smoked. The study of Canadian veterans (9) also contained evidence
of a dose-response in mortality bv xwount s~noket! for cipr smokers.
So dose-response relationship was obsen-cd among pipe smokers (table
S). Kahn (50) reported a consistent increSxse in overall mortality
with an increase in the amount smoked for both pile and cigar smokers
(table 9). Hammond (38) found no consistent relationship between
overall mortality and the number of cigars or pipefuls smoked
(t.able 10).

TABLE 7.-hfortality ratios for lo!& deaths of cigar and pipe smokers by
         amount smoked-Hammond and Horn

      Number of deaths

Observed    Expected   hfannllty rsuo

Nonsmoker-~--~~~..----------------~-~~   1, 664    1,664        1. 00
Cignr only:
  TOt~l-~~~~-~-~-~~---~---~~-~--~--~~      653      593        1. 09
  1 to4 cigars-- _..___ -_----------_-_-      410      400        1. 03
  >4 cignrs- ____ -__-_-_---___-___--_-     229      185        1. 24
Pipe only:
  Total----------_-__._______________     609      560        1. 09
  1 to 10 pipefuls_--- __.. :_- _____ --_.-_     391      374        1. 05
  >10pipefllls---~-~~~-~---~~-- _-_._ --      204      172        1. 19

t3owca: Hammond. E. C.. Earn. D. (IO).

TABLE 8.-hforlality ratios for toti deaths oj cigar and pipe smokers
          by amount smoked-Best

Amount smoked

Observed

Number ol death

  Expected    Mortality ratio

Ncmmoker ___.___ ---- ________.____-
Cigar only:

Total _____ - ________ - ._.._-.--.-
1 to lOpipefuls_-_-_-- ______.___-
1010 20pipefd3-_--_- _______.-
>20pipefuls--- _____ - _______-.-

Gawa: Bat. E. W. R. (8).

90
64
23
1

570     566. 99        1. 00
374     370.09        1. 01
141     140. 84        1. 00
36      35. 90       1. 00

__-__-----       1. 00


  82.07        1. 10
  56. 05        1. 14
   19. 40        1. 19
   1. 59        . 63

551


The above evidence suggests that a dose-responx relationship map
exist between the number of cigars nnd pipefuls smoked and owrxll
mortnlit;o. However, becnuse of the high-mortnlity rate of ex-smokers
of cigars and pipes, it is difficult to interpret the data presented with-
out including this group with the continuing smokers. ll'ithout data
Fchich examines patterns of both daily rata of smoking and inhalation
at various age levels, no firm conclusions cnn be drawn ns to the nature
of this dosage relationship.

TABLE 9.---Mortdity ratios for total deaths of cigar and pipe smokers
        by age and amount smoked-Kahn

Amount smoked

Nonsmoker ______ ---__-- ________________________
cigar only:

  Total__-~__________-____________________~.-
  I to4cigarsperday _______ -_-_-- ____________
  5to8cigaraperday _______ ----__--- _________
  >S cigars per day ________ -- ________ ----_--__
Pipe only:

Total____~~~__-_________________________~-~
1 to 4 pipefuls per day _____ ---_- ______ -- _____
5ta 19pipefulsperday--_-- __.___.__ - _______
>19pipefufsperday ______ -- __._..__ - ___.___

1. 00

1. 01        1. OS
.89        1. 00
1. 14        1. 23
1. 65        1. 28

1. 08
1. 16
1. 04

1. 00

1. 06
.91
1. 10
1. 18

Boome: Kahn: H. A. (50)

TABLE lo.-Mortulity ratios for total deaths oj cigar and pipe smokers
        by amount smoked-Hammond

Amomt smoked

Amount smoked

Nonsmoker-----.-- _________   1. 00 Current pipe smokers:
Current cigar smokers:              Total __________ - _______._    1. 04
TOtal-_--- _-___ - ___.---.-    1. 09   1 to 9 pipefuls per day-__--    1. OS
1 to4cigarsperday ___.___    1. 03   >9 pipefuls per day ___.___     .92
>4 cigar3 per day__ _ __ _ _ _ _    1. 18

Boons: Hammond. E. C. (98).

552


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
only reaches the oral cavity and the upper digestive nnd respirator?;
tracts and does not reach the lungs where further direct effects and
systemic absorption of various chemical compounds cln occur.

L\]thougl~ the smoker has some voluntary control over the inhalation
of smoke, the physical and chemical properties of tobacco smoke to a
degree determine its acceptability and "inhalability."

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 xrter. Cigarette condensate is slightly acidic as measured
by this method. Since alkaline smoke is more irritating to the respira-
tory 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 (15)
have analyzed the pH of whole, mainstream smoke of cigarettes and
cigar; on a putf-by-puff basis using a pH electrode suspended in main-
stream smoke. Smoke from several U.S. brands of cigarettes Kas found
to be acidic throughout the entire length of the cigarette. Of intemst
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 M
percent of the puffs from the cigar. Available epidemiological evidence
indicates that most cigar smokers do not inhale the smoke and 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 t.hat influences inhalation patterns. Per-
haps "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 luns
when tobacco smoke is inhaled The amount of nicotine absorbed from
the lungs is primarily a function of the nicotine concentration in the
smoke and the depth of inhalation. Some nicotine may also be ab-
sorbed through the mucous membranes of the mouth. This is more
likely to occur under alkaline conditions rrhen nicotine is unprotonated
f3, 15, 79). This suggests that cigar smoker-s may he able to absorb
some nicotine through the oral cavity without having to inhale, par-
ticularly during the time that the smoke from the cigar is alkalme.

553


Jvith the development of sensitive measures of serum nicotine levels
(2) the extent to which nicotine is absorbed through t.he membranes
of the mouth in pipe and cigar smokers can be more awurately
determined.

