PART |

Current Information on the
Health Consequences of
Smoking

 
Highlights of The Report

 

General Mortality Information

Previous findings reported in 1967 indicate that cigarette smoking 1s
associated with an increase in overall mortality and morbidity and
leads to a substantial excess of deaths in those people who smoke. In
addition, evidence herein presented shows that life expectancy among
young men is reduced by an average of 8 years in “heavy” cigarette
smokers, those who smoke over two packs a day, and an average of 4
years in “light” cigarette smokers, those who smoke less than one-half
pack per day.

Smoking and Cardiovascular Diseases

Current physiological evidence, in combination with additional
epidemiological evidence, confirms previous findings and suggests ad-
ditional biomechanisms whereby cigarette smoking can contribute to
coronary heart disease. Cigarette smoking adversely affects the inter-
action between the demand of the heart for oxygen and other nutrients
and their supply. Some of the harmful cardiovascular effects appear
to be reversible after cessation of cigarette smoking.

Because of the increasing convergence of epidemiological and physi-
ological findings relating cigarette smoking to coronary heart disease,
it is concluded that cigarette smoking can contribute to the develop-
ment of cardiovascular disease and particularly to death from coro-
nary heart disease.

Smoking and Chronic Obstructive Bronchopulmonary Diseases

Additional physiological and epidemiological evidence confirms the
previous findings that cigarette smoking is the most important cause
of chronic non-neoplastic bronchopulmonary disease in the United
States.

Cigarette smoking can adversely affect pulmonary function and
disturb cardiopulmonary physiology. It is suggested that this can lead
to cardiopulmonary disease, notably pulmonary hypertension and cor
pulmonale in those individuals who have severe chronic obstructive
bronchitis.
Smoking and Cancer

Additional evidence substantiates the previous findings that ciga-
rette smoking is the main cause of lung cancer in men. Cigarette smok-
ing is causally related to lung cancer in women but accounts for a
smaller proportion of cases than in men. Smoking is a significant factor
in the causation of cancer of the larynx and in the development of can-
cer of the oral cavity. Further epidemiological data strengthen the
association of cigarette smoking with cancer of the bladder and cancer
of the pancreas.
Smoking and Overall Mortality

 

The 1964 Advisory Committee’s Report (3) clearly and em-
phatically outlined the dangers of cigarette smoking to health. The
conclusions of the Committee, as outlined in the 1967 Report (2), were
as followst

CIGARETTE smoking is associated with a T0-percent increase im
the age-specific death rates of males, and to a lesser extent with in-
creased death rate 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 nonsmokers. For those who
smoke from 10 to 19 cigarettes a day, it is about 70 percent higher than
for nonsmokers: 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.

In two studies which recorded the degree of inhalation, the mor-
tality ratio for a given amount of smoking was greater for inhalers
than for noninhalers.

The ratio of death rates of smokers to that of nonsmokers is highest
at the earlier ages (40-50) represented in these studies, and declines
with increasing age.

Possible relationships of death rates to 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 nonsmokers. For men
smoking more than 5 cigars daily, death rates are slightly higher.
There is some indication that these higher death rates occur primarily

5
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 nonsmokers, even for men who smoke 10 or
more pipefuls a day and for men who have smoked pipes more than
30 years,

In fact, the Committee’s concern was of such an immediate nature
that they recommended; “* * # appropriate remedial action.”

The 1967 report reviewed the literature of the 314 years subsequent
to the 1964 report and found no evidence to refute the conclusions of
the latter,

Additional evidence was given which clarified some of the patho-
biomechanisms of the diseases associated with smoking. The findings
of the 1964 report were strengthened and some new ones stated. New
data on the general mortality and morbidity associated with smoking
were presented. The highlights of the 1967 report are given below:

1. The previous conclusions with respect to the association hetween
smoking and mortality are both confirmed and strengthened by the
recent reports. The added period of followup and analysis of deaths
of nonrespondents as well as of respondents in the Dorn Study sug-
gests that the earlier reports may have understated the relationship.

2. More information is now available for specific age groups than
previously, A comparison of three ways of measuring the relationship
indicates that cigarette smoking is most important among men aged
45 to 54 both in terms of mortality ratios and excess deaths expressed
is a pereentage of total deaths. Nevertheless, uthough both of these
measures decline with advancing age, the increment added to the death
rate, which reflects one’s personal chances of being affected, continues
to increase with age. For men between the ages of 35 and 59, the
excess deaths among eurrent cigarette smokers account for one out
of every three deaths at these ages, For women, with their lower oyer-
ull exposure to cigarettes, the comparable figure is about one death out
of every 14 at ages 35 to 59,

3. Women who smoke elgarettes shaw slenifieantly elevated death
rates over those who have never smoked regularly. The magnitude of
the relationship varies with xeveral measures of dosage. By and large
the same overall relationships between smoking and mortality are
observed for women as had previously been reported for men, but at
a lower level. Not only are the death rates for men who have never
smoked reewlarly higher than those for women who have never smoked
regularly, but the effect of smoking as measured either by differences in
death rates or by mortality ratios is greater for men than for women.
At Teast part of this can be accounted for by the lower exposure of
female cigarette smokers whether measured by number of cigarettes,
duration of smoking, or degree of inhalation,

