sufficient data permitting analyses of incidence rates for current and discontinued smokers. Table 6 reveals the decline in risk with discontinuance of cigarette smoking in three prospective studies. In the Western Collaborative Group Study this decline was significant for the 50-59 year age group only. In the younger age group the risk among discontinued smokers was approximately the same as for the continuing moderate to heavy smokers. However, since no information is available on reasons for discontinuance nor length of time of such disconCHEST, VOL. 59, NO. 4, APRIL 1971
tinuance, the meaning of this lack of difference in the younger age group cannot be determined. Morbidity from bronchopulmonay entities is probably most evident to the smoker even if he is suffering from relatively mild pathology such as a chronic productive cough. Furthermore, it is with this group of disease entities that remarkable diminution or disappearance of symptoms follow rapidly after cessation of smoking. We are indebted to the National Health Survey for data on the prevalence of chronic bronchitis and/or emphysema among smokers of cigarettes, non-smokers and ex-smokers.10 Among young men aged 17 years and over, ex-smokers revealed an ageadjusted prevalence rate of 2.5 cases per 100 as compared with 3.3 cases for current smokers of Table M o m p a r i s o n
of Risks of Developing Coronary Heart Disease Among Continuing and Ex-Smokers of Cigarettes
Study (Reference)
Relative Risk (non-smoker = 100) Current ExCigarette Cigarette Smokers Smokers
Framingham and Albany!'' <20 cigs/day 20 cigs/day >20 cigs/day
179 185 274
North Dakota Is*
22 1
107
Western Collaborative Group 19** a ) 39-49 year age group: 1-15 cigs/day 16-25 26
142 247 272
1 } 258 i
124 188 228
} 1
+
b)
50-59 year age group: 1-15 cigs/day 16-25 26
+
!
I
) 107
1
104
*Myocardial infarction only. **All coronary heart disease. Calculated from authors' data.
LEONARD M. SCHUMAN more than a pack per day. Among women, the ageadjusted prevalence for ex-smokers was 2.6 cases per 100 as compared with rates of 4.0 per 100 for smokers of one-half to one pack a day and 6.5 per 100 for smokers of more than a pack a day-an even more favorable reduction in risk. These data of the National Health Survey are of special interest, since it is entirely likely that the real effects of cessation of smoking may in part be masked by the possibly greater tendency for discontinuance among those disabled by severe bronchopulmonary disease. When one turns to symptoms and pulmonary function tests rather than finite diagnoses with their difficulties of definition, the benefits of cessation are more readily discernible. A number of surveys have demonstrated much lower proportions of individuals with chronic cough and with phlegm among exsmokers than among those continuing cigarette smoking-proportions which approach the prevalence in non-smokers. One such study of a total regional population in Finland by Huhti20 provides the data for Table 7 which is illustrative of many. Markedly lower prevalences of cough and phlegm among men ex-smokers are noted even in comparison with the continuing smokers of small numbers of cigarettes per day. Similar contrasts are noted for women ex-smokers, but the continuing smokers of 15 or more cigarettes per day among women were too few for a statement of significance. Coates et al,*l in their study of Detroit postal workers, found the ex-smokers to have prevalences of chronic cough and phlegm equal to that of nonsmokers. Holland,22 in a study of van-drivers in London and rural towns in England and in East Coast towns of the United States, found the proportions with chronic cough and phlegm among exsmokers of cigarettes much closer to that in nonsmokers than among even the continuing light smokers (from 1-14 cigarettes per day) of cigarettes. Table 7-Percent of Men and Women with Cough ( 3 months in the year) and with Phlegm ( 3 months in the year) Related to Smoking Habits ( 2 0 ) Cigarettes smoked per day Cough : Men Women
25+
N ~ ~ E- ~ smokers smokers
1-14
15-24
31.5 10.4
40.8 42.4 (3 of 7 women smoking 15+
4.1 4.5
8.5 13.3
42.9 42.4 (4 of 7 women smoking 15+
10.7 5.9
17.7 13.3
rigarettes/day
Phlegm : Men Women
38.0 10.4
cigaret tes/dav
In some of these prevalence studies pulmonary function tests accompanied the medical questionnaires. Here also the ex-smoker of cigarettes showed values for 1-second forced expiratory volume and peak expiratory flow rates significantly higher than those for continuing smokers and almost as high as the values for non-smokers.*0.2:{ Evidences from these cross-sectional studies suggest the inference that cessation of cigarette smoking in the individual brings improvement in pulmonary function and diminution or eradication of chronic respiratory symptoms. Support for such an inference is found in longitudinal studies which reexamined the same subjects at a reasonable interval of time. The studies by Higgins and associates,"" Holland and Elliott,*-' and Fletcher" are examples of note. More recently Comstock and his co-workers,20 in a study of men telephone company employees re-examined after a five-year interval, found marked improvement in the prevalence of cough and phlegm among those who had quit smoking cigarettes between the two surveys. Furthermore, though FEV1 values for all smoking classes declined between examination rounds, the ex-smokers of cigarettes showed the smallest decline and thus more closely approached the value for the nonsmokers. Experimental evidence also supports these findings. The studies of Krumholz et al," with smoking subjects who abstained for six weeks, revealed significant increases in peak flow rates, diffusing capacity, inspiratory reserve volume and maximal voluntary ventilation. Heart rate, oxygen debt after exercise and functional residual capacity was decreased. Wilhelmsen" demonstrated marked decreases in coughing, sputum production and wheezing in a group of long term smokers who abstained from cigarette smoking for 40 days. A significant increase in FEVl.o also occurred. Peterson and coworkers*!) similarly demonstrated significant increases in pulmonary function and decreases in coughing and breathlessness among smokers of cigarettes after 18 months of abstinence. Finally, autopsy materials on discontinued smokers reviewed by Auerbach et a13" reveal changes in the tracheobronchial tree (such as loss of cilia, basal cell h~perplasiaand atypical cells) in quantitative proportions more nearly like that of non-smokers as opposed to moderate or heavy smoker patterns. Similarly, these same investigators found a lesser degree of pulmonary fibrosis, rupture of alveolar septa and thickening of the walls of small arteries and arterioles in the pulmonary parenchyma of individuals who had stopped smoking cigarettes for five years or more than among current smokers.:!'