Inhalation patterns of smokers Kere determined in several of the
large prospective and some of the retrospective epidemiologiul studies.
Inhalation was usually determined by the administration of n que-s-
tionnairo that required a subjective evaluation of one's orrn patterns
of inhalation. Although the accuracy of these questionnaires has not
been confirmed by an objective measure of inhalation, such as carbosy-
hemoglobin or zrum 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 (26) and Hammond (38) presented information on
inhalation patterns of pipe, cigar, and cigarette smokers (figs, 1,2, 3,
and table 12). Some 80 to 90 percent of cigarette smokers reported
inhaling, Kith the majority of individuals inhaling moderately or
deeply, rrhereas most pipe and cigar smokers denied inhaling at all.
Pipe smokers reported slightly more inhalation than cigar smokers.
For each type of smoking, less inhalation n-as 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
19.57, periodically reported the use of tobacco products by the British.

figure I.--Inhalation among pipe smokers by age.

  No
inhalation

Some
inhaiahon

      I                              I
   Age     40         50        60        70         80
SOURCEr Hammond, E C. (38).

554


Figure 2.-Inhalation among cigar smokers by age-Hammond.

c---

3"1,1C
inhalation    26.4       22.9      17.1       13.7       18.5  I

     Age 40        50        60        70        80

SOURCE: Hammond. E. C. (38).

Figure 3.-Depth of inhalation among cigarette smokers by age.-Hammond.

None

Slight
inhalation

Moderate
inhalation

Deep
inhalation

      Age 40        50         60        70        80

SOURCE: Hammond, L C. (381.

Recent reports edited by Todd h ave contained data on the inhalation
patte.rn of cigar, pip, and cigarette smokers (92, 93, 94). Table 11
shows that most, cigarette smokers inhale a "lot" of "fair amount"
whereas most pipe and cipzr smokers do not inhale at all or "just a
little." Little change is observed in the inhalation patterns of.8 given
product since 11)66.

Best (9) reported inhalation data among male cigarette smokers by
smoking intensity and age group, but did not report the inhalation

555


patterns of pipe nnd cigar smokers. The overall mortality rates of
current pipe smokers who inhaled at least slightly were reported by
Hammond (38) as being someThat higher than for men rho never
smoked regularly. The overall mortality rates of current ci.gar smokers
who reported inhaling at least slightly xrere appreciably higher than
for men who never smoked regularly (table 13).
Available evidence indicates that cigarette smokers inhale smoke
to a greater degree than smokers of cigars or pipes. Once a smoker has
learned to inhale cigarettes, however, there appears to be a tendency
to also inhale the smoke of other tobncco products. For cigars, this is
evidently true lx-hether one smokes both cigarettes and cigars or
s-x-itches from cigarettes to cigars (tables 14,15,16).
Brass and Tidings (14) examined the inhalation patterns of
smokers of large cigars, cigarettes, and those who switched from one
tobacco product to another (table 15). Nearly 75 percent of those who
were currently smoking only cigarettes reported inhaling "almost every
puff" and only 7 percent never inhaled. The opposite was true for per-
SOIIS who had always smoked only cigars among whom 4 percent re-

TABLE 1 I.-The eztiru! of inhaling pipes, cigars, and cigareties by
     British males aged 16 and over in 1968 and 1971

Tobacu, product

Inhale a lot __._____________._______   23    19    8    8    47    47
Inhale a fair amount _____ --- .______ -   16    19    10     8    31     30
Inhale just a little _________ - ________   27    27    24    26    13     15
Do not inhale at all__ ______.________   34   35   59    58    9     8
                                                      -

    Total___________~__--~-------  100   100   100   100   100    100

Soum: Todd, 0. F. (95. 9)).

TABLE I2.---l&a&ion among cigar, pipe, and cigareb smokers by
           age-DoU and HiU

smoking type

Cigar and pipe ___.____________  12. 00  10. I10   7. 00   5. 00   4. 00    4. 00
Mixed (cigarette and other)_-__ _  74. 00  60. 00  47. 00  36. 00  30.00   26. 00
Cigarette only _.______________ 90.00  85.00  75.00  66.00  58.00   41.00



8ourcr: Doll, R.. HIU, A. B. (Ib).

556


ported inhaling almost ore? puff and 83 percent said they nerer
inhaled. Cipr smokers rho also smoked cigarettes reported inter-
mediate levels of inhalation betwcn the cigar onlr and ciprette onI?
categories. Inhalation patterns wrc similar rrherher the individual
continued to smoke both products, stopped smoking cigarettes but
continued smoking cigars, or stopped smoking cigarettes  nnd
sxitched 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 mny be more likely
to inhale cigar smoke if he sxitches to cigars, or uss both cigars nnd
cigarettes, than the cigar smoker who has not smoked cigarettes.
Todd (93) reported similar data for a sample of smokers in the
United Kingdom (tabIe 16). The prevalence of inhaling a "lot" or
"fair amount" of smoke xx-as hi,nhest among cigarette smokers who were
currently smoking cigarettes (77 percent) nnd lorrest among current
cigar smokers who had previously smoked only cigars or pipes (18
percent). Indiriduals who switched from cigarettes to cigars main-
TABLE 13.-Mortality ratios jar total deaths oj cigar and pipe smokers
        by age and inhalation-Hammond


                                          Mortatltr rslb. age
                 Inhalation                    4.3 to 64     a5 to 64


Nonsmoker-__-_______---~--~----~~---~-~~--~-------     1. 00      1. 00
Cigar only:
  Totel---__-_______--____________________--~~-~~     1. 09       .98
  No inhalation _____ - _______________________ -----_     1. 02       .91
  Someinhalation~__-___-_-____________________---     1. 29      1. 37
Pipe only:
  Total---____--____-_____________________--~~-~-     1. 04       . 95
  No ihabtion ____________ --- ____._._____________     . 98      _ 87
  SOme inhalstion_-__-_-__-____________________---     1. 21      1. II


E%~: -mmond. E. C. (~8).
TABLE 14.--Percentage oj Bn'tish male cigar smokers who reported
  inhuling a lot or a jair amount by type bj product smoked



         T9ce of product                1963             1971

                            Number of   PWWnt   Sumkr of   Percent
                            In&ridu&         In&rlduals

%m only.. _ _. _____ -_ __ ____ .____._     706   23. 0
%a~ and cigarettes__--. . ___ ______._                    111     27. 0
                       1,193    42. 0      277    44. 0
CiRam and pipes.----_--- ..__________     596    35. 0      109    32. 0
cigm, cigaretteu, and pipes ._________      26    52. 0       1.5    32. 0

EOUrcC: Todd. 0. F. (0,. 04).

