13. OTHER FORMS OF TOBACCO USE.

 

Center for Disease Control
CONTENTS

 

 

 

 

 

Introduction .........cccccecceneceeeeeeeeeeee re eeeeeeenee nen ee en ece sree 7

Pipes and Cigars.........c.:-sesssesseereeseereeerseesereeseenennesses 7

Prevalence of Pipe, Cigar, and Cigarette Usage ........ 8
The Definition and Processing of Cigars, Cigarettes,

and Pipe Tobaccos .........-.ssescerersereeerersseenseeseeeey 10

Cigarettes. ..........cccceeeeteeeeeeeeeeeeeeeeeetenetrenenenes 10

Cigars.........cccceeeeeeeeeeeneeeeseeeeeseenaaannreneengenegs 10

Pipe Tobaccos .........-.0ccseseesseeeererereeeseeeeeeeenees 11

Conclusion .........0ceccecececee eee c ee eneeeceeeeeteenenecees 11

Chemical Analysis of Cigar Smoke.........-....0--1+see0+ 11

Mortallity..........::cccccceessereeseneeeeeeneaneeeeseeee nee eenee es 13

Overall Mortality ..........0.:eecseeeeeeeeereeeeeeneenenes 13

Mortality and Dose-Response Relationships ....... 14

Amount Smoked...........:.ccsseecseeeeeeeeeeneeeneen oes 14

Imhalation.............0ccceceeeceecee eens ea erenonseetesaenes 15

Specific Causes of Mortality...........:::cerceceeeeesteseeees 20

CANCEL ....ccec ec eceecececnc ee eeeeeeeeeeeenengeensneeeeeeneg ees 20

Cancer of the Lip..........cccsceeeeeeeseeeereeeen ones 21

Oral Cancer .........c.ceeeceeec es eeteaeencneeeweeesenees 21

Cancer of the Larynx..........--:eseeeeereeeeeeeen ee 2

Cancer of the EsophaguS........--.--ssssereeeereres 24

Lung Cancer .........:.cccseeceeeereeeeeeneerneeceaeenes 26

Tumorigenic Activity ...........::.seeeeeeee secrete ee 30

Cardiovascular Diseases ...........::eccseeeeereneeeeenee 32

Chronic Obstructive Pulmonary Disease............ 34

Gastrointestinal Disorders...............------seseeeeees 38

Snuff and Chewing Tobacco .............ccceeecseeeeeeerenteceees 38

Prevalence of Snuff Use and Tobacco Chewing........ 39

Benign Oral Lesions and Oral Cancer...........-.-++++++ 39

Conclusions. ......2.0csecseececcec eee eeeeescesesseeeeeeneeeesnensemene sees 41

References .......ccccccceceesccnceeeeeeenesteceaenesenesuec ene eneeennees 43

13—3
LIST OF TABLES

Table 1.—Percent distribution of U.S. male smokers aged
21 and older by type of tobacco used for the years 1964,
1966, 1970, and 1975.22... cccec cee ceecee ee ecneeneeee renee ees 9

 

 

Table 2.—Percent distribution of U.S. male smokers by
type of tobacco used and age, for 1970. Prevalence of
snuff use and tobacco chewing in the United States..... 9

 

Table 3.—A comparison of several chemical compounds
found in the mainstream smoke of cigars, pipes, and
CIZATELLES .... oe cece cee eens ee eee etre eee eee e see een eee nese nese sees 12

 

Table 4.—Mortality ratios for total deaths by type of
smoking (males only) ..........::.:ececceereceeecneseeeneeesnenseas 14

 

Table 5.—Mortality ratios for total deaths of cigar and
pipe smokers by amount smoked...............-:eseseeeeeevees 15

 

Table 6.—Mortality ratios for total deaths of cigar and
pipe smokers by amount smoked.................-:ssseeeeeeee 16

 

Table 7._Mortality ratios for total deaths of cigar and
pipe smokers by age and amount smoked .................- 17

 

Table 8.—Mortality ratios for total deaths of cigar and
pipe smokers by amount smoked...............::.:seeseeeeeees 17

 

Table 9.—The extent of inhaling pipes, cigars, and
cigarettes by British males aged 16 and over in 1968
ANG 1971... cee cece cece eee e eee e ence ee eet ee eee ee ene ne ene eeg ee enes 19

 

Table 10.—Mortality ratios for total cancer deaths in cigar
and pipe smokers. A summary of prospective
epidemiological studies .............-::ceseeeeee sees eeeeeeneeeneas 20

 

Table 11.—Relative risk of lip cancer for men, comparing
cigar, pipe, and cigarette smokers with nonsmokers. A
summary of retrospective studies ...............::2seseeeeeeres 22

13—4
 

Table 12.—Mortality ratios for oral cancer in cigar and
pipe smokers. A summary of prospective epidemiological
StUGIOS......2cccccececececececec esse eeeeeneneecen ee teeee nen eee eerseeees 23

 

Table 13.—Mortality ratios for cancer of the esophagus in
cigar and pipe smokers. A summary of prospective
epidemiological studies ............:-:cccssesetessrrreeeettrttsees 25

 

Table 14.—Relative risk of cancer of the esophagus for
men, comparing cigar, pipe, and cigarette smokers with
nonsmokers. A summary of retrospective studies......... 26

 

Table 15.—Mortality ratios for lung cancer deaths in male
cigar and pipe smokers. A summary of prospective
StUICS.......0.ccceceeceeeceececeereeeneeeenen ene neeeeeeene seers eee nnees 27

 

Table 16.—Lung cancer death rates for cigar and pipe
smokers by amount smoked ............::eeseeeeeerseeeeeeneeees 27

 

Table 17.—Lung cancer mortality ratios for cigar and pipe
smokers by amount smoked ...........::-e1seeesereesereeerteees 28

 

Table 18.—Relative risk of lung cancer for men, comparing
cigar, pipe, and cigarette smokers with nonsmokers. A
summary of retrospective studies ........--..:::+s:-eerrererees 29

 

Table 19.—Mortality ratios for cardiovascular deaths in
male cigar and pipe smokers. A summary of prospective
epidemiological studies ...........:s:sseeeeeeeeereeeeeeetresenetees 33

 

Table 20.—Mortality ratios for chronic obstructive
pulmonary deaths in male cigar and pipe smokers. A
summary of prospective epidemiological studies........... 35

 

Table 21.—Prevalence of respiratory symptoms and illness
by type of smoking ............::::::seeeeereeteeeeeeeterer ee eeenes 36

 

Table 22.—Pulmonary function values for cigar and pipe
smokers as compared to nonsmokefS............--112s+eree00 38

13—5
Introduction

This review of the health effects of tobacco use other than cigarette
smoking includes a revision of the chapter on pipes and cigars from the
1973 Health Consequences of Smoking and information on tobacco
chewing and snuff dipping. Because these forms of tobacco are used
mainly by men in the United States, most studies report data based
only on male populations. This information can be applied to the small
numbers of women who use other forms of tobacco only with caution
because there is some difference in the impact of cigarette smoking on
men and on women.