,,
CHEST, VOL. 59, NO. 4, APRIL 1971
BENEFITS OF CESSATION OF SMOKING Thus, there is good evidence of reversal of bronchitic changes and some intimation of reversal of parenchymal change or at least arrest. In summary, it can be said with great optimism that cessation of smoking does indeed reverse a number of processes and arrest others, short of morbidity or, at worst, premature mortality. To the benefits in terms of reduction of disease and disability must be added the increase in comfort, the feeling of well-being and positive health, not to mention the esthetic gains of a fresh smelling breath and a clear atmosphere. This optimism can and must be carried into office practice and communicated as prognosis to the scoffing young smoker and the inveterate older chronic smoker.
1 Royal College of Physicians of London: Smoking and Health. Summary and Report on Smoking in Relation to Cancer of the Lung and other Diseases. London, Pitman, 1962 2 U. S. Public Health Service: Report of the Advisory Committee on Smoking and Health to the Surgeon General. PHs Publication No. 1103, U. S. Government Printing Office, Washington, D.C., 1964 3 U. S. Public Health Service: The Health Consequences of Smoking. A Public Health Service Review: 1967. PHs Publication No. 1696, U. S. Government Printing Office, Washington, D.C., 1967 4 U. S. Public Health Service: The Health Consequences of Smoking: 1968 Supplement to the 1967 Public Health Service Review. PHs Publication No. 1696-1, U. S. Government Printing Office, Washington, D.C., 1968 5 U. S. Public Health Service: The Health Consequences of Smoking: 1969 Supplement to the 1967 Public Health Service Review. PHs Publication No. 1696-2, U. S. Government Printing Office, Washington, D. C., 1969 6 U. S. National Center for Health Statistics: Vital Statistics of the United States, 1967. Yiortality, Vol. 11, Part A, U. S. Government Printing Office, Washington, D.C., 1969 7 Hammontl EC: Life expectancy of American men in relation to their smoking habits. In Summary of the Proceetlings of World Conference on Smoking and Health, National Interagency Council on Smoking and Health, New York City, September 11-13, 1967 8 Kahn HA: The Dorn sh~clyof smoking and mortality among U. S, veterans: report on 8%years of observation. In: Haenszel W, editor. Epidemiological Approaches to the Study of Cancer and other Diseases. Bethesda, U. S. Puhlic Health Service, National Cancer Institute Monograph No. 19, January 1966 9 Hammond EC: Smoking in relation to the death rates of one million men and women. In: Haenszel W, editor. Epidemiological Approaches to the Study of Cancer and other Diseases. Rethesda, U. S. Public Health Service, National Cancer Institute Slonograph No. 19, January 1966 10 U. S. Public Health Service: National Center for Health Statistics. Cigarette smoking and health characteristics, United States, Jt~ly1964 to June 1965. Vital and Health Statistics series 10, No. 34, U. S. Public Health Service Publication No. 1000, Washington, D. C., Xlay 1967
CHEST, VOL. 59, NO. 4, APRIL 1971
11 Hammond EC, Garfinkel L: Coronary heart disease, stroke, and aortic aneurysm. Arch Environ Health 19: 167182, 1969 12 Cornfield J, Mitchell S: Selected risk factors in coronary disease. Possible intervention effects. Arch Environ Health 19:382-394, 1969 13 Best EWR: A Canadian study of smoking and health. Department of National Health and Welfare, Ottawa, 1966 14 Doll R, Hill AB: llortality in relation to smoking: 10 years observation of British doctors. Brit hled J 1 (5395) : 1399-1410 and 1 ( 5396) : 1460-1467, 1964 15 Doll R: Cancer bronchique et tabac. Bronches (Paris) 16:313-324, 1966 16 Fletcher CM, Horn D : Smoking and health. WHO Chronicle 24:345-370, 1970 17 Doyle JT, Dawber TR, Kannel WB, et al: The relationship of cigarette smoking to coronary heart disease. JAhlA 190:886-890, 1964 18 Zukel WJ, Lewis RH, Enterline PE, et al: A short-term community study of the epidemiology of coronary heart disease. Amer J P H 49:1630-1639, 1959 19 Jenkins CD, Rosenman RH, Zyzanski SJ: Cigarette smoking. Its relationship to coronary heart disease and related risk factors in the Western Collaborative Group Study. Circulation 38: 1140-1155, 1968 20 Huhti E: Prevalence of respiratory symptoms, chronic bronchitis and pulmonary emphysema in a Finnish rural population. Acta Tuherculosea et Pneumologica Scandinavica ( Kobenhavn) Supplementum 61, 1965 21 Coates EO Jr, Bower GC, Reinstein N: Chronic respiratory disease in postal employees. JAhlA 191 : 161-166, 1965 22 Holland WW, The natural history of chronic bronchitis. J College of General Practitioners 11: Supp. 2:8-16, 1966 23 Higgins ITT, Gilson JC, Ferris BG, et al: Chronic respiratory diseases in an industrial town: A nine year follow-up study. Amer J Public Health 58: 1667-1676, 1968 24 Holland WW, Elliott A: Cigarette smoking, respiratory symptoms and anti-smoking propaganda. An experiment. Lancet 1:41-43, 1968 25 Fletcher ChZ: Bronchial infection and reactivity in chronic bronchitis. J Roy Coll Phys Lond 2: 183-190, 1968 26 Comstock GW, Brownlow