                                         557


tained somewhat higher levels of cigar smoke inhalation than those
cigar smokers n-ho had never smoked ci,narettes (30 percent).

Todd (93) examined further the relationship between the inhalation
of cigarette and cigar smoke. In general, cigarette smokers who
switched to cigars rrere much less likely to report illhaiing 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 cignr smoke to the same degree than those ex-
cigarette smokers who in the past did not inhale the smoke of their
cigarettes (table 17).

TABLE IL-Percentage of indiuidua!s reporting inhulation of "almost
erery puff' of tobacco smoke by current and previous tobacco usage and
type of tobacco used

Cigarettea only ____ Cigarettes only ____ 2, 359  Cigarette-_-  74. 8  73. 1  76. 6
Cigars only- _ _-___ Cigars only- _ _ ____   649  Cigars..----  4.5   3. 0   6. 0
Cigarettes and    Cigarette-s and      520 w-.--do ____ -  20.4  10.5  28.0
cigars.        cigara. _
Cigars- _ - - _-__ _ __ Cigarettes and       93 __.__ do-_---  18.3   9. 0  30. 0
            cigars.
None ____________ Cigarettes and      186  ____ -do----- 21.5  17.8  24.2
            cigars.
Cigars-- __ _____. _ Cigarette3 only ____    64 _____ do _____  17.2  16.0  28.0

Bourcs:Brcar. I. D.J., Tidlnpr,J.(10.

TABLE 16.-percentage of British males who reported inkding a lot or
jair amount of n'gar smoke by current and previous tobacco usage and
type of tobacco previously smoked (1968)

CigaretW only--- - _ _ _ _ Cigarettes only-_-_- -  2,`586  Cigarette.- _ __    77. 7
Cigars only __-___-.___ Nonsmoker- ____ _-__   306 Cigars------_    18. 0
Cigars only ____-_______ Cigarettes only _.___._    321 -----do-__.-.-    30. 0


&xma: Todd. 0. P. @I.

558


TABLE 17.-Extent O_r rt-ported inhafaiion qf cigar smoke by British
male cigar smokers who were ez-cigaretfe smoL-crs in I.%T, artalyzcd
by extent of reported inhalation of cigarette smoke when yrt-ciously
smoking cigareUEs

                                      or fRIT amount   or not 81 au

                                           P<rrCmLt       PClCd
Inhalealotorfairamount _____. - .____ --___- ____.      44. 0        5. 0
Inhale a little or not at all__- _______ ---- __._____._      56. 0        95. 0

Source: Todd, 0. F. (89.

Specific Causes oi

i?fortamy

Cancer

Several prospective epidemiological
              .~

studies have showr a signifi-

cantly higher overall cancer mortality among pipe and cigar smokers
compared to the cancer mortality of nonsmokers (table 18).

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 cigar smoking to the development of specific cancers is detailed
in the following sections.

TABLE lg.-Mortality ratios jar total cancer deaths in cigar and pipe
  smokers. A ammary of prospective epidemiological studies

            Type of smoLlng

Nonsmoker Cigar only  Pipe only  Total pipe
                      and cigar

1. 00     I. 34     1.44  __------     1. 97
1. 00     1. 13     1.38  -___--.-     2. 06
1.00   _____--  -------    1. 21      1. 76
1. 00     1. 22     1. 25     1. 25     2. 21

559


Cancer of the Lip

Approximately 11500 nerr cases of cancer of the lip are reported
each year. Because of the possibility of early detection and surgicai
accessibility of cancers in this area, there are leas than 266 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 pntterns of individunls with cancer
of the lip.

Broders (13) in 1920 examined the smoking habits of patients in
a retrospective study of 546 cases of epithelioma of the lip and 500
controIs. Of the cancer cases, 59 percent smoked pipes, whereas this
was true for only 28 percent of the controls. No association xas found
between cigar or cigarette smoking and cancer of the lip.
In a restrospective study of 439 clinic patients with cnncer of the
lip and 300 controls conducted in Sweden, Ebenius (32) 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. So associntion Kas
found between the use of cigarettes, cigars, or chewing tobacco and
cancer of the lip.

In other retrospective studies, Levin, et al. (I%) review-ed a series
of l-13 cases of cancer of the lip, and Sadowsky, et al. (77) reviewed
571 cases of cancer of the lip. In both studies, a strong association n-as
found between pipe smoking and cancer of the lip. No significant
association T<as found betlreen the use of tobacco in other forms and
cancer at this site.

In a study of environmental factors in cancer of the upper alimen-
tary tract, Wynder, et al. (113)  f ound an .association betmeen pipe
smoking, cigarette smoking, and cancer of the lip. There were only 15
cases of cancer of the lip in this study.

Staszen-ski (87) examined the smoking habits of 394 men with
carcinoma or precancerous lesions of the lips. An association eras
found between the smoking of pipes and cigars and cancer of the lip,
but this was only of doubtful significance. A significant association
was found between the use of cigarettes and cancer of the lip.

Keller (51) conducted a study of lip cancers in which he considered
a number of factors including histologic types, survival, race, occupa-
tions, hnbits, and associated diseases. A total of 301 patients with
primary basal cell or scluamous cell carcinoma of the lip and 301
controls from the same hospital matched for age and race were con-
sidered in this series. il significant association was found betxeen
smoking in all forms and combinations and carcinoma of the lip. It
\vas also found that increasing age and outdoor occupations with
exposure to the sun were equally significant factors in the etiology of
lip cancer.

560


In summary. it appears that there are several factors involved in
the etiology of cancer of the lip. 2-2mon.g the various forms of tobacco
use, pipe smoking either alone or in combiJJation with other forms of
smoking seems to be a cause of cancer of the lip. Table 19 summarizes
the results of these retrospective studies.

Oral Cancer

The lips, oral cavity, and pharynx are the first tissues exposed to
tobacco smoke d=rTvn in through the mouth. Varintions in inhalation
(Iuhng t.he smoking of various tobacco products result in different pat-
teJ-Jis of distribution of srJJoke throughout the respiratory tree. How-
ever, the oral cavity and adjacent tissues are the sites most consistently
exposed to tobacco smoke. For this reason, differences in inhalation
should result in less variation in exposum to tobacco smoke for these
sites than for t-he lower trachea and the lung. The inherent carcinogen-
icity of pipe, cigar, and cigarette smoke is most reliably compared at
those tissue sites where dosage and exposure to tobacco smoke are most
nearly equal. Data front the epidemiological studies SU~~CS~ that little
difference exists between the smoking of cigarettes, pipes, or cigars and
the J-isk of developing oral cancer.