Pipes and Cigars

Prospective epidemiologic studies show that individuals who smoke
only pipes and cigars have overall mortality rates slightly higher than
nonsmokers, but lower than cigarette smokers. Pipe and cigar smokers
have only slightly elevated cause-specific mortality rates for coronary
heart disease, lung cancer, and chronic obstructive pulmonary disease
when compared to nonsmokers, but their mortality rates for oral cavity
cancers often equal or exceed those of cigarette smokers. Examination
of the combined use of cigarettes and pipes or cigars is complex and
may lead to confusion in two areas.

First, overall mortality rates of those who smoke pipes, cigars, or
both in combination with cigarettes appear to be intermediate between
the high mortality rates of cigarette smokers and the lower rates of
those who smoke only pipes or cigars. This should not be taken to
suggest that smoking pipes or cigars in combination with cigarettes
diminishes the harmful effects of cigarette smoking. Analysis of
mortality associated with smoking combinations of cigarettes, pipes,
and cigars should be standardized for the level of consumption of each
of the products smoked in terms of the amount and duration of
smoking and the depth and degree of inhalation. For example, cigar
smokers who also smoke a pack of cigarettes a day might be expected
to have mortality rates somewhat higher than those who smoke only a
pack of cigarettes a day, assuming that both groups smoke cigarettes
in the same way. Mixed smokers who inhale pipe or cigar smoke in a
manner similar to the way they smoke cigarettes might be expected to
have higher mortality rates than mixed smokers who do not inhale
cigars and pipes and resist inhaling cigarettes. Unfortunately, little
published material on mixed cigarette, pipe, and cigar smoking
contains these types of analyses or controls.

Second, a paradox seems to exist between reduced mortality rates
for ex-smokers of cigarettes, compared to continued smokers, and
increased mortality rates for ex-smokers of pipes and cigars. Ex-
cigarette smokers experience a relative decline in overall and certain
specific causes of mortality following cessation. This decline is

13—7
important but indirect evidence that cigarette smoking is a major
cause of elevated mortality rates experienced by current cigarette
smokers.

In contrast to this finding, several prospective epidemiological
investigations, Hammond and Horn (52), Best (171), Kahn (69), and
Hammond (50), have reported higher death rates for ex-pipe and ex-
cigar smokers than for current pipe and cigar smokers. This
phenomenon was analyzed by Hammond and Garfinkel (51). They
found that the development of ill health often results in a cigarette
smoker giving up the habit, reducing his daily tobacco consumption,
switching to pipes or cigars, or choosing a cigarette low in tar and
nicotine. In many instances, a smoking-related disease is the cause of ill
health. Thus, the group of ex-smokers includes people who are already
ill from smoking-related diseases and who therefore have higher
overall and specific mortality rates. With the passage of time after
cessation of cigarette smoking, a relative decrease in mortality is
observed due to decreased mortality rates in those who quit smoking
for reasons other than ill health and in the dwindling number of il] ex-
smokers.

The beneficial effects of cessation tend to be obscured by the high
mortality rates of those who quit smoking for reasons of illness. A
similar principle operates for ex-pipe and ex-cigar smokers; because of
the lower initial risk of smoking these forms and the smaller margin of
benefit following cessation, the effect produced by the ill ex-smokers
creates a larger and more persistent impact on the mortality rates than
is seen in cigarette smoking. For these reasons, a detailed analysis of
mortality among ex-pipe and ex-cigar smokers will not be undertaken
in this review.

For specific causes of death, the tables below summarize the
mortality and relative risk ratios reported in major prospective and
retrospective studies of pipe and cigar smokers. The smoking
categories used include: cigar only, pipe only, total pipe and cigar,
cigarette only, and mixed. Mortality and relative risk ratios are
calculated relative to nonsmokers.

Prevalence of Pipe, Cigar, and Cigarette Usage

Prevalence of pipe, cigar, and cigarette smoking in the United States
was estimated by the National Clearinghouse for Smoking and Health
from population surveys conducted in 1964, 1966, 1970, and 1975 (90, 91,
92). In each survey, over 2,500 interviews were conducted on a national
probability sample stratified by type of population and geographic
area. The use of these products among adults aged 21 and older,
summarized in Table 1, reflects the continued decline in the percentage
of the population using tobacco products. Table 2 shows the use of
different tobacco products by age group.

18-8
TABLE 1.—Percent distribution of U.S. male smokers aged 21
and older by type of tobacco used for the years 1964,
1966, 1970, and 1975

 

Forms used 1964 1966 1970 1975
(percent) (percent) (percent) (percent)
Total pipe 18.7 19.2 17.9 12.4
Total cigar 29.9 26.7 212 19.9
Total cigarette 52.9 52.4 42.3 39.3

 

SOURCE: National Clearinghouse for Smoking and Health (90,91,92).

TABLE 2.—Percent distribution of U.S. male smokers by type of
tobacco used and age, for 1970

Age groups

 

 

 

 

 

 

 

Forms used
21 to 34 35 to 44 45 to 54 55 to 64 65 to T5+
1. Cigar only........-.....-++ 3.7 65 47 6.7 93
2. Pipe only..........-..06--- 4.3 3.5 3.0 3.2 3.6
3. Pipe and cigar............ 38 33 52 44 69
4. Cigarette only..........-. 28.8 29.0 27.1 24.3 13.6
5. Cigarette and cigar...... 68 104 5.5 5.2 42
6. Cigarette and pipe....... 6.6 44 5.6 4.0 3.8
7. Cigarette, pipe, and 58 48 5.0 4.0 14
Cigar... eee cece eters
8. Nonsmoker............--.- 40.2 38.1 43.9 48.2 57.2
Total...... 100.0 100.0 100.0 100.0 100.0
Number of persons in 1,009 528 523 405 388
sample............:ecceeeeeeee
Total pipe users............-.- 20.5 16.0 18.8 15.6 15.7
Total cigar users.............. 20.1 25.0 20.4 20.3 21.8
Total cigarette users......... 48.1 48.6 433 37.5 23.0

 

SOURCE: National Clearinghouse for Smoking and Health (91).

13—9
TABLE 2.—continued. Prevalence of snuff use and tobacco
chewing in the United States

 

 

 

1970 1975
Male Female Male Female
Snuff 29 14 25 13
Chewing 5.6 0.6 49 0.6

 

SOURCE: National Clearinghouse for Smoking and Health (92,92)

The Definition and Processing of Cigars, Cigarettes, and Pipe
Tobaccos

Cigarettes

The U.S. Government has defined tobacco products for tax purposes.
Cigarettes are defined as “(1) Any roll of tobacco wrapped in paper or
in any substance not containing tobacco, and (2) any roll of tobacco
wrapped in any substance containing tobacco which, because of its
appearance, the type of tobacco used in the filler, or its packaging and
labeling, is likely to be offered to, or purchased by, consumers as a
cigarette described in subparagraph (1).” Cigarettes are further
classified by size, but virtually all cigarettes sold in the United States
are “small cigarettes” which by definition weigh “not more than 3
pounds per thousand,” which is not more than 1.3861 grams per
cigarette (44, 130, 141).