4. Previous findings on the lower death rates among those who hare
discontinued cigarette smoking are confirmed and strengthened by the
additional data reviewed. Kalu's analysis of ex-smokers in the U.S,
veterans study—controlling for age at which they began snioking,
‘unount smoked, and current ige—reveals a downward trend in risk
relative to those who continued to smoke as the duration of time dis-
continued increases. The British physician study, in which a down-

 

6
ward trend is reported in lung cancer death rates for the entire group
(smokers, ex-smokers, and those who never smoked, combined) along
with a very sharp reduction in cigarette smoking by the physician,
is the best. available example of a controlled cessation experiment with
reduction of risks resulting from reduction of smoking. The findings
of this report support the view that epideniological data showing
lower death rates among former smokers than among continuing
smokers cannot be dismissed as due to selective bias and that the bene-
fits of giving up smoking have probably been understated.

5. Cigarette smokers have higher rates of disability than nonsmok-
ers, whether measured by days lost from work among the employed
population, by days spent ill in bed, or by the most general measure
—days of “restricted activity” due to illness or injury, Data from the
National IHealth Survey provide a base for estimating that in 1 year
in the United States an additional 77 million man-days were lost from
work, an additional 88 million man-days were spent ill in hed, and
an additional 306 million man-days of restricted activity were experl-
enced because cigarette smokers have higher disability rates than non-
smokers. For men age 45 to 64, 28 percent of the disalility days ex-
perienced represent the excess associated with cigarette smoking.

In the 1967 Report the following questions were emphasized :

1. How much mortality and excess disability are associated with
smoking ?

2, How much of this early mortality and excess disability would
not have oceurred if people had not taken up cigarette smoking?

3. Tow 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 eritical factors in these mechanisms?

The problem of how best to measure the relationship between smok-
ing and mortality was presented by three meaningful measures of
comparison :

1. Mortality Ratios: Obtained by dividing the death rate for a clas-
sification of sinokers by the death rate of a comparable group of non-
smokers * * * A mortality ratio has been considered to reflect the
degree to which a classification variable identifies or may account for
variations in death rates. As such, it isa mensure of relative risk which
indicates the importance of that variable relative to uncontrolled vari-
ables—an indicator of potential biological significance,

2. Differences in Mortality Rates: Obtained by subtracting from
the death rate for smokers, the death rate of a comparable group of
nonsmokers * * *, This measure reflects the added probability of
death in a 1-year period for the smoker over that for the nonsmoker.
As such it is a measure of personal health significance, a means for
the individual to estimate the added risk to which he is exposed.

3. Excess Deaths: Obtained by subtracting from the number of
deaths occurring in a group of smokers, the number of deaths which
would have ocenrred if that group of smokers had experienced the
same mortality rates as a comparable group of nonsmokers. In the
example which follows this has been reported as a percentage of all

315-131 O—68—__2 7

 
TapiE 1.—Comparison of mortality rates for smokers and nonsmokers
by age and ser: Based on data from U.S. Veterans Study and
Hammond Study

 

 

 

Study population, sex, and measure of | 35-44 45-54 | 55-64 | 65-74 75-84
mortality | years years years years years
U.S. VETERANS: MEN
Total number of deaths- ----- 383 366 | 13, 840 | 17, 550 | 1, 932
Death rates per 100,000:
Never smoked regularly -- - - ---- 127 264 1,056 | 2,411 | 6, 214
Current cigarette smokers- --- -- 232 728 1, 819 4,032 | 8,471

Mortality ratio 1_._._-------------
Difference in death rates per

 

193} 276) L72| 167 1. 36

100,000 ?___.-_----------------- 105 464 763 1, 621 | 2, 257
Excess deaths as pereentage of
total 3._._-....------------------ 33 43 21 17 8

Hammond MEN

Total number of deaths- --- -- 631 5,297 | 8, 427 8, 125 | 3, 968
Death rates per 100,000: | |
Never smoked regularly--. ------ 210 | 406 1, 202 | 3, 168 | 7, 863
Current cigarette smokers------! 397 | 925 | 2, 202 4, 788 9, 674
Mortality ratio !_.---------------- 1. 89 2.28 | 1.83 1. 51 1. 23
Difference in death rates per | | |
100,0002.......----------- = 187 519 | 1,000. 1,620! 1,811
Excess deaths as percentage of | | | |
total 3.__._.._------------------ | 33 38 25 13 | 4
HamMMOND WOMEN | | | |
Total number of deaths---- -- 727, 2,826 3,915, 3, 115 | 4,188
Deaths rates per 100,000: | |
Never smoked regularly-------- 165 304 | 69S 1,913 : 5, 914
Current cigarette smokers_._- -- | 186 384 | S38 | 2, 229 5, 846
Mortality ratio !_..--------------- 113; 1.26 1.20: 117) .99
Difference in death rates per | | |
100,0002_..----------- 2-2 21 | so} 104 | 316) 68

Excess deaths as percentage of

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1 Mortality ratios—death rate fer current cigarette smokers divided by death rate for those who never
smoked regularly.