Hammond and Horn (40) examined the association between smok-
ing in va~-ions forms and cancer of the cornbind 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
cornpared to nonsmokers. -111 the deaths from cancer of the lip, oral cav-
ity, and pharynx reported by Doll and Hill (26) occurred in smokers.
The death rates from cancer at. these sites were 0.M per 1,000 for pipe
and cigar smokers, 0.10 per 1,000 for mixed smokers, and 0.05 per 1,000
for cigarette smokers. ,I fairlv detailed analysis of oral cancer was pre-
seJJted by Kahn (SO) who differentiated between cancer of the oral
cavity and CaJJcer 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 thJzr
pipe and cigar smokers demonstrated a mortality r;ttio of 4.11 for
cigar smokers, 3.12 for pipe smokers, and 4.20 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.. So deaths occurred among those lvho smoked
oJJly Cigars. The mortality ratio was 1.98 for pipe smokers and 7.76
for sJnokem of pipes and cigars. Hammond ($8) combined cance-s of
the lip, ora1 cavity, and pharynx. The pipe and cigar smokers had a
mortnlity ratio of 4.94 and the cigarette smokers a motility J-at,io of
9.90'compared to JJoJisJnokers.

561


Brodcrv (19):
  C~CY..-...--_-_------------ 537
  CurltrulY.. _--__-_-----_---__- 500

Ebcniw (Yg) :
  CUBCYy __-_-__-----_--_------ 439
  Cuntrols ____________________ 300

Lcvin, ct rrl. (60):

cuscs-........-....--------- 143
CurltrulY _-_______----_----__ 554

Sadowaky, ct ul. (77):
  CUSCY~ - ._ ._-. -_ _____________ 671
  Cuntruly- _ _ _ _ __ _ _ ___ _ _ _. _ _ _ _ G I5

Wyndcr,' CL al. (123):
  Casts- -_---_-------- ------_-  14
  Controls-----..-.-.--------- 115

Stnszcwski (87) :
  C UY(1Y - - _ _ - - - _ - _ _ _ _ _ _ _ - _ _ _ _ _ _  394
  Cuntrols ________.____________ 912

Kcllcr: (61) :

cuscs- - - - - -- - - - _ - - -- -_ _ _ _ _ _ _  301
Controls _____________________ 2G5

Rclativc risk ____________
Percent ca~cs ___________
Percent corrtrolv .________

Rchtive rwk. __._________
Percent casts ___________
Pcrccnt controlv _________

Rclntivc risk ____________
I'crccnt CIISI:Y- _ _ _ __ _ __ _ _
Pcrccut control3 _________

Rchtivc rbk ____________
Percent cwc3 ___________
Percent controla. ________

Rcletivc risk ____________
Pcrccnt cam _______ _____
Pcrccnt controh _________

Rclntive rivk _______ _____
Pcrccnt cnscs _______ _____
Pcrccnt controlu _________

1. 0     0. 8
7      19
4      16

1. 0      7
49    6'
65      12

1. 0     1. 9
15      27
22      20

1. 0     1. 1
8       2
13      3

0       8
0    7'
24      9

1. 0  _ _ _ _ _ _ _ _ _
i   _ _ _ _ _ _ _ _ _
13 ___-____-

1. 0     1. 4
7       2
17       4

4. 3 - -- --- -
     -      -     0   - - _-. . -. -
41 --_____-_     1   __---_- _-
G   em-m...-*   2G   _ _ _. -. - - -

  4. 1 0.5  ____- __  ____ -_--_
41 4    _....__ .____--__
13 10    ____-__  ___-__-__

2. 9 _. . - - _ - -
          -      1.4  _______ __
48 -..--_--_    45   -- ._---._
24 _.______ _    46   _____ ___
                       _

  4. 3 2. 0     I. 4      0. 4
18 a      4 *1       2') *
  7 4      53       19

  1. 8 - _ - _
       - _ - _ _     I. 0      2. 2
29 - _ _ _ _ _ - _ _    36       29
16 -----____    36       13

- - - - - - _ 2. 1     2. 4  _ - - - - _ - _ -
-____-_ 12      73  _____----
-.--we-     ll      61 _________

  4.0           2. a
  I3       1      GO       G
  3 0      53       0


These studies are summarized in table 20. Ther demonstrate that
smoke.rs experience a Jar.3 and si,?ifcnnt risk of dere1opin.g cnnwr
of the oral cavity compared to nonsmokers. This risk seems to he &out
the same for all smoker; whether an indis-idusl uses a pipe, cigar, or
cigarette.

  A number of retrospective studies hnre esnmined the relationship
betwen smoking in various forms and cancer of t.he oral carit_r. The
results of these studies are pwsented in table 21. Some of the variations
in relative risk of developin g oral cancer observed in the rdrospwtive
studies is probably duo to t.he lack of suniform definition of oral cancer
by anatomical site and the various means used in select.ing and defin-
ing cases and controls. It appears, however. that R significant risk of
dereIopin,rr oral cancer exists for smokers compared to nonsmoker;
and this risk is similar for smokers of pipes, cigar;, and cigarettes.
  Several epidemiological investigations have demonstrated an asso-
ciation betrreen the combined use of alcohol and tobacco and the
dcvciopment of oral cancer. ;I few of these studies (59, 62, 63, 109)
contain data on pipe and &Far smokers. Heavy smoking and heavy
drinking are associated xTith higher rates of oral cancer than are seen
with either habit alone.