Cigars

Cigars have been defined for tax purposes as: “Any roll of tobacco
wrapped in leaf tobacco or in any substance containing tobacco (other
than any roll of tobacco which is a cigarette within the meaning of
subparagraph (2) of the definition for cigarette)” (141). In order to
clarify the meaning of “substance containing tobacco,” the Treasury
Department has stated that, “The wrapper must (1) contain a
significant proportion of natural tobacco; (2) be within the range of
colors normally found in natural leaf tobacco; (3) have some of the
other characteristics of the tobaccos from which produced; e.g.,
nicotine content, pH, taste, and aroma; and (4) not be so changed in the
reconstitution process that it loses all the tobacco characteristics” (131).
Further, “To be a cigar, the filler must be substantially of tobaccos
unlike those in ordinary cigarettes and must not have any added
flavoring which would cause the product to have the taste or aroma
generally attributed to cigarettes. The fact that a product does not
resemble a cigarette (such as many large cigars do not) and has a
distinctive cigar taste and aroma is of considerable significance in
making this determination” (45, 131).

13—10
Pipe Tobaccos

The definition of pipe tobacco used by the U.S. Government was
repealed in 1966, and there is no Federal tax on pipe tobaccos. The
most popular pipe tobaccos are made of Burley; however, many pipe
tobaccos are blends of different types of tobacco. A few contain a
significant proportion of midrib parts that are crushed between rollers.
“Saucing” material, or casings containing licorice, sweetening agents,
sugars, and other flavoring materials are added to improve the flavor,
aroma, and smoke taste. These additives modify the characteristics of

smoke components (141).

Conclusion

Because of the curing and processing methods used in the production
of cigar and pipe tobaccos, there are significant physical and chemical
differences between pipe and cigar tobaccos and those used in
cigarettes. The extent to which these changes may alter the health
consequences of smoking pipes and cigars can best be estimated by an
analysis of the potentially harmful chemical constituents found in the
smoke of these tobaccos, the tumorigenic activity of smoke condensates
in experimental animals, and a review of the epidemiological data
which have accumulated on the health effects of pipe and cigar
smoking.

Chemical Analysis of Cigar Smoke

Only a few studies have been conducted that compare the chemical
constituents of cigar smoke with those found in cigarette smoke.
Hoffmann, et al. (60) compared the yields of several chemical
components in the smoke from a plain 85 mm cigarette, two types of
cigars, and a pipe. The particulate matter, nicotine, benzo(a)pyrene,
and phenols were determined quantitatively in the smoke of these
tobacco products. One cigar tested was a 135-mm-long, 7.8-g, U.S.-
made cigar. The other was a handmade Havana cigar 147 mm long
weighing 8.6 g. The relative content of nicotine in the particulate
matter produced by the cigars was similar to that of the cigarette tars.
The benzo(a)pyrene and phenol concentrations in the cigar condensate
was two to three times greater than in cigarette tar. Kuhn (78)
compared the alkaloid and phenol content in condensates from an 80-
mm bright-blend cigarette sold commercially in Austria with that
obtained from 103-mm cigars. These were tested with and without the
use of a cellulose acetate filter. The concentrations of total alkaloids
and phenol in the cigar smoke condensate were essentially the same as
in the cigarette condensate, but pyridine values were about 2 1/2 times
higher in the cigar condensate.

Campbell and Lindsey (27) measured the polycyclic hydrocarbon
levels in the smoke of a small popular-type cigar 8.8 cm long, weighing

13—11
TABLE 3.—A comparison of several chemical compounds found
in the mainstream smoke of cigars, pipes, and

 

 

 

cigarettes
Compound Micrograms per 100 g. of tobacco consumed
Cigars Pipes! Cigarettes
Acenaphthylene ...........-.-..2:cce seen eens 1.6 29.1 5.0
Anthracene ...............0...:cesee ese ee eee tees 119 110.0 109
PYTONE ooo cece e cece eee ee eee eeee 17.6 75.5 125
B,4-Denzpyrene 2.0.0... cece ce cee ee eee nee eee 3.4 8.5 9

 

{With a light pipe tobacco.
SOURCE: Campbell, J.M., (22).

1.9 g. Significant quantities of anthracene, pyrene, fluoranthene, and
benzo(a)pyrene were detected in the unsmoked cigar tobacco, in
concentrations much greater than those found in Virginia cigarettes
but of the same order as those found in some pipe tobaccos. The
smoking process contributed considerably to the hydrocarbon content
of the smoke. Table 3 compares the concentrations in the mainstream
smoke of cigarettes, cigars, and pipes of four hydrocarbons frequently
found in condensates. The authors reported that the mainstream
smoke from a popular brand of small cigar contained the polycyclic
aromatic hydrocarbons: acenaphthylene, phenanthrene, anthracene,
pyrene, fluoranthene, and benzo(a)pyrene. The concentrations of these
hydrocarbons in the mainstream smoke were greater than those found
in Virginia cigarette smoke.

Osman, et al. (94) analyzed the volatile phenol content of cigar
smoke collected from a 7-g American-made cigar with domestic filler.
After quantitative analysis of phenol, cresols, xylenols, and meta and
para ethyl phenol, the authors concluded that the levels of these
compounds were generally similar to those reported for cigarette
smoke. Osman and Barson (93) also analyzed cigar smoke for benzene,
toluene, ethyl benzene, m-, p-, and o-xylene, m- and p-ethyltoluene,
1,2,4-trimethylbenzene, and dipentene and generally found levels
within the range of those previously reported for cigarette conden-
sates.

Brunnemann and Hoffmann (28) found that the mainstream smoke
from regular and small cigars contains more carbon monoxide per puff
and per gram of tobacco burned than filtered or unfiltered cigarettes.
This greater production of carbon monoxide was confirmed by Harke
(54).

In summary, available evidence suggests that cigar smoke contains
many of the same chemical constituents, including nicotine and other

13—12
alkaloids, phenols, and polycyclic aromatic hydrocarbons as are found
in cigarette smoke. Most of these compounds are found in concentra-
tions which equal or exceed levels found in cigarette tar.

Mortality
Overall Mortality

Several large prospective studies have examined the health conse-
quences of various forms of smoking and the results of these
investigations have been reviewed in previous reports of the Surgeon
General in which the major emphasis was on cigarette smoking and its
effect on overall and specific mortality and morbidity. The following
pages present a current review of the health consequences of smoking
pipes and cigars. Data from the prospective investigations of Dunn, et
al. (40), Buell, et al. (20), Hirayama (58), and Weir and Dunn (134) are
not cited because in these studies a separate category for pipe and
cigar smokers was not established. .