2 Differences in death rates—death rate for current cigarette smokers minus death rate for those who never
smoked regularly.

3 Excess deaths among current cigarette smnokers (i.e., additional deaths that oceurred among current
cigarette smokers per year above those which would have occurred if smokers had the same death rates as
those who never smoked regularly). This is expressed as a percentage of all deaths oceurring in that age-sex
group.

Source: The Health Consequences of Smoking (2).
deaths in the appropriate age group * * *. It should be noted that
this measure not only depends on the differences in death rates be-
tween the smokers and the nonsmokers, but also on the proportion of
smokers in the group. Thus, even with a large difference in rates
between smokers and nonsmokers, a population with very few smok-
ers would have very few excess deaths. This measure is therefore an
indicator of the public health significance of the differences found
since it measures the number of people affected and therefore the
magnitude of the problem for society as a whole.

As seen in table 1, from the 1967 report, the magnitude of the prob-
lem is reflected in the statement:

Reviewing both study groups it appears that for men between the
ages of 35 and 60 approximately one-third of all deaths that occur are
excess deaths in the sense that they would not have oecurred as early
as they did if cigarette smokers had the same death rates as the non-
smoking group. For women, the percentage is much lower, reaching
a peak of 9 percent of all deaths in age group 45-54.

Another valuable measure of comparison was recently calculated
by Hammond (1), from his study of over 1 million men and women.
Life expectancy of men with respect to cigarette smokers and non-
smokers is shown in tables 2 and 3. The life expectancy for a two-pack
a day, or more, smoker at age 25 is 8.3 years less than that for the
corresponding nonsmoker. Men at age 35 and over, who smoke two
or more packs of cigarettes per day, have between 20 and 25 per cent
less life expectancy than their corresponding nonsmoking counter-
parts. Even “light” smokers, those who smoke less than 10 cigarettes
per day, have from 2.8 to 4.6 fewer years of life expectancy than cor-
responding nonsmokers.

TABLE 2.—Estimated years of life expectancy at various ages for males
in the United States, by daily cigarette consumption

 

 

 

 

 

Number of cigarettes
Never smoked per day
Age smoked _
regu-
larly 1-9 | 10-19 | 20-39 | 40 and
over
25 years__.-_-____-------------------- 48.6 | 44.0 | 43.1 | 42.4 40. 3
30 years_______-_._------------------- 43.9 | 39.3 | 38.4 | 37.8 35. 8
35 years__.--__----------------------- 39.2 | 34.7 | 33.8 | 33.2 31.3
40 years___._-._.--------------------- 34.5 | 30.2 | 29.3 | 28.7 26. 9
45 years_.________--------------------- 30.0 | 25.9 | 25.0 | 24.4 23. 0
50 years._.-_._----------------------- 25.6 | 21.8 | 21.0 | 20.5 19. 3
55 years_..____._-.-_----------------- 21.4 117.9 | 17.4 | 17.0 16. 0
60 years_.._._-__.-___-_----_----------- 17.6 | 14.5 | 141] 13.7 13, 2
65 years___-._. eee 14.1) 11.3 5 11.2; 11.0 10.7
|

 

 

 

Sovgce: Hammond, E. C. (1).
TABLE 3.—Loss in life expectancy at various ages for cigarette smokers
compared with nonsmokers

{Loss in years is also expressed as a percent of the total life expectancy of nonsmokers}

 

 

 

 

 

 

 

 

 

 

 

Number of cigarettes smoked per day
Age 1-9 10-19 20-39 40 and over
Years | Percent Years | Percent | Years Percent Years | Percent
lost | lost lost i lost
| |
25 years. .-.-------- 46, 95) 55/113) 62/128) 83] 17.1
30 years..___------- 4.6 | 10.5 5.5 | 12.5 6.1 ; 13.9 8.1 18.5
35 years.___._-.___- 45/115) 54;138/) 60 153] 7.9] 202
40 years___.__---_-- 4.3 | 12.5 5.2 | 15.1 5. 8 16. 8 7.6 22.0
45 years__.-_.___--- 4.1 | 13.7 5.0 | 16.7 5.6 | 18.7 7.0 23. 3
50 years___-_-------- 3.8 | 14.8 4.6 | 18.0 5.1: 19.9 6.3 24. 6
55 years____--__---- 3.5!164: 40/187: 44 ; 20.6 5.4 25. 2
60 years_-...------- 3.1°176 385/199 39 222) 44) 25.0
65 years_____----_-- 28 199; 29/206. 31, 22.0 3.4 24.1
on | |
Source: Hammond, E. C. (1).
REFERENCES

(1) Hamnonp, E. C. Life expectancy of American men in relation to their
smoking habits. Presented at the World Conference on Smoking and
Health, New York City, September 11-18, 1967. 23 pp.