TABLE %I-Mortality ratiosjor oral cancer in cigar and pipe smokers.
    A summary of prospuztive epidemiological studies

IIammond and Horn'(40)-   1. 00    5. 00    3.50 ~_______   5.06 -: -..___
Doll and Ffill~ (PC?, .S'7)_ _ _   0.00 --.---__  ~-----   0. 80    1. 00    2. 00
Hammond (58)-_--__--__   1.00 _-__-_-_  -_-___   4 94   `9.90 -----.--
Kahn (60):
  Ora14_._____ -__-___   1. 00    4. 11    3. 12   3. 89    4.09 _- ______
  Pharynx ________ --r-   1.00 --_.----   1. 9a   3. 06   12.54  - _______

Cancer of the Larynx

The larynx is situated at t.he upper end of the trachea. Because of
its proximity to the oral cavity, the larynx probably hxs a similar
exposure to snloke drawn through the mouth as the buccal cavity and
pharynx. Tobacco smoke that is not inhaled may still reach a~ far as
the lnrj-ns and upper trachea. Pipe and cigar smokers develop cancer
of the larynx at rates compnnble to those of cigarette smokers. These

563


TABLE 21 .-Rcloriue risk of oral cancer for men, comparing cigar, pipe, and cigarelle smokers uith nonrmokers. A summary of rcfrospeclive
                                       sludies

hlillr and Porter (6G):
  CayCY~~~~.~..~.~~~~~~~~~~~~~   124
  Controls- _ _ _ _ . _ _ _ _ _ _ _ - _ _ _ _ _ _ _   185

Sadowsky, et al. (77):
Casey----..._----....._-__.- 1,136

Controls..- _ _______ ._________

615

Schwartz, et al. (89) :
  Cases.---.-.-.--------------
  Controls ____ ___ ____ __ __ ______

332
608

Wynder, et al. (109):
  CayCE..-----....-_----------
  Controls.. _ - _ - - _ _ _ _ _ _- _ _ _ _ _ _ _

Wynder, et al. (f IS):
  Cases.------..---._---------
  Conbrols ___-_______ .__ -m--m__

543
207



115

115  Percent controls __________

Relative risk _____________
Percent casc3 ____________
Percent controls.-- _ _ _____

Relative risk _____________
Percent cases- _ __________
Percent controls __________

Relative risk _____________
Percent cases- __ _________
Percent controls. _________

Relative risk _____________
Percent cuscs ___________.
Percent controls __________

Relative risk ____ _ _ _ __ __ __
Percent cnscs ____________

1.0  _-_______  _--_____    7.0
10   _-_------  _-____-_    55
38   _________  ________    30

1. 0     2. 0
8       4
13      3


1.0 ___--.___
16 _-__-_---
23      77


1. 0     3. 6
3      20
10      13


1. 0     1. 7
23      13
26      9

4.4  _________
18   _________
7   -_-______

1. 0 - - _ - - -
       - - -
3   -- -
     ----_-
3   _ - _ - _ _ _ _ _


0. 1  - - - - - - - _ -
11   _________
G   -e----e--


.9  _^______-
12   ________-
16   ----q-q--

4. 1  - - _ _ _ - - _ -
36   ____.____
32   -____-__-


1. 4      2. 1
42      28
53       23

1.5  ___------
63   _________
58   -_.-.----


3. 0      3. 3
57       8
63       8

1. 2      1. 4
37       IG
36       13


Wyndcr, ct sl. (II@:

$    C8.W! _ - _ - _ - _ _ _. _ _ - _ _ _ - _. _ _. -   178
   Controls _.__ _ _ _ _ _. . __ _ _ _ _ _ _ _ _   220

ifi
! Pcmu (73):
   Cnaev ______________._____--- 1,400
   Con trCJL_ ____ _ _ _ - _ - - _ _ ^ _ _ - - - - -   713

: Staazewski (87):
   CaSW...-----....-._.-------   383
   Controls ________ __ ___________   912

Keller (at) :
   Casea--....-..---...-.------   408
   Controls _____________________   408

hfsrtinez (08):
   Crises _ _ _ _ _ _ . . _ _. _ _ _ _ . _ _ _ _ _ _ _   170
   Controls _____________________   510

hlartinez 1 (8s) :
   Cnses. _ _ - _ _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ _ .   346
   Controls ._______ __. ____ ___ ___   346

R&live rbk _________.___
Pcrccnt cazics.. _ ___ ______
Pcrccnt controls __________

Rclutive risk _._______.___
Pcrccnt cilscs ---__-____._
Perccn t controls. _ _ _ _ _ _ _ _ _

Relative risk _____________
Percent cases ____________
Pcrccn t controls. _ _ _ _ _ _ _ _ _

Relative risk _____________
Pcrccnt casts ____________
Pcrccnt control3 ____ __.___

Rclativc risk _____________
Percent ca3c9-- _ _________
Percent controls __________

Relative risk _____________
Percent cases _______: ____
Percent controls __________

1. 0     6. 0  _ _ . _ _ _ _ _  _ _ _ _ _ _ _ _
4      33    _---.---  -_--____
10      22    _____-_-  -.-*_-__

4 0 _ _ _
    - _ - _
       _ -
4.5   _ __ _
    - - _.
        -
45   _. _ -. _ - _ -

2. 2      2. 9
50       11
60       7

3. 6  _ _ _ _ _ _ _ _ _
72   _ _ _ _ _ _ __ _
61   -________

3. 4  -. - _ _ -
      - _ _
69   _ _ _. - - - -
     _
56   _. _ _ - _
       -  - -

I. 5      23
39       34
44      25


1. 7      2. 5
34      34
3G      25


rates are several times the rates of nonsmokers. The similnritr of the
modality ratios of cancer of the larynx for srnoki~~g in \-arions forms
suggests that the carcinornznic potentials of the smoke from cigar;.
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 SII~O~~IX FIS ~~11
as for cignrette smokers. Hammond nnd Horn (40) 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 cigsr
smoker;, 3.50 for pipe smokers, and 5.06 for cigarette smoker; There
Kern no deaths from carcinoma of larynx among nonsmokers in
the study of British physicians by Doll and Hill (86') ; holrevcr, the
death rate for cancer of the larynx among pipe and cignr smokers KS
0.10 per 1,000 while the death rate for cigarette smoker-s uas 0.05 per
1,000. Kahn (50) reported motility ratios for cancer of the larynx of
10.33 for cigar smokers, 9.44 for pipe and cigar smokers, 7.28 for all
pipe and cigar categories combined, and 9.95 for cigarette smokers. Xo
deaths from cancer of the larynx occurred in pipe smokers. Hammond
(38) 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. These studies are. summarized in table 22.