The smoking habits and mortality experience of 187,783 white men
between the ages of 50 and 69, followed for 44 months, were reported
by Hammond and Horn (53). The overall mortality rates of men who
smoked pipes or cigars were slightly higher than the rates of men who
never smoked. The overall mortality rate of cigar smokers was slightly
higher than that of pipe smokers. ©

Doll and associates (34, 35, 38) followed the mortality of 41,000
British physicians for 20 years and reported an overall mortality ratio
of 1.09 for men who smoked only pipes and cigars and who had never
been cigarette smokers. When compared to nonsmokers, the mortality
ratio for mixed smokers of cigarette, pipe, and cigar was 1.20. This
represents a slight increase in the ratios since the report of the 10-year
follow-up. Best (11), in a study of 78,000 Canadian veterans, reported
overall mortality rates of pipe and cigar smokers slightly above those
of nonsmokers. Rogot (104), in an update of Kahn’s study of over
298,000 U.S. veterans, found that pipe smokers had only a minimally
increased risk of death when compared to nonsmokers, but the risk for
cigar smokers was substantially higher. The risk for combined pipe and
‘cigar smoking was between the risks of either one separately.
Hammond (50) examined the smoking habits of and mortality rates
experienced by 440,559 men and found that pipe smokers experienced
mortality rates similar to those of men who never smoked regularly,
whereas cigar smokers had death rates somewhat higher than men
who never smoked regularly. Table 4 summarizes some of the results of
those studies.

Thus, data from the major prospective epidemiological studies
demonstrate that the use of pipes and cigars results in a small but
definite increase in overall mortality. Cigar smokers have somewhat
higher death rates than pipe smokers, and mixed smokers who use

13-13
TABLE 4.—Mortality ratios for total deaths by type of smoking
(males only)

 

 

Smoking type
* Author, . . . Mixed
reference Non- Cigar Pipe Cigar Cigarette Cigarette (cigarette Cigarette
and and and
smoker only only . and only

pipe cigar pipe other)

 

Hammond and

Horn! (52)............. 1.00 1.22 1,12 1.10 1.36 1.50 148 1.68
Doll and

Peto (88) ....cccccecee 400000... eee 0 eee 120 1.64
Best (12)..........0:.0005 1.00 1.06 1.05 98 1.22 1.26 113 1.54
Kahn (69)...........0000+ 1.00 1.10 1.07 1.08 tee wee 151 1,84
Hammond? (50) ......... 1.00 125 119 101 tee tee 157 1.86

 

10nly mortality ratios for ages 50 to 69 are presented.
20nly mortality ratios for ages 55 to 64 are presented.

cigarettes in addition to pipes and cigars appear to experience an
intermediate level of mortality that approaches the mortality experi-
ence of cigarette smokers.

Mortality and Dose-Response Relationships

A consistent association exists between overall mortality and the total
dose of smoke a cigarette smoker receives. The methods most
frequently used to measure dosage of tobacco products are: amount
smoked, degree of inhalation, duration of smoking experience, age at
initiation, and the amount of tar in a given tobacco product. For
cigarette smokers, the higher the dose as measured by any of these
parameters, the greater the mortality. The significance of the small
increase in overall mortality that occurs for the entire group of pipe
and cigar smokers can be analyzed by examining the mortality of
subgroups defined by similar measures of dosage as used in the study
of cigarette smokers.

Amount Smoked

Hammond and Horn (52) reported an incr»ase in the overall mortality
of pipe and cigar smokers wi: an in. case in the amount smoked.
Individuals who smoked more '1an four cigars a day or more than ~

pipefuls a day had death ratcs significantly higher than men who
never smoked (P < 0.05 for cigar smokers and P < 0.05 for pipe
smokers) (Table 5). Cigar and pipe users who smoked less than this
amount experienced an overall mortality similar to men who never
smoked. The study of Canadian veterans (11) also contained evidence
of a dose-response in mortality by amount smoked for cigar smokers.
No dose-response relationship was observed among pipe smokers
(Table 6). Kahn (69) reported a consistent increase in overall mortality
with an increase in the amount smoked for both pipe and cigar smoko

13—14
TABLE 5.—Mortality ratios for total deaths of cigar and pipe
smokers by amount smoked

Amount smoked Number of deaths

 

 

Observed Expected Mortality ratio
Nonsmoker..........:0e0ceee cere sense eee ee eens 1,664 1,664 1.00
Cigar only:

Total ....cccccseecerer ee een creer ee ete ee nents 653 598 1.09

1 to 4 Cigars........ce cece ereeee ert ner tenes 410 400 1.08

D> 4 CIGAFS ...o cece eee treet teeters 229 185 1.24
Pipe only

Total ..ccccccececee ee ee eee ec nen en eeees tee er es 609 560 1.09

1 to 10 pipefuls ...........s-ereee eee ete 391 374 1.05

> 10 pipefuls..........-.-.:ceceeeeerreee es 204 172 119

 

SOURCE: Hammond, E.C., Horn, D. (52).

(Table 7). Hammond (50) found no consistent relationship between
overall mortality and the number of cigars or pipefuls smoked (Table
8).

The above evidence suggests that a dose-response relationship may
exist between the number of cigars and pipefuls smoked and overall
mortality. However, because of the high-mortality rate of ex-smokers
of cigars and pipes, it is difficult to interpret the data presented
without including this group with the continuing smokers. Without
data which examine patterns of both daily rate of smoking and
inhalation at various age levels, no firm conclusions can be drawn as to
the nature of this dosage relationship.

Inhalation

Inhalation of tobacco smoke directly exposes the bronchi and the lungs
to smoke and results in the absorption of the soluble constituents of the
gas and particulate phases. Without inhalation, tobacco smoke reaches
mainly the oral cavity and some upper digestive and respiratory tracts
but it does not reach the lungs where further direct effects and
systemic absorption of various chemical compounds can occur.