WJ, Stone RW, et al: Cigarette smoking and changes in respiratory findings. Arch Environ Health 21:50-57, 1970 27 Kmmholz RA, Chevalier RB, Ross JC: Changes in cardiopuln~onaryfunctions related to abstinence from smoking. Ann Int Med 62: 197-207, 1965 28 Wilhelmsen L: Effects on bronchopulmonary symptoms, ventilation and lung mechanics of abstinence from tobacco smoking. Scandinavian J Resp Dis 48:407-414, 1967 29 Peterson DI, Lonergan LH, Hardinge hlG: Smoking and pulmonary function. Arch Env Health 16:215-218, 1968 30 Auerbach 0 , Stout AP, Hammond EC, et al: Changes in bronchial epithelium in relation to sex, age, residence, smoking and pneumonia. New Eng J l l e d 267: 111-119, 1962 31 Ar~erbach0 , Stout AP, Hammond EC, et al: Smoking habits and age in relation to pulmonary changes. Rupture of alveolar septums, fibrosis and thickening of walls of small arteries and arterioles. New Eng J Med 269: 10451054, 1963 Reprint requests: Dr. Schuman, 1158 Mayo hle~norialBuilding, University of Minnesota, Minneapolis 55455.
he overwhelming epidemiologic, clinical and labToratory evidences for the relationship of cigarette smoking to disease have been so extensively documented and evaluated'-hnd so widely disseminated through the world scientific literature and the press that it would be superfluous to review them extensively at this time. However, a brief display of selected basic observations will assist in orienting our approaches to the problems of the smoking patient. The magnitude of the problem, demonstrable in many countries of the world and demanding increased attention from practitioners of medicine and serious response from the population, is exemplified by data from the United States. The diseases associated with tobacco use are presented in Table 1. These diseases contributed 48 percent of the total U.S. mortality in 1967. If we restrict ourselves solely to those diseases for which a causal relationship with tobacco use is deemed to be firm or highly probable, they contributed 37 percent to total mortality. These, however, are inclusive data: they do not separate the smoking segment of the population nor the contribution which smoking makes to disease-specific mortality. We need an indicator of public health significance-a measure of the number of people affected by the factor and hence a measure of the magnitude of the problem for the total population. Such an indicator is the excess deaths among smokers over those among nonsmokers as a percentage of total deaths in the group. This measure takes into account not only the differences in death rates between smokers and nonsmokers but also the proportion of smokers in the population under study. This is important to the consideration of public health significance for it is obvious that even with a large death rate differential between smokers and non-smokers a population with very few smokers would have very few excess deaths. Utilizing the data from the prospective studies on
smoking among veterans by Dorn and the %-state study by Hammond, Horn determined that, for men between the ages of 35 and 60, approximately onethird of all their deaths would not have occurred if cigarette smokers had the same death rates as nonsmokers.:' The potential for prevention is immediately obvious. To the smokers among the very young such data frequently leave them unresponsive for in their minds the mortality producing diseases related to smoking are diseases of the extreme end of life-so far in the future as to pose no threat at all or, at worst, a small price to pay for the pleasures of today. To the inveterate smokers among the population groups in the prime years of life's productivity-ages 45-49--such data may well evoke the response: ". . . but we all have to die sometime and from something." To such smokers the physicians' armamentarium need not be without response, for he has at his command quite solid epidemiologic evidence that mortality related to smoking is premature mortality. The evidence is available in two
'Professor and Head, Division of Epidemiology, School of Public Health, University of Minnesota, Minneapolis, hlinn.
Source: Vital Statistirs of the {J.S., 1867, vol. 11, Mortality, Part A.6
Table 1-Mortality front Selected Chronic Diseases Related t o Tobacco Smoking, United States, 1967 Sumbcr deaths
Diseases
Causally related: 54,407 Canrer of lung, bronrhus, trachea (162,163) Chronic 1)ronrhitis and emphysema (501,502,527.1) 26,181 Cancer of larynx (161) 2,707 143 Cancer of lip ( 140) Prohably causally related: Coronary heart disease (420) 573,153 8,563 Cancer of bladder ( 1 81.0) Cancer of buccal cavity and pharynx (141-148) 6,575 Cancer of esophagus (150) 5,627 Possil)ly causally related: Cerebrovascular disease (330-334) 202,184 Aortic aneurysm (451) 11,621 801,251
Total Total mortality, all causes
1,851,323
-
LEONARD M. SCHUMAN Table 2-Loss
in Life Expectancy ( i n years and as a percentage of total life expectancy of non-smokers) at Various Ages for Cigarette Smokers Hammond Study US., 19677
Numlwr of Cigarettes Smoked per Day 1-!)