(2) U.S. Pusitic HEALTH SerRvIcE. The Health Consequences of Smoking. A
Public Health Service Review: 1967. Washington, U.S. Department of
Health, Education, and Welfare, Public Health Service Publication No.
1696, 1967. 227 pp.

(3) U.S. Pustic Heatru Service. Smoking and Health. Report of the Advisory
Committee to the Surgeon General of the Public Health Service. Washing-
ton, U.S. Department of Health, Education, and Welfare, Public Health
Service Publication No. 1103, 1964. 387 pp.

10
PART II

 

Technical Reports on the
Relationship of Smoking
to Specific Disease Categories
CHAPTER 1

 

Smoking and Cardiovascular Diseases

Contents

Page
Introduction________..._..._---------------------------- 15
Conclusions of the 1964 Report____._----------------- 15
Highlights of the 1967 Report___--------------------- 15
Smoking and Coronary Heart Disease.___._....------------ 16
Coronary Heart Disease Mortality. ._-.._..-..--------- 16
Coronary Heart Disease Morbidity__--_..------------- 17
Relationships of Cigarette Smoking to Other Risk Factors_ 21
Age__..___._----------------------------------- 21
High Blood Pressure.___-.----------------------- 21
High Serum Cholesterol and Related Diet.__--_---- 22
Physical Inactivity -....-.--..------------------- 23
Sociological, Psychological and Personality Variables _ 24
Multiple Risk Factors____..--------------------- 28
Genetic and Constitutional Studies____..---------- 28
Influence of Smoking and Nicotine on Blood Lipids------ 30
Epidemiological Studies. ____--_------------------ 30
Experimental Studies—Animal___._._-..-_--.----- 30
Studies in Humans____..___.-------------------- 31
Studies on Thrombus Formation_____.------.--------- 32
Catecholamines_______.__._..------------------- 32
Blood Lipids__..__._.___.----------------------- 32
Cardiovascular Response to Smoking and/or Nicotine. __- 34
Experimental Studies____.__.-------------------- 34
Studies in Humans.____.__..__.----------------- 36

Human Myocardial Tissue Function in Relation to
Anoxia and to Carbon Monoxide_____..--------- 38

Glucose Metabolism and Possible Cardiovascular
Effects.........__.----.---------------------- 40

Additional Considerations Regarding Coronary Blood
Flow__...._..-_---222 eee ---- 41
Summary, Concept and Conclusion__._-_-------------- 42

13
Smoking and Cerebrovascular Diseases
Cited References.......-._...

14
INTRODUCTION

The primary purpose of the 1968 Supplemental Report is to review
the pertinent literature that has become available subsequent to the
1967 Report. Brief mention of the conclusions of the 1964 Report and
the highlights of the 1967 Report is made to facilitate an understanding
of the significance of the most recent information. The current research
findings should be considered in the perspective of the research evi-
dence previously presented in the 1964 (748) and 1967 (746) Reports.

Concivsions or THE 1964 Rerorr (748)

Male cigarette smokers have a higher death rate from coronary
artery disease than nonsmoking males, but it is not clear that the
association has causal significance.

Hienvicuts or rie 1967 Reporr (146)

1. Additional evidence not only confirms the fact that cigarette
smokers have increased death rates from coronary heart disease, but
also suggests how these deaths may be caused by cigarette smoking.
There is an increasing convergence of many types of evidence concern-
ing cigarette smoking and coronary heart’ disease which strongly
suggests that cigarette smoking can cause death from coronary heart
disease,

2. Cigarette smoking males have a higher coronary heart disease
death rate than nonsmoking males. This death rate may, on the
average, be 70 percent greater, and, in some, even 200 percent greater
or more in the presence of other known “risk factors” for coronary
heart disease. Female cigarette smokers also have a higher coronary
heart disease death rate than do nonsmoking females, although not
as high as that for males. In general, the death rates from this disease
Merease with amount smoked. Cessation® of cigarette smoking’ is
followed by a reduction in the risk of dying from coronary heart
disease when compared with the risk incurred by those who continue
tosmoke.

3. A greater frequency of advanced coronary arteriosclerosis is
noted in male cigarette smokers, especially in those who smoke
heavily.

4. Additional evidence strengthens the association hetween cigarette
smoking and cerebrovascular disease, and suggests that some of the
pathogenetic considerations pertinent to coronary heart disease may
also apply to cerebrovascular disease.

 

*Those who have stopped smoking cigarettes have a lower risk of dying from coronary
heart disease than those who continue to smoke,

15
SMOKING AND CORONARY HEART DISEASE
Coronary Heart DiskAse Morraurry

As in the past two decades, coronary heart disease in the United
States continues as the leading cause of death, being responsible in 1967
for 567,710 deaths or 31.0 percent of the total of 1,833,900 deaths.