Several retrospective studies have examined the smoking habits of
pntients with cancer of the larynx and appropriately matched controls.
The small number of pipe and cigar smokers in each study results in
relative risk ratios that are quite unstable; however, it appear-s that
pipe and cigar smokers experience a risk of developing cancer of the
larynx that is similar to the risk observed among cigarette smokers
(table 18).

TABLE 22.~MurfaIity ratios for cancer of the larynz in cigar and pipe
  smokers. A ammary of prospective epidemiologid studies

Bammond and Horn 1
(f#O)-- _____.__.._____ -   1. 00    5. 00   3.50 --_-_.__   5.06 -..- ____
Doll and Hill * (es, .$7).-_   0.00 -..-~-..  -_._-_   2. 00    1. 00    0. 60
Hsmmond (Q8)- ____ - _.__   l.oo- -___ --_  -_._-_   3. 37   ' 6.09  -.---___
Kahn (60). _ _._______ _-_   1. 00   10.33   --__-_   7. 28    9.95  -.-__-._

566.


WJnder, et al. (108, 213) distinguished betxwen intrinsic and es-
trinsic larynx cancers. For smokers the relative risk of developing
cancer of the intrinsic lnrgns was similar to the relative risk of lung
cancer whereas the relative risk of developing extrinsic larynx cancer
-XBS more like the relative risk of cancer of the upper digestive tract.
fIistologic changes of the larynx in relation to smoking in various
forms were described by huerbach, et al. (5). Microscopic sections of
the larynx from 342 subjects were exnmined for the presence of
atypical nuclei and prolifemtion of cell ro\ys. Sections were t&en
from four separate areas of the larynx in each case. Among t.hose 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
Gth 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
Kas seen in three of the sections. Of those -ho never smoked regu-
Iariy, 75 percent had no atypical cells. The cigar and pipe smokers had
a similar pe.rcentage of cells rrith atypiwl nuclei as cigarette smokers
who smoked one to two packs per day. IVith respect to the prolifera-
tion of cell rows in the basal layer of the true vocal cord, the least
proportion of cases with eight or more cell rows E-as found in men
\Tho never smoked, and the greatest proportion was found in heavy
cigarette smokers. Pipe and cigar smokers had a distribution of cell
rows that was comparable to that of cigarette smokers who consumed
about a pack a day.

Several retrospective studies have reported an association between
the combined use of tobacco and alcohol and cancer of the larynx. A
stud? by Wynder, et al. (108) included some information on pipe and
cigar smoking in relation to drinking habits and the development of
cancer of the laryns, but. because of t,he limited number of pipe and
cigar smoking subjects this relationship could not be adequately
determined.

Cancer of the Esophagus

The esophagus is not directly exposed to tobacco smoke drawn into_
the mouth; however, the esophagus does have contact with that portion
of tobacco smoke that is condensed on the mucous membranes of the
mouth and pharynx and then swallowed. The esophagus is also ex-
posed to a potiion of tobacco smoke that is deposited in the mucus
cleared from the lung by the ciliary mechanism or by coughing. Varia-
tions in inhalntion of a tobacco product may not appreciably alter the
exposure the esophagus receir-es from smoke dissolved in mucus and
saliva. This suggestion receives support from the prospective and
retrospective epidemiological studies which demonstrate similar mor-
tality rates for ctiucer of the esophagus in smokers of cigars, pipes, and
cigarettes.

567


TABLE 23 .-Relutive risk of cancer of the larynx for men, comparing cigar, pipe, and cigarette smoker8 with nonsmokers.
                 A summary of retrospective StUdie8

Schrek, et al. (81):
  casts -___-- ________.________  73
  Controls _-___________________ 522

Sadowsky, et al. (77):
  Cases-.-..-.--_---..-------- 273
  controls _________-__*________ 615

Wynder, et al. (108):
  cases_~-.._...._~--.-~---~~~ 209
  Controls ____________.________ 209

Wynder, et al. (119):
  Cases-._.--_.--_..-.-------- 60
  Controls __________________. __ 271

Wynder, et al. (1f6):
  Cases _______________________ 142
Controls __--__________ I______ 220

Relative risk __.________ _
Percent cases- __________
Percent controls _________

Relative risk ____________
Percent cases- _ _ _ _ _ _ _ _ _ _
Percent controls _________

Relntivc risk ____________
Percent cnscs. ________. _
Percent controls _________

Relative risk ____________
Pcrccnt cases. _ _ _ _______
Pcrccnt control3 _________

Relative risk ___________
Percent cases- __________
Percent controls _________

1. 0     0       1. 1  _ - _ _ _ - _ - _
14      0      7   ----_----
24      10      11   -_.._____

2. 3  _ - - - - - - _ _
80   - _ _. _ _ _ _ -
59   _ _ _ - _ - _ _ -

1. 0     2. 2     2. 3  _ _. _ _ -
                     - - _
4       2       5   s-_-_-e_-
13      3       7   --_--____

3. 7      4. 1
GO      29
53       23

1. 0     15. 5    27. 7    11. 1
11' 5  10 8   5 4   2 1

24. 6  _ _ _ - _ _- _ -
XG   - _ _. _ - - _ -
74   _ _ _ _ _ _ _ _ .