The condensate of pipe and cigar smoke is generally found to be
alkaline when the pH is measured by suspending a Cambridge filter in
CO--free water. Cigarette condensate is slightly acidic as measured by
this method. Since alkaline smoke is more irritating to the respiratory

13—15
TABLE 6.—Mortality ratios for total deaths of cigar and pipe
smokers by amount smoked

Amount smoked Number of deaths

 

 

Observed Expected Mortality ratio

Nonsmoker _ - 1.00
Cigar only:

Total 0.0.0.0... ccc ce ccc eee eee eee ee tee te enes 90 82.07 1.10

1 to 2 cigars........... cece eee re eee ne eee 64 56.05 114

3 to 10 cigars........cccccceceseeseeeeeees B 19.40 1.19

> 10 Cigars... 0. cece cence ne eees 1 1.59 63
Pipe only

Total... 0... cece cece nsec ce eee nee ee eee eennee 570 566.99 1.00

1 to 10 pipefuls ............. cece eee eee eee 374 370.09 1.01

10 to 20 pipefuls 00.2.2... cece eres 141 140.84 1.00

> 20 pipefuls....... 0... eee tenes 36 35.90 1.00

 

SOURCE: Best, E.W.R. (71).

tract, it has been assumed that the more alkaline smoke of pipes and
cigars was in part responsible for the lower levels of inhalation
reported by pipe and cigar smokers. Brunnemann and Hoffmann (19)
have analyzed the pH of whole, mainstream smoke of cigarettes and
cigars on a puff-by-puff basis using a pH electrode suspended in
mainstream smoke. Smoke from several U.S. brands of cigarettes was
found to be acidic throughout the entire length of the cigarette. Of
interest was the finding that cigar smoke also had an acidic pH for the
first two-thirds of the cigar and became alkaline only in the last 20 to
40 percent of the puffs from the cigar. Epidemiological evidence
indicates that most cigar smokers do not inhale the smoke while most
cigarette smokers do. The fact that smoke from the first half or more
of a cigar is acidic, near the range of pH values commonly found in
cigarette smoke, and becomes alkaline only toward the end of the cigar
might suggest that the pH of the smoke of a tobacco product may not
be the only factor that influences inhalation patterns. Perhaps tar and
nicotine levels as well as the concentration of other irritating chemicals
also affect the degree to which a tobacco smoke will be inhaled.
Nicotine is rapidly absorbed into the blood stream from the lungs
when tobacco smoke is inhaled. The amount of nicotine absorbed from
the lungs is primarily a function of the nicotine concentration in the

13—16
TABLE 7.—Mortality ratios for total deaths of cigar and pipe
smokers by age and amount smoked

Amount smoked Mortality ratio, age

 

 

55 to 64 65 to 74
Nonsmoker.........-.:eceeeeeereereeee nen eeere es 1.00 1.00
Cigar only:

Total ...ccccccceeceec eee eee eeenese een neennnees 1.01 1.08
1 to 4 cigars per day.......-..:-s errr 89 1.00
5 to 8 cigars per day.......-.:-seeeeree 1.14 1.23
‘> 8 cigars per day....-...--.eerrrre 1.65 1.28
Pipe only:
Total .....ccccceecec ee ce eee ee reese ree en net ens 1.08 1,06
1 to 4 pipefuls per day ...--...--.--ss20 1.16 91
5 to 19 pipefuls per day ........------+++++ 1.04 1.10
> 19 pipefuls per day .......-.---+2-se0 1.04 1.18

 

SOURCE: Kahn, H.A. (69).

TABLE 8.—Mortality ratios for total deaths of cigar and pipe
smokers by amount smoked

 

 

Amount smoked Mortality Amount smoked Mortality
ratio ratio
Nonsmoker......-..0000eeeeececeeeeeeeees 1.00 Current pipe smokers:
Current cigar smokers: Total ....c..cccceccnce sence seers ee eseeneee es 1.04
Total ........cecee cece eer e ee ete eee ee ts 1.09 1 to 9 pipefuls per day..........----. 1.08
1 to 4 cigars per day........--.---+ 1.08 > 9 pipefuls per day .....-..---..-++ 92
> 4 cigars per day.......-...sr 1.18

 

SOURCE: Hammond, E.C. (50)

smoke and the depth of inhalation. Some nicotine may also be absorbed
through the mucous membranes of the mouth. This is more likely to
occur under alkaline conditions when nicotine is unprotonated (4, 19,
108). This suggests that cigar smokers may absorb some nicotine
through the oral cavity without inhaling, particularly during the time

13—17
that the smoke from the cigar is alkaline. With the development of
sensitive measures of serum nicotine levels (65), the extent to which
nicotine is absorbed through the membranes of the mouth in pipe and
cigar smokers can be more accurately determined.

Inhalation patterns of smokers were determined in several of the
large prospective and some of the retrospective epidemiological
studies. Inhalation was usually determined by the administration of a
questionnaire that required a subjective evaluation of one’s own
patterns of inhalation. Although the accuracy of these questionnaires
has not been confirmed by an objective measure of inhalation, such as
carboxyhemoglobin or serum nicotine levels, their reliability is
supported by mortality data which demonstrate higher overall and
specific death rates with self-reported increases in the depth of
inhalation.

Doll and Hill ($4) and Hammond (50) presented information on
inhalation patterns of pipe, cigar, and cigarette smokers. Some 80 to 90
percent of cigarette smokers reported inhaling, the majority inhaling
moderately or deeply, whereas more pipe and cigar smokers denied
inhaling at all. For each type of smoking, less inhalation was reported
by older smokers. This change may represent less awareness of
inhalation, differences in smoking habits of successive cohorts of
smokers, or it may reflect the operation of selective factors which
favor survival of noninhalers.

The Tobacco Research Council of the United Kingdom has, since
1957, periodically reported the use of tobacco products by the British.
Recent reports edited by Todd have contained data on the inhalation
pattern of cigar, pipe, and cigarette smokers (126, 127, 128). Table 9
shows that most cigarette smokers inhale a “lot” or “fair amount”
whereas most pipe and cigar smokers do not inhale at all or “just a
little.” Little change is observed in the inhalation patterns of a given
product since 1968.

Carbon monoxide is poorly absorbed by the oral mucosa and,
therefore, carboxyhemoglobin levels represent a good measure of the
degree of inhalation of a given smoker. Several investigators (22, 68,
101) have found that pipe and cigar smokers have lower levels of
carboxyhemoglobin than cigarette smokers and that the levels in pipe
and cigar smokers who have never smoked cigarettes approach the
levels found in nonsmokers.

The overall mortality rates of current pipe smokers who inhaled at
least slightly were reported by Hammond (50) as being somewhat
higher than for men who never smoked regularly. The overall
mortality rates of current cigar smokers who reported inhaling at least
slightly were appreciably higher than for men who never smoked
regularly.

Evidence indicates that cigarette smokers inhale smoke to a greater
degree than smokers of cigars or pipes. Once a smoker has learned to

13—18
TABLE 9.—The extent of inhaling pipes, cigars, and cigarettes
by British males aged 16 and over in 1968 and 1971

 

 

 

 

 

Tobacco product
Amount of inhalation Cigars Pipes Cigarettes

1968 1971 1968 1971 1968 1971
Inhale a lot............:-eere ee eee rere 2B 19 & 8 47 AT
Inhale a fair amount........---.--.++ 16 19 10 8 31 30
Inhale just a little..........--.:--see 27 27 2 26 18 bt)
Do not inhale at all........-...-.-0-- 34 35 59 58 9 8
Total........ecee eee 100 100 100 100 100 100

 

SOURCE: Todd, G.F. (127,128)

inhale cigarettes, however, there appears to be a tendency also to
inhale the smoke of other tobacco products. For cigars, this is evidently
true whether one smokes both cigarettes and cigars or switches from
cigarettes to cigars.