Since age specific data are not yet available for 1967, table 1 shows
the number of deaths due to coronary heart disease and the death
rates per 100,000 persons by age for 1966.

TABLE 1.—Coronary heart disease deaths and death rates per 100,000
population, by age: United States, 1966

[Disease -ategory 420 in the ICD Manual, 1957]

 

 

Age Number of Death

deaths rates
Total_-.-_ 2.2228 573, 191 292. 7
Under 25 years... 2222 250 0.3
25-34 years... 1, 469 6.6
35-44 years__- 22! 12, 522 52. 0
45-54 years. --_ 2-88 45, 997 206. 3
55-64 years__-_- 99, 647 577.3
65-74 years_-_- 88 162, 555 | 1, 405, 2
75-84 years. _ 8! 171, 737 | 2,979.5
85 and over____.0-- wee eee eee 78, 854 | 7,015.5

Not stated__- 222-22 160 (X)

 

 

 

X—Not applicable.
SOURCE: Monthly Vital Statistics, National Center for Health Statistics (147).

These data illustrate the dramatic increase in death rates as age
advances, with the increase being particularly marked after age 45,
The death rates for coronary heart disease for men and women continue
to show a conspicuous difference. In 1966 it was 361.6 for males and
226.5 for females per 100,000 population.

While several studies of various aspects of the association between
coronary heart disease mortality and cigarette smoking have heen
reported during the past vear, the most significant studies of this
association are contained in the 1967 report,

The several new studies of various aspects of the association between
coronary heart disease mortality and cigarette smoking follow.

Friedman (46) reported a strong positive correlation between per
capita cigarette sales and coronary heart disease death rates by states.
The correlation is 0.76 when data only from those states with relatively
accurate information of cigarette consumption are analyzed. Related
factors such as urbanization or softness of the local water supply do
not explain this degree of association.

16
Other studies deal with the excess deaths associated with smoking.
Strobel, et al. (740) reported that among 3,479 Swiss physicians, over
40 percent of the excess deaths occurring over a 9-year period among
smokers was due to coronary heart disease.

In contrast to the study above and data from the United States in
which approximately one-half of the excess deaths associated with
smoking are attributed to cardiovascular causes (148), preliminary
data from Hirayama (65) show that the excess deaths in Japan associ-
ated with smoking were primarily explained by cancer of various sites.
Only 12 percent of the excess deaths were associated with cardio-
vascular causes. This prospective study of 265,118 adults over the age
of 40 encompassed a followup period of 15 months. Additional follow-
up by Hirayama should yield useful data with respect to smoking and
excess mortality from cardiovascular diseases in this Japanese popu-
lation group, particularly with regard to the younger adults in the
study.

Hyams, et al. (67), on the other hand, speculate that the apparent
increase in the occurrence of coronary heart disease among Japanese
males, especially under the age of fifty, may be due to a trend toward
Westernization in both diet and smoking habits among younger
Japanese men.

Hammond (54), in his prospective study of over 1 million men and
women, showed a positive relationship between the duration of the
smoking habit and coronary heart disease mortality. In the Framing-
ham Heart Study (77), no association was found bet ween the duration
of the smoking habit and the incidence of mortality from heart attacks
among men who were “heavy smokers” (more than one package of
cigarettes per day).

These discrepancies between the relationship of smoking to the
incidence of total coronary heart disease and mortality from acute
coronary heart disease may be accounted for, in part, by the differences
in population groups studied and by the possibility that duration of
smoking may have a greater association with the fatal forms of
coronary heart disease.

Kannel, et al. (70), in more recent. data from the Framingham
study, indicate that the fatal and more severe forms of coronary
disease are more strongly associated with cigarette smoking that the
less severe forms (figure 1).

Coronary Heart Disease Morbidity *

Much of the morbidity data reported during this past year resulted
from retrospective studies of patients or cross-sectional studies (106,
107, 127, 134, 151). Tn these studies the findings revealed that there

* Also may include mortality data in this presentation.

17
Angina Myocardial Fatat Sudden

 

 

 

 

     

 

 

 

 

 

 

 

 

 

  

 

Pectoris Infarction CHD Death
2.50 —
2.00 —
1.63

¢ 1.50—
=
=
2
3
2
2
5
=

1.00 —

0.50 —

OBS.
EXP.
0.00 HE iE
Non- Heavy Non- Heavy Non- Heavy Non- Heavy
Smoker Smoker Smoker Smoker Smoker Smoker Smoker Smoker
OBS. = number observed EXP. = number expected Heavy smoking indicates more than 1 pack per day

Figure 1—Morbidity ratios for xpecified manifestations of coronary heart
disease, among men aged 30-59 years at entry into Framingham Heart
Study, classified by smoking habit: 12 years’ experience.

Source: Kannel, et al. (70).

were relatively more smokers among the groups with coronary heart
disease, than among the comparison, or control groups.

In a retrospective study of myocardial infarction patients in Japan,
Hyams, et al. (67) reported similar findings, particularly among the
men under age 50, Differences measured by an exposure index com-
bining intensity and duration of smoking showed the same trend,
though the data were not statistically significant.