Age
Ye:w I~0kt
25 years 30 years 35 years 40 years 45 years 50 yc,ars 55 years 6(! years 6.5 years
4.6 4.6 4.5 4.3 4.1 3.8 3.5 3.1 2.8
10-19
%
Yc-ar Lost
9.5 10.5 11.5 12.5 13.7 14.8 16.4 17.6 19.9
5.5 5.5 5.4 5.2 5.0 4.6 4.0 3.5 2.9
forms: loss in life expectancy and excess mortality in the several pertinent age groups. Hammond, from the data on the U.S. men in his 25-state study, utilizing the life expectancy of the men who never smoked regularly as the standard, was able to calculate the loss in life expectancy at various ages among the regular cigarette smokers. Table 2 presents these data.7 In any single age group the percentage of life expectancy lost among smokers increases with the amount of cigarettes smoked per day; and at any level of smoking the percentage of life expectancy lost increases with age. However, from these data it can readily be seen that the greater absolute number of years lost in life expectancy occurs among the younger age groups for any level of smoking. Both the Dornh study of veterans and the Hammond!' study of over 1,000,000 men and women in 25 states provided data for Horn's calculations of excess deaths among smokers as percentages of total mortality in the relevant age and sex groupse3 Excess deaths among smokers were the number of deaths over and above those which would have occurred if smokers had the same death rates as those who never smoked regularly. Although there is an excess mortality among cigarette smokers in each age group, Horn's calculations reveal these smoking-related excesses to be proportionately higher for the younger age groups. In both studies the male excess smoker mortality was proportionately greatest in the 45-54 year age group. This excess was 43 and 38 percent respectively of the total mortality in this age group. The second highest proportionate excess was in the 35-44 year age group (33 percent in both studies.) In the age groups beyond 54 years the proportionate excesses declined progressively. Women smokers in the Hammond study also experienced their highest proportionate excess mor-
40 and over
20-39
Years Lost
%
Years Lost
%
tality in the 45-54 year age group. This excess was of a lower magnitude than for the men, but was still a significant 9 percent of their total age-specific mortality. Thus, the impact of smoking-related mortality is felt predominantly in the prime years of life for both men and women. This is evidence enough to appeal to man's evocable, albeit subconscious, striving for a measure of immortality. We must, in turn, not overlook a possibly more immediate patient concern and that is illness which disables for longer or shorter periods, which reduces his productivity and restricts even his more or less spiritual activities-in short, which reduces the quality of life for him and his family. Information on excess morbidity related to smoking has become available through periodic inquiries on smoking among those in the probability samples of the ongoing National Health Survey.1" In this survey, disabling illness has been measured in three ways: days lost from work, days in which activity has been restricted, and days confined to bed. For all three types of disability and for both men and women, higher morbidity ratios, greater morbidity rates and higher percentages of excess disability days are found among cigarette smokers." As with mortality, excess disability days among smokers of cigarettes is greater, proportionately, in the relatively younger age groups. Among men smokers, the 45-64 year age group reported the highest excess morbidity-a 28 percent excess of disabling illness by each of the three morbidity measures. The 17-44 year age group was next with a 20-23 percent excess. Among women smokers, disabling illness occurred in highest excess in an even younger age group-those 17-44 years of age-with the age group 45-64 showing the next highest morbidity excess. The National Health Survey also provides data on prevalence of chronic conditions among smokers and non-smokers. It is of further interest not only CHEST, VOL. 59, NO. 4, APRIL 1971
BENEFITS OF CESSATION OF SMOKING that the smokers have higher prevalence rates of chronic conditions, but that the excess prevalence of such chronic conditions among young smokers ( 1744 years of age) is proportionately higher than for all older age groups.1" This is true for both men and women. For both the three measures of disability and the prevalence rates of chronic conditions a dose-eflect gradient with amount of cigarettes smoked per day was demonstrated. It is thus quite apparent that smoking is also strongly related to prematurely disabling illness. Despite these evidences of the gravity and magnitude of the problem the physician will frequently share the pessimism of the long-time smoker, the heavy smoker who questions the value of cessation of smoking-who himself states "I've been smoking so long, the damage has been done. \Vhat can be gained by stopping?" Data from the prospective studies would tend to refute this pessimism for these reveal repeated evidences of advantageously lower risks of mortality among smokers who have discontinued the habit than among continuing smokers. In the first portion of Table 3, general mortality among smokers and ex-smokers of cigarettes is expressed as a ratio relative to mortality in non-smokers. For each of the five studies in which the classes of smokers could be separated, excigarette smokers had distinctly lower risks than continuing smokers. Of importance to the skeptical patients who believe that their situation is hopeless for having smoked excessively for a great number of years is the reduction in mortality risk noted in several studies after cessation of smoking."ven if the patient has smoked more than a pack a day for 2.535 years, his risk of death is materially reduced. Even if he has smoked more than a pack a day, very significant gains are apparent if he quits at ages 4554. If he smokes no more than a pack a day then, even at ages over 55, significant reduction in risk is evident. If he remains a discontinued smoker for five to ten years, his risk of death is reduced almost to that of one who has never smoked.'' Gains in reduction of disease-specific mortality by cessation are even more dramatic for several of the specific entities associated with cigarette smoking. Even with the relatively short term followup data available during the evaluation of the prospective studies for the Advisory Committee's Report to the Surgeon Genera1,Z significant reductions in risk on cessation of smoking had been noted for all but one of the several diseases associated with cigarette smoking. Chronic bronchitis and emphysema mortality was actually higher among ex-smokers than current cigarette smokers. (This was a phenomenon