Bross and Tidings (17) examined the inhalation patterns of smokers
of large cigars and cigarettes and those who switched from one tobacco
product to another. Nearly 75 percent of those currently smoking only
cigarettes reported inhaling “almost every puff” and only 7 percent
never inhaled. The opposite was true for persons who had always
smoked only cigars, among whom 4 percent reported inhaling almost
every puff and 89 percent saying they never inhaled. Cigar smokers
who also smoked cigarettes reported intermediate levels of inhalation
between the cigar-only and cigarette-only categories. Inhalation
patterns were similar whether the individual continued to smoke both
products, stopped smoking cigarettes but continued smoking cigars, or
stopped smoking cigarettes and switched to cigars. In all three groups,
about 20 percent reported inhaling “almost every puff.” This suggests
that, once an individual’s inhalation patterns are established on
cigarettes, he may be more likely to inhale cigar smoke if he switches
to cigars or uses both cigars and cigarettes than the cigar smoker who
has not smoked cigarettes.

Todd (128) reported similar data for a sample of smokers in the
United Kingdom. The prevalence of inhaling a “lot” or “fair amount”
of smoke was highest among cigarette smokers who were currently
smoking cigarettes (77 percent) and lowest among current cigar
smokers who had previously smoked only cigars or pipes (18 percent).
Individuals who switched from cigarettes to cigars maintained
somewhat higher levels of cigar smoke inhalation than those cigar
smokers who had never smoked cigarettes (30 percent).

13—19
TABLE 10.—Mortality ratios for total cancer deaths in cigar and
pipe smokers. A summary of prospective
epidemiological studies

Type of smoking

 

Author, reference : 7
Nonsmoker _ Cigar only Pipe only Total pipe Cigarette

 

and cigar only
Hammond and Horn (52).... 1.00 1.34 1.44 Lee 1.97
Best (11)..cccccccscseceeceeeeee 1.00 1.18 1.38 a 2.06
Hammond (50) .......0.0.000+- 1.00 ee bees 121 L16
Kahn (69)..........c:ccceeeee es 1.00 1.22 1.25 125 221

 

Todd (127) examined further the relationship between the inhalation
of cigarette and cigar smoke. In general, cigarette. smokers who
switched to cigars were much less likely to report inhaling cigar smoke
than cigarette smoke; however, those who in the past reported inhaling
cigarette smoke a “lot” or “fair amount” were much more likely to
report inhaling cigar smoke to the same degree than those ex-cigarette
smokers who in the past did not inhale the smoke of their cigarettes.

This evidence has been confirmed by measuring carboxyhemoglobin
levels in former cigarette smokers who now smoke cigars or pipes.
Castleden and Cole (22) found that men who had smoked cigars or a
pipe, but who had not previously smoked cigarettes, had carboxyhemo-
globin levels similar to urban nonsmokers. However, men who had
switched from cigaréttes to pipes or cigars had levels comparable to
cigarette smokers. This was true even in those pipe and cigar smokers
who denied inhaling. Cowie, et al. (25,.26) found similar results in eight
subjects who had recently switched to cigars; seven subjects had
similar carboxyhemoglobin levels before and after switching from
smoking cigarettes to cigars. Smokers who inhale cigars have been
found to have carboxyhemoglobin levels even higher than those found
in cigarette smokers who inhale (46, 68).

Specifie Causes of Mortality
Cancer

Several prospective epidemiological studies have shown a significantly
higher overall cancer mortality among pipe and cigar smokers
compared to the cancer mortality of nonsmokers (Table 10).

Pipe and cigar smokers have much higher rates of cancer at certain
sites than at others. The upper airway and upper digestive tracts
appear to be the most likely target organs. The relationship of pipe and

13—20
cigar smoking to the development of specific cancers is summarized
below.

Cancer of the Lip

Approximately 1,500 new cases of cancer of the lip are reported each
year. Because of the possibility of early detection and surgical
accessibility of cancers in this area, there are less than 200 deaths from
cancer of the lip each year in the United States. Some of the earliest
scientific investigations exploring the association between tobacco use
and disease examined the smoking patterns of individuals with cancer
of the lip.

Broders (16) in 1920 examined the smoking habits of patients in a
retrospective study of 526 cases of epithelioma of the lip and 500
controls. Of the cancer cases, 59 percent smoked pipes, whereas this
was true for only 28 percent of the controls. No association was found
between cigar or cigarette smoking and cancer of the lip.

In a retrospective study of 439 clinic patients with cancer of the lip
and 300 controls conducted in Sweden, Ebenius (47) reported a
significant association between pipe smoking and cancer of the lip. A
total of 61.8 percent of the lip cancer cases smoked pipes, while only
22.9 percent of the controls smoked pipes. No association was found
between the use of cigarettes, cigars, or chewing tobacco and cancer of
the lip.

In other retrospective studies, Levin, et al. (80) and Sadowsky, et al.
(105) reviewed cases of cancer of the lip. In both studies, a strong
association was found between pipe smoking and cancer of the lip but
no significant association was found between the use of tobacco in
other forms and cancer at this site. Other studies support their findings
(70, 121, 142).

In summary, it appears that there are several factors involved in the
etiology of cancer of the lip. Among the various forms of tobacco use,
pipe smoking, either alone or in combination with other forms of
smoking, seems to be a cause of cancer of the lip. Table 11 summarizes
the results of these retrospective studies.

Oral Cancer

The lips, oral cavity, and pharynx are the sites most consistently
exposed to tobacco smoke. Data from the epidemiological studies
suggest that little difference exists between the smoking of cigarettes,
pipes, or cigars and the risk of developing oral cancer.

Hammond and Horn (52) examined the association between smoking
in various forms and cancer of the combined sites of lip, mouth,
pharynx, larynx, and esophagus. The mortality ratios were 5.00 for
cigar smokers, 3.50 for pipe smokers, and 5.06 for cigarette smokers,
compared to nonsmokers.