Dorken (30, 3/) reported on two retrospective studies in Hamburg,
Germany : one, a study of female patients; the other, a study of male
patients. He concluded that there is a strong association between
smoking and myocardial infarction in both males and females under
the age of 45.

In Dublin, Mulcahy, et. al. (106, 108, 109) studied groups of male
and female coronary heart disease patients under age 60. He found that
& much greater portion of the patients, in comparison with a sample
of the general population, smoked cigarettes, Also, the intensity
(amount multiplied by duration) of smoking was as much as 214
times greater among the male patients and 3 times greater among the

18
female coronary heart disease patients as contrasted with the males and
females in the general population.

In a study of 675 aviators, smoking histories taken in 1963 did not
show a positive association in the prevalence of coronary heart disease
with either amount, duration, or intensity of smoking. These findings
are based on 38 cases (5.7 percent) of coronary heart disease of all
forms among a very select: population and are therefore subject to
large sampling variations (96). Moreover, since smokers may have an
excessive mortality during an acute myocardial infarction, as men-
tioned before, prevalence rates are not as good a measure of the asso-
ciation between smoking and coronary heart disease as are incidence
rates.

Epstein (39), although finding no prevalence differences between
smokers and nonsmokers in his Tecumseh Study, found an increased
incidence in cigarette smokers of both fatal and nonfatal coronary
heart disease.

In a short prospective study of 14,000 Norwegian men (12,000 with
smoking histories), Natvig (113) did find an increased risk of inci-
dence of first myocardial infarction or angina pectoris among those
men 50-59 years of age who smoked.

Since the 1967 Report, the continuing prospective epidemiologic
studies have somewhat clarified the differential relationship between
smoking and each of the manifestation categories of coronary heart
disease: angina, nonfatal myocardial infarction, fatal myocardial
infarction and sudden death.

Data from the Framingham Heart Study (69) revealed that “heavy”
cigarette smoking, more than 20 cigarettes per day, is positively asso-
ciated with uncomplicated angina in males but not in females
(figure 2).

Similar findings were reported by Weinblatt (155) in a study of
male subjects in the Health Insurance Plan with the associations more
pronounced among those men who smoked two or more packages of
cigarettes per day. As can be seen, in table 2, the arithmetic differ-
ences in rates between smokers and nonsmokers are greater for myo-
cardial infarction than for angina; however, the risk ratios are
similar.

In a retrospective study, Heyden-Stucki et al. (67) found no asso-
ciation of smoking with angina or other chest complaints.

The inconsistencies in data on the association between smoking and
the development of angina may be due in part to differences in
methods used to diagnose and classify angina and to record smoking
habits in these epidemiologic studies. Further standardization in this
area may help to determine more accurately the relationship of smok-
ing to angina.

19
2.00 — Men Women

 

 

 

  

 

 

 

 

 

 

 

 

|

1.61

150 — I

|

I

I

2 |

= |
Zz

3 1.00— {

5 |
So

= |

|

I

|

0.50 — (

|

I

|

Oss. !

EXP. } {No cases)
0.00 1 | !
Non- 1-20 >20 Non- 1-20 >20
Smoker Cigarette Smokers Smoker Cigarette Smokers

OBS. = number observed
EXP. = number expected

Ficure 2—Angina pectoris morbidity ratios among persons aged 30-59 years at
entry into Framingham Heart Study, classified by sex and number of cigarettes
smoked: 12 years’ experience.

Source: Kannel, et al. (69).

TABLE 2.—Age-adjusted incidence rates per 1,000 males aged 35-64,
and morbidity ratios, for specified manifestations of coronary heart
disease, by smoking category: Health Insurance Plan Study

{3 year observation data]

 

Myocardial infarction Angina

 

Smoking category !
Incidence | Morbidity | Incidence Morbidity

 

rate ratio rate ratio
Current nonsmokers_._.-_____.________. 3. 27 1.0 1. 37 1.0
Current cigarette smokers.__....________ 7.01 2.1 2. 62 1.9
Less than 2 packs._..___________. _- 5. 05 1.5 2. 08 1.5
2 or more packs______________.____ 20. 80 | 6. 4 6. 64 4,8

 

 

 

Source: Weinblatt, E. (756).

20
In the Western Collaborative Study, Rosenman et al. reported
higher rates of silent myocardial infarctions in younger men, and
higher rates of recurrent myocardial infaretions at all ages among
those who smoked more than 25 cigarettes per day (123, 124).

Friedemann, et al. (44) reported reinfarctions occurred more fre-
quently among smokers than nonsmokers.

Dorken (29) found in a series of 330 men of all ages, in Hamburg,
who survived at least 3 and up to 6 years after their first myocardial
infarction, that 172 (52 percent) had stopped smoking completely
after the first infarction. In contrast, of 85 subjects who had died from
a second myocardial infarction or sudden coronary death after leaving
the hospital, only 28 (32.9 percent) had given up smoking completely
(P<0.001).