CHEST, VOL. 59, NO. 4, APRIL 1971
also noted in the total mortality rates for discontinued pipe and cigar smokers at that time.) Since the data on ex-cigarette smokers were generally not adjusted for duration of discontinuance or for reasons for discontinuance ( e g doctor's orders or severity of already-existing illness) this apparent discrepancy in an opposite direction was probably an artifact. Actually, it can be shown by more recent data derived from longer term follow~ ~ reduction in risk up in at least two s t u d i e s s ~that of mortality from chronic bronchitis and emphysema does indeed occur with cessation of smoking cigarettes. Table 3 presents these recent data by specific prospective study and for specific disease entities. A remarkable consistency in the reduction of mortalTable 3--Comparison of Mortality Ratios of Ex-Cigarette S n ~ o k e r swith Current Cigarette Smokers
Entity Total hlortnlity (2): British physicians (Doll and Hill) hlen in 9 States (Hammond and Horn) U.S. veterans (Dorn) Canadian veterans (Best et al) Men in 25 states (Hammond) Cause-Specific hlortality: Lung Cancer U.S. veterans (Dorn) (8) 25 states (Hammond) (9) Canadian veterans (Best et al) (13) British physicians (Doll and Hill) (14) Chronic Bronchitiv and Emphysema U.S. veterans (8) British physicians (14) Cancer of Laryw (2) Cancer of Oral Catrily U.S. veterans (8) Cancer of Eeophapua U.S. veterans (8) Cancer oj Bladder U.S. veterans (8) Coronary Heart Disease U.S. veterans (8) 25 states (11) British physicians (14) Cerebrovascular Disease U.S. veterans (8) 25 states (11)
Aortic Aneurysm (non-syphilitic) U.S. veterans (8) Cirrhosis of the Liver U.S. veterans (8)
1-19ciga/day 20+
1.44 1.70 1.79 1.65 1.83
1.04 1.40 1.41 1.42 1.50
12.1 6.5 13.7
5.0 2.0 7.9
(& ::::) 17.3 17.4
a
i
d
a
6.1
3.4
10.1 11.6 7.1
7.6 7.6 5.4
4.1
2.1
6.2
1.6
2.2
1.6
1.7 1.9 2.6 1.4
1.3 1.2 1.3 1.1
1.5 1.5 1.9
1.2 1.0 0.9
5.2
3.0
3.3
1.1
LEONARD M. SCHUMAN
ity ratios among ex-cigarette smokers for each specific disease is apparent among the several studies. The extension of the studies over a longer period of followup minimized the impact of the earlier higher mortality among those who discontinued smoking because of severe illness. In the U.S. veterans study, with the largest number of accumulated deaths (over 46,000) of any of the prospective studies, the volume of the data and the foresight of the investigator permitted the development of a subcategory of discontinued smokers who stopped smoking for reasons other than "doctor's orders." The data on ex-smokers of cigarettes derived from the U.S. veterans study are for this category of discontinued smokers.8 In the most recent analyses of the Hammond 25state data, the investigators confined themselves to the study of the approximately 80 percent of their subjects who, at the time of enrollment, had no history of heart disease or stroke, no history of cancer diagnosed within the preceding five years and were not sick.11 In this manner smokers who had discontinued smoking because of ill health prior to the time of enrollment were excluded. It is noteworthy that the greatest reductions in risk are to be found for the cancers associated with cigarette smoking. This is not surprising when it has been noted that the greater the magnitude of the relative risk the more likely that cigarette smoking is the principal causal factor in the disease. Lower relative risks imply other related factors may also be causally operating. Because of the relatively small mortality ratios observed for coronary heart disease, the magnitude of the gains from cessation of smoking cigarettes may be inapparent on superficial inspection. Cornfield and Mitchell12 hold a conservative attitude with regard to the degree of decrease in risk with smoking discontinuance. They cite the persistence of some coronary mortality effect after at least a decade of discontinuance of smoking, but do acknowledge significant reductions in risk. Because of the magnitude of the coronary heart disease
problem, what appears as a small reduction in ratio is a highly significant reduction in absolute death rates from this cause. Table 4 demonstrates this point. The differences between the rates for current smokers and for ex-smokers represent the gains for the specific levels of smoke exposure and for the several age groups. As an illustration, in the 55-64 year age group, discontinued smokers who had smoked more than two packs of cigarettes per day achieved a coronary heart disease mortality risk level which was 455 deaths per 100,000 less than those who continued to smoke at that dose-rate. This latter smoking group experienced a coronary heart disease mortality rate of 1101 per 100,000. Thus, a 41 percent reduction in mortality risk is. certainly meaningful. This can also be seen in the 25-state study of Hammond with respect to the length of time smoking of cigarettes had been discontinued and the level of smoking which had prevailed prior to such discontinuance. In Table 5 it can be seen that, for both levels of smoking, the longer the discontinuance, the greater the reduction in risk, and after ten years the risk is, respectively, equal to or almost equal to that of those who never smoked. Since there continue to be those who would refute these data with the charge of selective bias, nature has obligingly produced a situation similar to a controlled cessation experiment. In England and Wales, a considerably large reduction in cigarette smoking among physicians followed upon the first Doll and Hill report in 1954, whereas among the general population, cessation of smoking was not a common phenomenon. In the general population, increases in mortality from lung cancer and cardiovascular diseases have taken place in the 10- to 11year period following this report. Whereas the lung cancer mortality in the general male population, aged 35-84, increased from 1.49 to 1.86 per 1000 population per year between the periods 1954-57 and 1962-64, an increase of 25 percent, the lung cancer mortality among the same-aged British physicians actually declined from 1.09 to 0.76 per 1000
Table 4--Annual Death Rate per 100,000 from Coronary Heart Disease b y Age, Cigarette-Smoking Status and Number of Cigmettes Smoked per Day, U.S. Veterans Study ( 8 )
Number smoked per day1 1 to 9
10 to 20 21 to 39 40
+
Current cigarette smokers 195 297 390 502
45-54
Exsmokers2
Current cigarette smokers
125 133 57 -
594 830 912 1,101
55-64
Exsmokers2
Current cigarette smokers
432 557 743 646
1,374 1,577 1,701 1,955
65-74
Exsmokers2 1,105 1,200 1,366 1,482
IThis is the current rate of smoking for current cigarette smokers and the maximum rate attained for ex-cigarette smokers. 2Ex-smokers who stopped for reasons other than doctor's orders.