1. 0     9. 7     4. 5  - - _ _
                   _ - _ - -    6. 3      6. 3
5      17      15   - -------_    47       17
24      9      16   - _ - - _ _ _ _ -   36      13

1. 0    14. 5     16.0  .________
1      20       1   --.--e-_-
16      22       1   .-m-_-m_-

22. 0     1G. 0
G2       16
45      16


Pernu (79) :                    Relntive risk _______.____    1.0  ______-__    45  -.-------    8.7      3. 2
  CaYeY..........--..---.-----  546    Pcrccnt cues __.________    7   ___._____    4   ____r____    78        4
  C~~nlrob ._._____________ _____ 713    Pcrccnt contrulu __-______    30   - _ _ - - - -
                                                           - -       5   --------_    50       7

Starzcwski (87):                 Rclntivc rirk ____________     1. 0  _________  _______    6. Q    50. 2 - __ - - - - - -
  Casca..-..._-..-.-..--------  207    Percent cIwes ___________      5  _________  ._____-    2      88   w-_-m-.-.
  Controls _____________________ 912    Percent control.4 _________    17  __`_._____  _______    11      01   --__--_--

Svoboda ($0) :
  C~CS...---............----.  205
  Contrh __.__________________ 320

Relative rivk ___-___.____
Percent cwey-.- ________
Percent controls--- _ _ _ _ _ _

1.0  _____-___     2. 0  - - _ _ _ _
                  _ _ _       10. 0  _-__-----
3   ____---__    3   .--------    05   _ _ -. _ - _ - -
22   ___--_-__    7   --___----    71   _- __ -----

Stell (88) :                    Rclntive risk ____________    1. 0 - - _ - _ - - _ -   - - _ - - - -    1. 3     2. 4  _ - - _ - - _ - -
  Cases-----..._.-.-.---------   190 Percent cILses.. _ _________   I1 _____ ____ ______.    8      79   - _ - _ - _ _ _ _
  Controls. ____ _ ____ ___________   190 Percent controls _________ 17 _________ _______ 10      50   - _ _ _ - - - - -


in the prospective epidemiological studies, cigar, pipe, and cigarette
smokers all had similar mortality ratios from cancer of the esophagus.
fIan\mond and lrorn (40) combined the categories of carcinoma of
the esophak?ls. i:lr~-AS, phnnnx, oral cavity, and lip and described
n~o~a~ity ratios of 3.00 for cigar smokers. 3.50 for pipe smokers, and
5.06 for ciprette smokers. Doll and Hill (26) reported an esophageal
Lancer mortality ratio of 2.0 for pipe and cigar smokers, 4.8 for mixed
smokers. and 1.5 for cigarette smokers. Kahn (30) reported the fol-
lolving mortality ratios for smoking in various forms compared to non-
smokers: cigar only, 5.33; pipe only, 1.99; pipe and cigar, 4.17; all
pipes and cigars combined, 4.05; nnd cigarettes only, 6.17. The r~~1t.s
of these prospective studies are summnrized in table 24.

Several retrospective investigations have also examined the associa-
tion betrreen smoking in various forms and cancer of the esophagus.
These studies have been summarized in table 2% The evidence sug-
gests that cigar, pipe, and cigarette smokers develop cancer of the
esophngus at rates substantially higher than those seen in nonsmokers,
and that little difference exists bet-ween these rates observed in smokers
of pipes and cigars and cigarettes.

Histologic changes in the esophagus in relation to smoking in vari-
ous forms rrerO investigated by -4uerbach, et al. (7), who looked for
atypical nuclei, disintegrating nuclei, hyperplasia, and hyperactive
esophageal glands. ,4 total of 12,598 sections were made from tissues
obtained from 1,968 subjects. For each of t.he parameters investigated,
pipe and cigar smokers demonstrated significant.ly more abnormal
histologic changes than nonsmokers; horrever, these changes were not
;LS severe or as frequent *as those seen in cigar-et te smokers.

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
(12, @,6s1 107). It appears that smoking in any form in combination
with heavy drinking results in especially high rates of cancer of the
esophagus.

TABLE 24.--lliorta&! ratios for cancer of th.e esophagus in cigar and
lvipe smokers. A wmmy qf prospective epidemiologica.! studies

Author, reference

ClglU
O&Y

T0W.l   Cigarette
Pfpe=d   OnJY    Mlred
cinar

Hammond and Horn 1 (JO)-   1. 00    5. 00   3.50 _---_- -_   5.06  - _____._
Doll and Hill (ES, 27) _ _ . .   1.00  -_____ -_  -__-_.   2. 00    1. 50    4. so
Hammond (38) __._ -_-__.   1.00 _--__-._  _---__   3. 97   `4.17  __---_._
Kahn (me-. _ ._.__ _-  _ _   1. 00    5. 33    1. 99    4. 05    6. 17  __;e-__-


Sndrwky, ct ul. (77):
  cllscY-*-----.--.~~.~-~--~~~- 104
  Controls __________________.__ 615

Wyndcr, CL cd. (I 13) :
  CUWY~ - - - - __- -- -___--_-___--  30
  Controls _____ _ ___ _ __- _____ __ _  116

Pcrnu (79) :

CRses-.-_------.-...-_-_~--- 202
Controls _____________________ 713

Schwartz, et al. (84) :
  cnsu- --- --__-_--__-________ 249
  Controb __-__________________ 240

Wyndcr nrd Brotls (107) :
cases-..-.--.---..-----.---- 150
  Controb _____________________ 150

Rclativc risk. ___________
Perccn!, cues. _ _ ____ _ __ _
Percent controlj _._____ _.

Rclutivc risk _______ __ ___
Pcrccn t cuscs. _ _ _ _ _ _ . _ _ _
Percent control3 _________

Rclntive risk _____- _ ___ __
Percent crises ___________
Percent controls _________

Rclntive risk ___________.
Perccllt CUSCY _-_____.___
Pcrccnt control3 _________

Rclntivo risk ____________
l'crccnt cnscn- _ _ .______ _
Pcrccnt controb _________

1. 0     4. 8
4      5
13      3

1. 0     3. 1
13      15
24      9

1. 0 _ - _ _ - _ _ _ _
17   _-_______
39   - - - _ - -
    - - _

1. 0  _ _ _ _ - - -
      _ _
2   --___ _-__
18   ___ _- __._

1. 0     3. 0
5      19
15      10

3. 8     5. 1
8      G
7       4

2. 1  _ _ _ _ _ _ - _ _
18 .________
16 -__-____.