13—21
TABLE 11.—Relative risk of lip cancer for men, comparing

cigar, pipe, and cigarette smokers with nonsmokers.
A summary of retrospective studies

Relative risk ratio and percentage of cases

and controls by type of smoking

 

 

Author, reference Number
Non- Cigar Pipe Total pipe Cigarette .
: Mixed
smoker only only and cigar only
Broders (16): Relative risk 10.08 43 0
0 5387 Percent cases 7 19 41 1
Controls............... 500 Percent controls 4 16 6 26
Ebenius (41): Relative risk 10 a 41 05
Cages......eccceeseee es 439 Percent cases 49 6 41 4
Controls.............++ 300 Percent controls 65 12 18 10
Relative risk 10 «#419 29 14
148 ~~ Percent cases 15 27 48 45
554 Percent controls 22 2 2A 46
Relative risk 10,011 43 26 14 04
571 Percent cases 8 2 18 6 44 22
615 Percent controls 13 3 7 4 53 19
Relative risk 0 8 18 10 22
14 Percent cases 0 7 2 36 2
115 Percent controls 24 9 16 36 18
Relative risk 10 2... 004. 21 24
394 Percent cases Toe wee 2 3
912 Percent controls 18 ........ nl 61
Relative risk 10 «#14 4.0 26
301 Percent cases 7 2 6 1 60 6
265 Percent controls 17 4 3 0 53 0

 

 

1 Percentage based on less than 20 patients. Ratios: relative to cigarette smokers.

Doll and Peto (38) reported the mortality for all respiratory cancers
except lung and found mortality ratios of 9 for pipe and cigar smokers
who had never smoked cigarettes, 10 for pipe and cigar smokers who
had smoked cigarettes, and 14 for cigarette smokers.

A detailed analysis of oral cancer was presented by Kahn (69) who
differentiated between cancer of the oral cavity and cancer of the
pharynx. The mortality ratios for oral cancers were 1.00 for those who
never smoked, 3.89 for all pipe and cigar smokers, and 4.09 for
cigarette smokers. A further breakdown of the pipe and cigar smokers
demonstrated a mortality ratio of 4.11 for cigar smokers, 3.12 for pipe
smokers, and 3.89 for smokers of pipes and cigars. For cancer of the
pharynx, the mortality ratios were 1.00 for those who never smoked,
3.06 for all pipe and cigar smokers, and 12.5 for cigarette smokers. No
deaths occurred among those who smoked only cigars. The mortality
ratio was 1.98 for pipe smokers. Hammond (50) combined cancers of

13—22
TABLE 12.—Mortality ratios for oral cancer in cigar and pipe
smokers. A summary of prospective epidemiological

 

 

 

studies
Smoking type
Author, reference ; . : :
Non- Cigar Pipe Total pipe Cigarette .

: Mixed

Smoker only only and cigar only

Hammond and Horn! (52) 1.00 5.00 3.50 a 5.06
Doll and Hill? (88)........- 1.00 a Lee 39.00 14.00 10.00

Hammond (50) .......----++ 1.00 wee Lee 4.94 9.908

Kahn (69):
Oral! .......ceeeeeee renee 1.00 411 3.12 3.89 4.09
Pharynx .....cccecceeces 1.00 Lies 1.98 3.06 12.54

 

Combines data for oral, larynx, and esophagus.
2Figures for all non-lung respiratory cancers.
3Mortality ratios for ages 45 to 64 only are presented.
4Excludes pharynx.

the lip, oral cavity, and pharynx. The pipe and cigar smokers had a
mortality ratio of 4.94 and the cigarette smokers a mortality ratio of
9.90 compared to nonsmokers.

These studies are summarized in Table 12. They demonstrate that
smokers experience a large and significant risk of developing cancer of
the oral cavity compared to nonsmokers. This risk seems to be about

the same for all smokers whether an individual uses a pipe, cigar, or

cigarette.
Several epidemiological investigations have demonstrated an associ-

ation between the combined use of alcohol and tobacco and the
development of oral cancer. A few of these studies (71, 82, 83, 188)
contain data on pipe and cigar smokers. Heavy smoking and heavy
drinking are associated with higher rates of oral cancer than are seen
with either habit alone.

Cancer of the Larynx

Because of its proximity to the oral cavity, the larynx probably has an
exposure to smoke drawn through the mouth similar to that of the
buccal cavity and pharynx. Tobacco smoke that is not inhaled may still
reach as far as the larynx and upper trachea. Pipe and cigar smokers
develop cancer of the larynx at rates comparable to those of cigarette
smokers, i.e., several times those of nonsmokers. The similarity of the
mortality ratios of cancer of the larynx for smoking in various forms

13—238
suggests that the carcinogenic potentials of the smoke from cigars,
pipes, and cigarettes are quite alike at this site.

Several of the prospective epidemiological studies include data on
deaths from cancer of the larynx for pipe and cigar smokers as well as
for cigarette smokers. Hammond and Horn (52) combined data for
cancer of the larynx with cancer of the esophagus and oral cavity. The
mortality ratios compared to nonsmokers were 5.00 for cigar smokers,
3.50 for pipe smokers, and 5.06 for cigarette smokers. There were no
deaths from carcinoma of larynx among nonsmokers in the study of
British physicians by Doll and Hill (34), but the death rate for cancer of
the larynx among pipe and cigar smokers was 0.10 per 1,000 while the
death rate for cigarette smokers was 0.05 per 1,000. Kahn (69) reported
mortality ratios for cancer of the larynx of 10.38 for cigar-only
smokers, 9.44 for individuals smoking both pipes and cigars but not
cigarettes, 7.28 for all pipe and cigar categories combined, and 9.95 for
cigarette-only smokers. No deaths from cancer of the larynx occurred
in pipe smokers. Hammond (50) reported a mortality ratio of 3.37 for
all pipe and cigar smokers and a mortality ratio of 6.09 for cigarette
smokers in the age category 45 to 64. Wynder, et al. (137, 142)
distinguished between intrinsic and extrinsic larynx cancers.

Histologic changes of the larynx in relation to smoking in various
forms were described by Auerbach, et al. (7). Microscopic sections of
the larynx from 942 subjects were examined for the presence of
atypical nuclei and proliferation of cell rows. Sections were taken from
four separate areas of the larynx in each case. Among those who
smoked cigars and pipes but not cigarettes, only 1 percent had no
atypical cells and more than 75 percent of the subjects had lesions with
50 to 69 percent atypical cells. Four of the cigar and pipe smokers had
carcinoma in situ, and in one of these four cases early invasion was
seen in three of the sections. Of those who never smoked regularly, 75
percent had no atypical cells. The cigar and pipe smokers had a
percentage of cells with atypical nuclei similar to that of cigarette
smokers who smoked one to two packs per day.

Cancer of the Esophagus

The esophagus is not directly exposed to tobacco smoke drawn into the
mouth but it does have contact with tobacco smoke that is condensed
on the mucous membranes of the mouth and pharynx and then
swallowed. The esophagus is also exposed to a portion of tobacco smoke
deposited in the mucus cleared from the lung by the ciliary mechanism
or by coughing. Variations in inhalation of a tobacco product may not
appreciably alter the exposure the esophagus receives from smoke
dissolved in mucus and saliva. This possibility receives support from
the prospective and retrospective epidemiological studies which
demonstrate similar mortality rates for cancer of the esophagus in
smokers of cigars, pipes, and cigarettes.