CHEST, VOL. 59, NO. 4, APRIL 1971
BENEFITS OF CESSATION OF SMOKING Table
5--Coronary Heart Disease ( M e n ) . Age-Standardized Death Rates for Ex-Cigarette Smokers with History of Cigarette Smoking Only, by Former Number Smoked per Day and Years Since Last Cigarette Smoking. Death Rates for Current Cigarette Smokers with History of Cigarette Smoking Only and M e n W h o Never Smoked Regularly are Shown for Concparison. M e n Aged 50-69'"
Smoked 1-19 cigarettes a day Ex-rigarette smokers (years since last cbigarrtte smoking)
Xumber men
Number deaths
8,569 22,808 55,728
210 78 1 1,114
Smoked 20
Death rate
+ cigarettes a day
Sumber men
Number deaths
21,624 56,886 55,728
630 1,895 1,114
Death rate
Undcr 1 year 1 to 4 years 5 to 9 years 10+ years Total ex-smokers Current cigarette smokers Never smoked regularly
635 947 502
813 1,029 502
'Four or more but less than 10 deaths expected in some of the component 5 y e a r age groups.
population in the same period; a reduction of 30 p e r ~ e n t . 1Similarly, ~ whereas the total cardiovascular disease mortality among the general male population aged 35-64 increased 10 percent between the periods 1953-57 and 1961-65, mortality from these diseases actually declined by 6 percent among the British physicians.'" May I once more turn your attention from mortality to illness studies, for it is in this area of maintenance of health and alleviation of symptoms of disease that a more successful appeal to the smoker may probably be made. A large number of prospective studies in the United States and abroad have directed their attention to coronary heart disease incidence and morbidity. Notable among these in the United States are the studies at Framingham, Massachusetts and Albany, New York; the Peoples Gas and Light Co. and Western Electric Co. studies in Chicago, Illinois; the fivecounty study in North Dakota; the Western Collaborative Study; the Health Insurance Plan Study in New York City; the Los Angeles Heart Study; and the Tecumseh, Michigan, Study. The prospective and retrospective studies of Dorken, Friedmann, and Schimmler, respectively, in Germany, Mulcahy in Ireland, Medalie in Israel, Hyams in Japan, Natvig in Norway and Heyden-Stucki in Switzerland are also of significant note. From among these studies several have gathered sufficient data permitting analyses of incidence rates for current and discontinued smokers. Table 6 reveals the decline in risk with discontinuance of cigarette smoking in three prospective studies. In the Western Collaborative Group Study this decline was significant for the 50-59 year age group only. In the younger age group the risk among discontinued smokers was approximately the same as for the continuing moderate to heavy smokers. However, since no information is available on reasons for discontinuance nor length of time of such disconCHEST, VOL. 59, NO. 4, APRIL 1971
tinuance, the meaning of this lack of difference in the younger age group cannot be determined. Morbidity from bronchopulmonay entities is probably most evident to the smoker even if he is suffering from relatively mild pathology such as a chronic productive cough. Furthermore, it is with this group of disease entities that remarkable diminution or disappearance of symptoms follow rapidly after cessation of smoking. We are indebted to the National Health Survey for data on the prevalence of chronic bronchitis and/or emphysema among smokers of cigarettes, non-smokers and ex-smokers.10 Among young men aged 17 years and over, ex-smokers revealed an ageadjusted prevalence rate of 2.5 cases per 100 as compared with 3.3 cases for current smokers of Table M o m p a r i s o n
of Risks of Developing Coronary Heart Disease Among Continuing and Ex-Smokers of Cigarettes
Study (Reference)
Relative Risk (non-smoker = 100) Current ExCigarette Cigarette Smokers Smokers
Framingham and Albany!'' <20 cigs/day 20 cigs/day >20 cigs/day
179 185 274
North Dakota Is*
22 1
107
Western Collaborative Group 19** a ) 39-49 year age group: 1-15 cigs/day 16-25 26
142 247 272
1 } 258 i
124 188 228
} 1
+
b)
50-59 year age group: 1-15 cigs/day 16-25 26
+
!
I
) 107
1
104
*Myocardial infarction only. **All coronary heart disease. Calculated from authors' data.