3. 0 -. _ _ _ _ _ _ -
7   ___-__-__
5   - _ _ - _ - - - -


2. G - - - - - - - _ -
2   - _ _ - - _ - _ -

9. 0     G. 0
9       4
3       2

3. 8      3. 3
GO       18
53       13


2. 0       . 4
51       3
3G      13

2. 7      5. 0
50       18
50        7

11. 7      8. G
F8       7
67.       7


TABLE 25-Ileldive risk of cancer of the esophagus jor men, comparing cigar, pipe, and cigaretL smokers wiih nonsmokers.
             A summa y of relrospeclive sl dies.--Continued

Author rrf~rence          Number

hllred

Brndshaw and Schonland (1 E) :
  cascs_~--..-_-_~--._---~~--- 117
  Controls _____________________ 366

Martinez (68) :
  Cues...-.---...--.--------- 120
  Controls _____ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _  360

Martinez 1 (69) :
  Cases...-.-----.-.---------- 346
  Controls ____________________ 346

Relative risk ____________     1. 0  _________    4. 8
Percent cases ___________    15   _______-..    41
Percent controls _________    32   _________    18

Relative risk ____________     1. 0     2.0 _____--_
Percent cases ___________    8      9   ------ --
Percent controls _________    14      8   __-_---_

Relative risk ____________     1. 0     2. 0     2. 8
Percent casts ___________    21      10      15
`Percent controls _________    22      9       1

______-_    2. 3 _ _ _ _ - - _ _ _
___-__- _    63   _ _ _ _ _ _ _ _ _
_ _ - _ _ - - -    58   _ _ _ _ _ _ _ _ -

__-mme.-     1. 5      2. 2
i - _
_ _ - - _    31       43
_-_____-    34      34

                 2. 5
- _ _ - -
-   -  -     1. 7
-_----- -    34       34
                25
_ - -
- - -  -  -    36


Lung Cancer

Abundant evidence has accumulated from epidemiologic& expeg-
men-l, and autopsy studies establishing that cigarette smoking is the
major cause of lung cnncer. Several prospective epidemiological
studies have demonstrated higher lung cancer mortality ratios for Pipe
and cigar smokes than for nonsmokerS, but the risk of developing lung
cancer for pipe and cigar smokers is less than for cignrettc smokers
Table 26 presents a summary of these prospective studies. Dose-
response relationships such as those that helped demonstrate the nature
of the ass&ation between cigarette use and Iung cancer could not be
as thororlgldy studied for pipe and cigar smokers because of the rela-
tively few smokers in these categories Although the number of deaths
were few, Doll and Hill (96) reported increased death rates from lung
cancer for pipe and cigar smokers with increasing tobacco consump
tion (table 27). Kahn (50) also demonstrated a dose-response relation-
ship for lung cancer by the amount smoked (table 28).

A few of the retrospective studies contained enough smokers to allow
an examination of dose-response relationships for pipe and cigar smok-
ing and lung canccr (I, 61, 74, 77). An increased risk of developing
lung cancer was demonstrated with the increased use of pipes and
cigars as measured by amount smoked and inhalation. The retrospec-
tive investigation of Abelin and Gsell (I) is of particular interest. The
smoking habits of 118 male patients with cnncer of the lung from a
rural area of Switzerland were compared with those reported in a sur-
vey of all male inhabitants of a town in the same region. About 20
percent of the population of this area were regular cigar smokers, the
most popular cigar being the Stiimpen, a small Swiss-made machine-
manufactured cigar cut at both ends with an average weight of 4.5 g.
In this investigation, cigar smokers experienced a risk of developing
lung cancer that was similar to the risk of cigarette smokers. A dose-
response Elationship was demonstrated for inhalation and amount
smoked. These data suggest that the heavy smoking of certain cigars
may result in a risk of lung cancer that is similar to that experienced
by cigarette smokers.

Several pathologists have reported histologic changes in the
bronchial epithelium in relation to smoking in various forms. Knudt-
aon (57) examined the bronchial mucosa of 150 lungs removed at au-
topsy and correlated the histologic changes noted with the history
of smoking, age, occupation, nnd residence. Specimens obtain& from
the six cigar and pipe smokers demonstrated basal cell hyperplasia;
however, there was no squamous or atypical proliferative metaplasia
as is frequently seen in the heavy cigarette smokers.

Sanderud (78) examined histologic sections from the bronchial tree
of 100 male autopsy cases for the presence of squamous cpithelia]

573


metaplasia. In this study, 39 percent of the population ~vre non-
smokers, 20 percent xvere pipe smokers, and 38 percent smoked cig-
arettes. A total of 80 percent of the pipe smokers and cigarette smokers
demonstrated squamous metaplasia of the bronchial tree, whereas only
54 percent of the nonsmokers had this abnormality.

Auerhach, et al. (6) examined 36,310 histologic sections obtained
from 1,522 white adults for various epithelial lesions including:
presence or absence of ciliated cells, thickness or nurnber of cell rows,
atypical nuclei, and the proportion of cells of various types. The
pathologic findings in the bronchial epithalium of pipe and cigar
smokers are compared to those found in nonsmokers and cigarette
smokers (table 25). Pipe and cigar smokers had abnormalities that
were intermediate between those of nonsmokers and cigarette smokers,
although cigar smokers had pathologic changes that in some categories
approached the changes seen in cigarette smokers.

TABLE 26.-Mortality ratios jor lung cancer deaths in male cigar and
     pipe smokers. A summary of prospectice studies

Author. rererence

Hammond and Horn (do)-   1. 00    3. 35    8.50 ____ -___  23. 12    19.71
Doll and Hill (es, 97) _ _ _ _   1.00 _____---  -_----   6. 14   13.29    7. 43
aest(9)________--_-____   1. 00    2. 94    435 __-_---_  14.91  --__-___
Hammond (S8)-----__ _ __   1. 00    1. 85    2. 24   1. 97    9. 20     7. 39
Kahn (60)--- ___________   1. 00    1. 59    1. a4    1. 67   12. 14  - . ..____

TABLE 27.-Lung cancer death rates for cigar and pipe smokers by amount
             smoked-Doll and Hill

s74


TABLE X-Lung cancer mortality rafiosjor cigar and pipe smokers by
              amount smoked-h'ahn

  <5 pipefuls per day-_ ____ -- _____._______
  5 to 19 pipefuh per day--- _____.__.______
  >I9 pipefuls per day __________________._
Cigar and pipe:

8 or less cigars, 19 or Ievs pipefulj---_-----
>8 cigars, > 19 pipefulz ______._______.___

1. 00           78

1. 14
2. Et
2. 07

.77
2. 20
2. 47

1. 62           18
2. 19            2

12
11
2

2
12
3

&mnx: Kahn. H. A. (50).

575