Re.ationsuips oF Cicsrerre Smoxtxne to Oruer Risk FAacrors

The ongoing prospective and other epidemiologic studies have
yielded findings which permit analysis of the interrelationships among
cigarette smoking and other factors considered to increase the risk
of coronary heart disease.

Age

Generally, the findings show that the incidence rate of coronary
heart disease increases with age, both among smokers and nonsmokers.
The morbidity ratio of coronary heart disease in smokers versus
nonsmokers decreases with age though the absolute number of excess
deaths among smokers increases with age.

High Blood Pressure

Recent reports on the relationship between smoking and blood
pressure appear to support the findings in the 1967 report:

Although the inhalation of cigarette smoke is frequently accom-
panied by acute transit elevations in blood pressure, habitual smokers
tend to have lower blood pressures than do nonsmokers. But, given the
presence of high blood pressure in an individual, smoking acts as an
additional risk factor for the development of coronary heart disease.

Heyden-Stuckiet al. (67) report that among 500 workers in Switzer-
land, smokers, particularly heavy smokers, have lower blood pressure

’ »P 3 y ’ p

as a group than do nonsmokers. Smokers also were found to have
normal or subnormal weights in contrast to nonsmokers who had a
greater mean weight; thus, confounding the relationship between
smoking and blood pressure level. Tibblin (744) in a cohort study of
Scandinavian men born in 1913, found a lower mean blood pressure
among smokers than among nonsmokers. As the population was clas-
sified according to levels of blood pressure, a step-wise decrease in the
prevalence of smoking was noted as the level of blood pressure in-

21
TaBLeE 3.—Afean age and mean systolic and diastolic blood pressure,
by smoking category: Los Angeles Heart Study, 1962

 

| Blood pressure
| (mm. of Hg.)
Current cigarette smoking status

 

 

 

 

 

Number of. Years of | Systolic Diastolie
subjects age
Smokers._.--.--2 22 eee | 407 54, 133.6 82. 5
Nonsmokers...._....--..----.--------- | 728 57 | 137.0 83.9
|
{

 

 

Source: Clark, V. A. (28).

creased. A similar trend for both systolic and diastolic pressures was
also reported by Clark, et al. (23) as shown in table 3.

In the study of 675 aviators (96) smoking intensity, although not
found to be associated significantly with systolic or diastolic blood
pressures, was positively associated with pulse pressure. Reid, et al.
(122) in a comparative study of workers in Great Britain and the
United States noted lower diastolic blood pressures among smokers
than among nonsmokers in both groups; adjustment for weight
variations reduced this difference appreciably.

Mulcahy (707), in a retrospective study of 100 women coronary heart
disease patients under 60 years of age, reported that 50 to 60 percent
had diastolic hypertension (>90 mm. Hg.). Hypertension and ciga-
rette smoking, together or separately, were present in over 80 percent
of these patients.

In the major prospective studies, when both smoking and hyper-
tension were present, an interactive increase in the risk of developing
coronary heart disease was noted. When to these two risk factors
elevated cholesterol levels were added, the risk of developing coronary
heart disease was further increased (figures 38 and 4).

High Serum Cholesterol and Related Diet

Certain of the retrospective and cross-sectional studies (62, 157)
have, in general, demonstrated higher cholesterol levels in smokers
than in nonsmokers. Pincherle, et al. (7/9) and Lane, et al. (96) report
smmilar findings. A study by Heyden-Stucki (67) of 500 Swiss workers
found a similar trend but the differences between smokers and non-
smokers with respect to cholesterol levels and other lipids were not
statistically significant.

A recent report (36) describes some of the variability of interrela-
tionships among smoking, blood pressure and cholesterol levels in
different population groups throughout the world. It concludes that
though nonsmokers tend to be heavier and have higher blood pressure
levels than cigarette smokers, heavy smokers tend to be in the top

22
150-——

 

 

 

 

        

 

 

 

 

 

 

 

 

 

143
125——
c
a
—& 100—
8 8?
a 7—
2
3
€
®
2
é 50—
35
25
o— Tree
11
D Ys ® IE 4 bey bk. .
All None Over- Any 1) Smoking W.C.H. W.C.H. W.C.H.S. W.C.H.S. W.C.H.S. W.C.HS.
positive weight W.C.H. only any 2 any 2 any 2 any 3 any 3 all
only only only only or all only only only or 4
3 only all 4
CHD 46 1 GQ 2 8 4 6 12 V7 23 6
N 1,329 94 161 227 260 159 204 484 222 264 42

Relationship between status with respect to four coronary risk factors (hyper-
cholesterolemia, hypertension, overweight, and cigarette smoking) as evaluated
on original examination and incidence ‘ot clinical coronary heart disease in men
originally age 40-59, free of definite CHD, and followed subsequently without
systematic intervention, Peoples Gas Light and Coke Company study, 1958-1962,
W is overweight, ie, a ratio of observed weight to desirable weight of 1.15 or
greater; C is hypercholesterolemia, ie, serum cholesterol level of 250 mg/100 ml
or greater; H is hypertension, ie, a diastolic blood pressure of 90 mm. Hg or
greater; S is smoking of ten or more cigarettes per day.!