13—24
TABLE 13.—Mortality ratios for cancer of the esophagus in
cigar and pipe smokers. A summary of prospective
epidemiological studies

 

 

Smoking type
Author, reference - 5 : .
Non- Cigar Pipe Total pipe Cigarette .
: Mixed

smoker only only and cigar only
Hammond and Horn! (52) 1.00 5.00 3.50 ce 5.06
Doll and Peto (38) 1.00 Leas a 3.70 4.70 9.0
Hammond (50) 1,00 wae Lee 3.97 4.172
Kahn (69) 1.00 5.33 1.99 4.05 6.17

 

1Combines data for oral, larynx, and esophagus.
2Mortality ratio for ages 45 to 64.

In the prospective epidemiological studies, cigar, pipe, and cigarette
smokers had similar mortality ratios for cancer of the esophagus.
Hammond and Horn (52) combined the categories of carcinoma of the
esophagus, larynx, pharynx, oral cavity, and lip and described
mortality ratios of 5.00 for cigar smokers, 3.50 for pipe smokers, and
5.06 for cigarette smokers. The 20-year followup of British physicians
(38) showed mortality ratios for cancer of the esophagus of 3.7 for pipe
and cigar smokers, 4.7 for cigarette smokers, and 9.0 for mixed
smokers.

Kahn (69) reported the following mortality ratios for smoking in
various forms compared to nonsmokers: cigar only, 5.33; pipe only,
1.99; pipe and cigar but not cigarettes, 4.17; all pipes and cigars
combined, 4.05; and cigarettes only, 6.17. The results of these
prospective studies are summarized in Table 18.

Several retrospective investigations have also examined the associa-
tion between smoking in various forms and cancer of the esophagus.
These studies suggest that cigar, pipe, and cigarette smokers develop
cancer of the esophagus at rates substantially higher than those seen in
nonsmokers and that little difference exists between these rates
observed in smokers of pipes and cigars and cigarettes.

Histologic changes in the esophagus in relation to smoking in various
forms were investigated by Auerbach, et al. (9).

Several retrospective studies conducted in the United States and
other countries have.examined the synergistic roles of tobacco use and
heavy alcohol intake on the development of cancer of the esophagus.
Four of these investigations contain data on pipe and cigar smoking
(15, 82, 83, 136). It appears that smoking in any form in combination

13—25
TABLE 14.—Relative risk of cancer of the esophagus for men,
comparing cigar, pipe, and cigarette smokers with
nonsmokers. A summary of retrospective studies

 

Relative risk ratio and percentage of cases

Author, reference Number and controls by type of smoking

 

Non- Cigar Pipe Total pipe Cigarette

 

smoker only only and cigar only Mixed
Sadowsky (105): Relative risk 10 48 38 51 38 33
Cases........... eee 104 Percent cases 4 5 3 6 60 18
Controls............... 615 Percent controls 13 3 7 4 53 19
Wynder (142): Relative risk 1003.1 21 cae 2.6 A
Cages.... 0... ccccee eens 39 Percent cases 13 15 18 tee 51 3
Controls. .............. 115 Percent controls 24 9 16 tee 36 13
Pernu (99): Relative risk 10 .... 30 tee 27 59
Cases.......ccccceeaee 202. += Percent cases Woo... 67 tee 59 18
Controls. .............. 713 «~Percent controls 39 .... 5 tae 5 7
Schwartz (113): Relative risk 10 .... (26 tee 11.7 86
Cases............0.0005 249 ~=—- Percent cases 2 .... 2 tae 88 7
Controls............... 249 «Percent controls 18 .... 7 67 q
Wynder and Bross
(186): Relative risk 10 «(3.6 9.0 6.0 28 37
Cases. i... ececeeeeee 150 Percent cases 5 19 9 4 51 i
Controls............... 150 Percent controls 15 16 3 2 55 9
Bradshaw and
Schonland (15): Relative risk 10 .... «48 tae 23
Cases... 20.0. 117 Percent cases HB .... «Ad Lae 63
Controls............... 366 Percent controls 32 .... 18 an 58
Martinez (82): Relative risk 10 20 7... 0 1, 15 2.2
Cases.......... eee eee 120 Percent cases 8 9 Lee vee 31 43
Controls. .............. 360 Percent controls 14 8 te nee 34 3A
Martinez! (83): Relative risk 10 2.0 28 tees 17 25
Cases........0.....0065 346 = Percent cases 21 10 15 teen 34 a4
Controls. .............. 346 «Percent controls 22 9 1 36 2

 

1This study combines data for oral cancer and cancer of the esophagus.

with heavy drinking results in especially high rates of cancer of the
esophagus.

Lung Cancer

Several prospective epidemiological studies have demonstrated higher
lung cancer mortality ratios for pipe and cigar smokers than for
nonsmokers, but the risk of developing lung cancer for pipe and cigar
smokers is less than for cigarette smokers. Table 15 presents a
summary of these prospective studies.

13—26
TABLE 15.—Mortality ratios for lung cancer deaths in male
cigar and pipe smokers. A summary of prospective

 

 

 

studies
. Smoking type
Author, reference : ; . :
Non- Cigar Pipe Total pipe Cigarette .
: Mixed
smoker only only and cigar only
Hammond and Horn (52). 1.00 1.02 3.00 tee 10.78 7.63
Doll and Peto (88).....-..- 1.00 tee tee 5.80 14.00 8.20
Best (11). ..--.-:eeeeeeeeeees 1.00 2.94 4.35 oo 14.91
Kahn (69)....c000--1es0eee 1.00 1.59 1.84 1.67 12.14

 

TABLE 16.—Lung cancer death rates for cigar and pipe smokers
by amount smoked

 

 

Smoking type Death rate per 100 Number of deaths
Nonsmoker.........-0cecsceerceeeteeesneeeessees 0.07 3
Cigar and pipe:
1 to 14g per day.....-..eseeereeeeeeereee 2 12
15 to 24 g per day.......-..eseeeeeree rere A5 6
QA g per day ........--ceeseeeeeeeeeeeeer sees 6 3
Cigarette only..........::eceeeeeereerereeteeees 96 143

 

SOURCE: Doll, R., (84)

Dose-response relationships such as those that helped demonstrate
the nature of the association between cigarette use and lung cancer
could not be as thoroughly studied for pipe and cigar smokers because
of the relatively few smokers in these categories. Although the number
of deaths were few, Doll and Hill (34) reported increased death rates
from lung cancer for pipe and cigar smokers with increasing tobacco
consumption (Table 16). Kahn (69) also demonstrated a dose-response
relationship for lung cancer by the amount smoked (Table 17).

A few of the retrospective studies contained enough smokers to
allow an examination of dose-response relationships for pipe and cigar
smoking and lung cancer (1, 81, 100, 105). These are summarized in
Table 18. An increased risk of developing lung cancer was demon-
strated with the increased use of pipes and cigars as measured by
amount smoked and inhalation. The retrospective investigation of

13—27