LEONARD M. SCHUMAN more than a pack per day. Among women, the ageadjusted prevalence for ex-smokers was 2.6 cases per 100 as compared with rates of 4.0 per 100 for smokers of one-half to one pack a day and 6.5 per 100 for smokers of more than a pack a day-an even more favorable reduction in risk. These data of the National Health Survey are of special interest, since it is entirely likely that the real effects of cessation of smoking may in part be masked by the possibly greater tendency for discontinuance among those disabled by severe bronchopulmonary disease. When one turns to symptoms and pulmonary function tests rather than finite diagnoses with their difficulties of definition, the benefits of cessation are more readily discernible. A number of surveys have demonstrated much lower proportions of individuals with chronic cough and with phlegm among exsmokers than among those continuing cigarette smoking-proportions which approach the prevalence in non-smokers. One such study of a total regional population in Finland by Huhti20 provides the data for Table 7 which is illustrative of many. Markedly lower prevalences of cough and phlegm among men ex-smokers are noted even in comparison with the continuing smokers of small numbers of cigarettes per day. Similar contrasts are noted for women ex-smokers, but the continuing smokers of 15 or more cigarettes per day among women were too few for a statement of significance. Coates et al,*l in their study of Detroit postal workers, found the ex-smokers to have prevalences of chronic cough and phlegm equal to that of nonsmokers. Holland,22 in a study of van-drivers in London and rural towns in England and in East Coast towns of the United States, found the proportions with chronic cough and phlegm among exsmokers of cigarettes much closer to that in nonsmokers than among even the continuing light smokers (from 1-14 cigarettes per day) of cigarettes. Table 7-Percent of Men and Women with Cough ( 3 months in the year) and with Phlegm ( 3 months in the year) Related to Smoking Habits ( 2 0 ) Cigarettes smoked per day Cough : Men Women
25+
N ~ ~ E- ~ smokers smokers
1-14
15-24
31.5 10.4
40.8 42.4 (3 of 7 women smoking 15+
4.1 4.5
8.5 13.3
42.9 42.4 (4 of 7 women smoking 15+
10.7 5.9
17.7 13.3
rigarettes/day
Phlegm : Men Women
38.0 10.4
cigaret tes/dav
In some of these prevalence studies pulmonary function tests accompanied the medical questionnaires. Here also the ex-smoker of cigarettes showed values for 1-second forced expiratory volume and peak expiratory flow rates significantly higher than those for continuing smokers and almost as high as the values for non-smokers.*0.2:{ Evidences from these cross-sectional studies suggest the inference that cessation of cigarette smoking in the individual brings improvement in pulmonary function and diminution or eradication of chronic respiratory symptoms. Support for such an inference is found in longitudinal studies which reexamined the same subjects at a reasonable interval of time. The studies by Higgins and associates,"" Holland and Elliott,*-' and Fletcher" are examples of note. More recently Comstock and his co-workers,20 in a study of men telephone company employees re-examined after a five-year interval, found marked improvement in the prevalence of cough and phlegm among those who had quit smoking cigarettes between the two surveys. Furthermore, though FEV1 values for all smoking classes declined between examination rounds, the ex-smokers of cigarettes showed the smallest decline and thus more closely approached the value for the nonsmokers. Experimental evidence also supports these findings. The studies of Krumholz et al," with smoking subjects who abstained for six weeks, revealed significant increases in peak flow rates, diffusing capacity, inspiratory reserve volume and maximal voluntary ventilation. Heart rate, oxygen debt after exercise and functional residual capacity was decreased. Wilhelmsen" demonstrated marked decreases in coughing, sputum production and wheezing in a group of long term smokers who abstained from cigarette smoking for 40 days. A significant increase in FEVl.o also occurred. Peterson and coworkers*!) similarly demonstrated significant increases in pulmonary function and decreases in coughing and breathlessness among smokers of cigarettes after 18 months of abstinence. Finally, autopsy materials on discontinued smokers reviewed by Auerbach et a13" reveal changes in the tracheobronchial tree (such as loss of cilia, basal cell h~perplasiaand atypical cells) in quantitative proportions more nearly like that of non-smokers as opposed to moderate or heavy smoker patterns. Similarly, these same investigators found a lesser degree of pulmonary fibrosis, rupture of alveolar septa and thickening of the walls of small arteries and arterioles in the pulmonary parenchyma of individuals who had stopped smoking cigarettes for five years or more than among current smokers.:!'
,,
CHEST, VOL. 59, NO. 4, APRIL 1971
BENEFITS OF CESSATION OF SMOKING Thus, there is good evidence of reversal of bronchitic changes and some intimation of reversal of parenchymal change or at least arrest. In summary, it can be said with great optimism that cessation of smoking does indeed reverse a number of processes and arrest others, short of morbidity or, at worst, premature mortality. To the benefits in terms of reduction of disease and disability must be added the increase in comfort, the feeling of well-being and positive health, not to mention the esthetic gains of a fresh smelling breath and a clear atmosphere. This optimism can and must be carried into office practice and communicated as prognosis to the scoffing young smoker and the inveterate older chronic smoker.