Ficure 3—Incicence of coronary heart disease among men aged 40-59 years at
entry into Peoples Gas Light and Coke Company Study, classified as to pres-
ence of specified rixk factors: 1958-1962.

Source: Stamler, et al. (138).

deciles for blood pressure and relative weight. Cholesterol-smoking
relationships described in these studies do not show a consistent
pattern.

Tn a controlled dietary intervention study of postinfarction patients
Leren (97) found that smoking habits did not influence the serum
cholesterol level or the coronary heart disease relapse rate in the control
group. Among the study group of dieters there was a suggestion,
though not statistically significant at the 0.05 level, that smokers had
a higher coronary heart disease relapse rate than nonsmokers.
Physical. Inactivity

The independent and combined effects of cigarette smoking and
physical activity, as described in the 1967 report, continue to be
demonstrated as more data are accumulated. The apparent protective
effect of physical activity appears to be more pronounced with regard
to myocardial infarction than angina [table 4, (755) ]. Differences
in methods of assessment of history of physical activity In case versus

315-131 O—68——3 23
6.00 ——

5.35

5.00 —

4.00 ——

3.00 —

Morbidity ratio

2.00 ——

 

   

 

0.00

 

 

Any one Any two Any three

Number of abnormalities

OBS. = number observed
EXP. = number expected

Ficcure 4—Myocardial infarction morbidity ratios among men aged 30~59 years
at entry into Framingham Heart Study, classified according to presence of
selected risk factors: 12 years experience (Risk factors are: cholesterol level
over 250 mg/100 ml., systolic blood pressure over 160 mm. Hg., smoking over
1 pack of cigarettes per day).

Source: Kannel, et al. (70).

control groups may account for some differences in the incidence
rates noted.

Blackburn, et al. (70) found no relationship of smoking to the prev-
alence of postexercise ECG changes in a study of 10,260 men age 40
to 59 years. However, there were only 519 (5.1 percent) subjects with a
“positive” ECG response.

Sociological. Psychological and Personality Variables

Two studies (45. 64) demonstrated an inverse relationship between
the frequency of coronary heart disease and the educational level of
the subjects. In the Bell Telephone System (64), those men without
a college education had higher coronary heart disease rates than those
with a college education. Also, those not attending college tended to
smoke more.

In a study of factors related to coronary heart. disease among Cleve-
land attorneys (45), the quality of the law schools attended by the sub-

24
Tapie 4.—Annnal age-adjusted incidence rates of specified manifesta-
tions of coronary heart disease per 1,000 males aged 35-64 and cor-
responding morbidity ratios, by smoking habits and physical activity
class: Health Insurance Plan Study

{3 year observation data}

! Myocardial infarction Angina

 

 

 

 

 

 

 

Smoking status and physical activity class
Incidence Morbility Incidenee Morbidity

 

rate ratio rate ratio

All current nonsmokers... -_------------- / 3,27 1.0 1.37 1.0
Not cigarette smokers:

Least active... .----------------- 6. 33 1.9 2.14 1.6

Intermediate. .._.-_--------------- 3. 07 0.9 1. 67 1.2

Most active._-------------- oe eee 3. 01 0.9 1. 32 .0
All current cigarette smokers:

Least active._._-...--------------- 10. 89 3.3 2.31 1.7

Intermediate.._..----------------- 5. SO LS 2. 83 2.1

Most active....-.----------------- 5.77 18 2.74 2.0
Less than 2 packs:

Least active......----------------- - 7.61 2.3 2.05. 1.5

Intermediate.....__--------------- * 4.71 1.4 2.37. 17

Most active....._----------------- ; 3. 85 1, 2 1.95 4
2 or more packs: ' |

Least active.......---------------- | 39.09 12.0 4, 97 3.6

Intermediate__._.----------------- 11, 27 3.5 5. 09 3.7

Most active......----------------- | 24, 09 7 12, 20 8.9

 

So ree: Weinblatt, E. (168).

ject were ranked independently by a law school professor. Lawyers
attending schools in the “highest law school quality group” had
lower rates of coronary heart disease than those attending schools in
the “lower law school quality group.” Also, those in the latter group
had started smoking at an earlier age. Since additiona] differences
were noted for other risk factors, smoking alone may not be responsible
for the total differences in these rates. In both studies, it was hypothe-
sized that with respect to susceptibility to development of coronary
heart disease, behavior patterns and attitudes established prior to
professional training and prior to stresses resulting from job mobility
and job tension, were more significant than the later stresses which
resulted from their present jobs.

Recent data from the Western Collaborative Group Study (125)
appear to show that among men 39—49 years of age, cigarette smoking
was associated with several coronary heart disease risk factors (table
5), Though these findings may be statistically significant, the differ-
ences between smokers and nonsmokers were small.

25