1 Royal College of Physicians of London: Smoking and Health. Summary and Report on Smoking in Relation to Cancer of the Lung and other Diseases. London, Pitman, 1962 2 U. S. Public Health Service: Report of the Advisory Committee on Smoking and Health to the Surgeon General. PHs Publication No. 1103, U. S. Government Printing Office, Washington, D.C., 1964 3 U. S. Public Health Service: The Health Consequences of Smoking. A Public Health Service Review: 1967. PHs Publication No. 1696, U. S. Government Printing Office, Washington, D.C., 1967 4 U. S. Public Health Service: The Health Consequences of Smoking: 1968 Supplement to the 1967 Public Health Service Review. PHs Publication No. 1696-1, U. S. Government Printing Office, Washington, D.C., 1968 5 U. S. Public Health Service: The Health Consequences of Smoking: 1969 Supplement to the 1967 Public Health Service Review. PHs Publication No. 1696-2, U. S. Government Printing Office, Washington, D. C., 1969 6 U. S. National Center for Health Statistics: Vital Statistics of the United States, 1967. Yiortality, Vol. 11, Part A, U. S. Government Printing Office, Washington, D.C., 1969 7 Hammontl EC: Life expectancy of American men in relation to their smoking habits. In Summary of the Proceetlings of World Conference on Smoking and Health, National Interagency Council on Smoking and Health, New York City, September 11-13, 1967 8 Kahn HA: The Dorn sh~clyof smoking and mortality among U. S, veterans: report on 8%years of observation. In: Haenszel W, editor. Epidemiological Approaches to the Study of Cancer and other Diseases. Bethesda, U. S. Puhlic Health Service, National Cancer Institute Monograph No. 19, January 1966 9 Hammond EC: Smoking in relation to the death rates of one million men and women. In: Haenszel W, editor. Epidemiological Approaches to the Study of Cancer and other Diseases. Rethesda, U. S. Public Health Service, National Cancer Institute Slonograph No. 19, January 1966 10 U. S. Public Health Service: National Center for Health Statistics. Cigarette smoking and health characteristics, United States, Jt~ly1964 to June 1965. Vital and Health Statistics series 10, No. 34, U. S. Public Health Service Publication No. 1000, Washington, D. C., Xlay 1967
CHEST, VOL. 59, NO. 4, APRIL 1971
11 Hammond EC, Garfinkel L: Coronary heart disease, stroke, and aortic aneurysm. Arch Environ Health 19: 167182, 1969 12 Cornfield J, Mitchell S: Selected risk factors in coronary disease. Possible intervention effects. Arch Environ Health 19:382-394, 1969 13 Best EWR: A Canadian study of smoking and health. Department of National Health and Welfare, Ottawa, 1966 14 Doll R, Hill AB: llortality in relation to smoking: 10 years observation of British doctors. Brit hled J 1 (5395) : 1399-1410 and 1 ( 5396) : 1460-1467, 1964 15 Doll R: Cancer bronchique et tabac. Bronches (Paris) 16:313-324, 1966 16 Fletcher CM, Horn D : Smoking and health. WHO Chronicle 24:345-370, 1970 17 Doyle JT, Dawber TR, Kannel WB, et al: The relationship of cigarette smoking to coronary heart disease. JAhlA 190:886-890, 1964 18 Zukel WJ, Lewis RH, Enterline PE, et al: A short-term community study of the epidemiology of coronary heart disease. Amer J P H 49:1630-1639, 1959 19 Jenkins CD, Rosenman RH, Zyzanski SJ: Cigarette smoking. Its relationship to coronary heart disease and related risk factors in the Western Collaborative Group Study. Circulation 38: 1140-1155, 1968 20 Huhti E: Prevalence of respiratory symptoms, chronic bronchitis and pulmonary emphysema in a Finnish rural population. Acta Tuherculosea et Pneumologica Scandinavica ( Kobenhavn) Supplementum 61, 1965 21 Coates EO Jr, Bower GC, Reinstein N: Chronic respiratory disease in postal employees. JAhlA 191 : 161-166, 1965 22 Holland WW, The natural history of chronic bronchitis. J College of General Practitioners 11: Supp. 2:8-16, 1966 23 Higgins ITT, Gilson JC, Ferris BG, et al: Chronic respiratory diseases in an industrial town: A nine year follow-up study. Amer J Public Health 58: 1667-1676, 1968 24 Holland WW, Elliott A: Cigarette smoking, respiratory symptoms and anti-smoking propaganda. An experiment. Lancet 1:41-43, 1968 25 Fletcher ChZ: Bronchial infection and reactivity in chronic bronchitis. J Roy Coll Phys Lond 2: 183-190, 1968 26 Comstock GW, Brownlow WJ, Stone RW, et al: Cigarette smoking and changes in respiratory findings. Arch Environ Health 21:50-57, 1970 27 Kmmholz RA, Chevalier RB, Ross JC: Changes in cardiopuln~onaryfunctions related to abstinence from smoking. Ann Int Med 62: 197-207, 1965 28 Wilhelmsen L: Effects on bronchopulmonary symptoms, ventilation and lung mechanics of abstinence from tobacco smoking. Scandinavian J Resp Dis 48:407-414, 1967 29 Peterson DI, Lonergan LH, Hardinge hlG: Smoking and pulmonary function. Arch Env Health 16:215-218, 1968 30 Auerbach 0 , Stout AP, Hammond EC, et al: Changes in bronchial epithelium in relation to sex, age, residence, smoking and pneumonia. New Eng J l l e d 267: 111-119, 1962 31 Ar~erbach0 , Stout AP, Hammond EC, et al: Smoking habits and age in relation to pulmonary changes. Rupture of alveolar septums, fibrosis and thickening of walls of small arteries and arterioles. New Eng J Med 269: 10451054, 1963 Reprint requests: Dr. Schuman, 1158 Mayo hle~norialBuilding, University of Minnesota, Minneapolis 55455.