Document DD1xo2EEoYOdKdVapBOvrYk95
decent developments in Canada have focused attention on the question of the
relationship between asbestosla and tuberculosis* Asbestosis has been declared a
compensable disease in the Province of Q&ebac, thus increasing medico-legal interest
in. the establishment of this diagnosis and evaluation of any contributing factors* '
Autopsy of asbestos miners has disclosed evidence of active tuberculosis and asbestosis
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in the sane individuals*
In Thetford Hines, where a substantial part of all the .
asbestos in Canada is produced, the mortality from tuberculosis has in the past 16
years approximately doubled in contrast to a significant decline in the Provincial
rate. These developments have materially helped to create the impression in the Province of Quebec that there is a causal relationship between tuberculosis and asbestosis similar to the carefully demonstrated and generally accepted relationship
tween silicosis and tuberculosis*
Observations in the United States
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Previous studies of workers exposed to asbestos dust have not disclosed a higher
incidence of tuberculosis among workers with clinical and X-ray evidence of asbestosis*
tansa^ in 1935 concluded that asbestos dust did not predispose to tuberculosis* la
his examination of 126 workers in the. industry in the United States, 53l wore found
to have definite X-ray evidence of asbestosis* Two cases of active tuberculosis were
found* One of these was a worker with asbestosis*
.
In 1936^ Donnelly reviewed X-ray film of 151 workers in asbestos mills and
found evidence of asbestosis among 3Al of the group* No cases, of active tuberculosis
were found among workers with asbestosis* On the other hand, in the group without s'bestoais he found four active cases of tuberculosis* Two of these active cases' ,
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pxd been in the asbestos industry, six and ten Tears respectively. Donnelly
concluded that there was no tendency per se in this type of industrial occupation *
to exacerbate old tuberculosis lesions,
''
HcPheetera^ reported in 1936 an X-ray survey of 22,0 person* exposed to
'.
asbestos dust. He found 25.25 had some evidence of asbestos!** Three cases
of adtive tuberculosis were found. Ho tuberculosis was found in workers with
asbestosis. The three individuals with tuberculosis had been expoaed to asbestos *
dust 6, 9, and 10 years respectively. In five cases healed pulmonary tuberculosis
and asbestosis were found in association. The average duration of* exposure for
the 5 was 10.4 years and for the entire group 1C.2 years, HcFheeters decided `
there is no accelerating effect of tuberculosis on asbestosis.
In summation of this evidence it can be said that X-ray and clinical studies
.^mcng asbestos workers in the United States does not reveal a significantly greater
amount of tuberculosis than expected In the routine examination of workers in any
industry, Moreover there is no evidence from these studies to indicate that long
exposure to asbestos dust activates or accelerates the tuberculous process. Both
these observations are In contrast to findings among workers exposed to free silica*
Canadian Observations
These have been no published reports of studies among asbestos workers fa Canada
with respect to the prevalence of asbestosis or of tuberculosis in the asbestos
industry,' In 1930 Pedley and his associates examined physically and by X-ray 195 asbestos workers In the towns of Asbestos and Thetford Hines. 6 The results of this
survey appear in Table.1,
'
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TABLE 1
Asbestos
Thetford H
rf* examined
% with more than 10 years e^osurt .
141 22 .
54 63.4
r? with asbestosis
' 13
24
% with asbestosis
12*7
44*4
One c&se of active tuberculosis was found among the 195 individuals examined*
This is a very satisfactory Incidence of tuberculosis among an Industrial group,
even today* For example, it approximates the indlcence in a survey in 1940 of the
garment trade when 1 active case was found per 165 individuals examined* ` Pedley
found, that the tuberculosis mortality in Thetford Mines for the years 1926, 1927,and 1^ compared favorably with the tuberculosis mortality tor the Province of Quebec* .
TABLE 2
'
Average Tuberculosis Mortality for All Ages per 100,000
Place
1926-23 1940-42
% Change
Quebec Thetford
123.6 137.9
73.6 252.1
35 83 +
However, since this report of Pedley there has been a sharp change in the tuberculosis mortality relationship between Thetford Mines and the Province as a whole. Table 2 shows that in the Province of Quebec the average rate for the three years 1940-42 . b iecreaeed 352 compared to the average rate for. Se years 1926-23* This corres- '
nds to experience elsewhere in Canal* and the United States, On the other hand, in Thetford Mines for the corresponding period tuberculosis mortality has Increased'
re than 8C5S, The obvious existence of a serious tuberculosis problem in Thetford Mines has led to speculation regarding the influence of asbestos dust.
Tuberculosis Mortality Study - If the industrial exposure to asbestos dust is a significant factor in exacer--
bsting or accelerating tuberculosis one would expect to find a significant difference
in sales over 25 years of age since, in Thetford Mines, practically all of this part of the population not in military service work in'the asbestos industry, Socio
economic factors are also signifleant in relation to tuberculosis. Therefore, comparison of the tuberculosis mortality rates in Thetford Mines with commanitles in the Province of like size, medical and public health facilities, socio-economic
and racial characteristics is important, Dublin has pointed
socio-
inomlc factors were dominant the tuberculosis mortality rates for both husbands and wives were similarly affected; where industrial factors played a leading role the standardized mortality rates for the husbands greatly exceeded that of the wives,^
Through the courtesy of the Demographer of the Provincial Ministry of Health *
and Social Welfare, Dr, PauliParrot, we were furnished the number of deaths from
tuberculosis by age and sex for the years 1939 to 1943 for the cities of Thetford
Hines, Rimouski, Chicoutimi, Cap de Madeleine, St, Hyacinthe, St, Jeand, and
Valleyfield, as well as for the Province and the Dominion'as a whole. Of the six
communities picked with these characteristics in mind, the town of Rimouski was thought more nearly to compare with Thetford Mines, except instead of asbestos
serving its principal industry is lumbering and wocd finishing (see Table 3, p#4*)\
TABLE 4
Shows the Average Mortality Hate by Sex for All Ages is Province and in the Seven Selected C omnitie3
. 1940-1942
*
Tuberculosis Death Bata per 100,000
All Ages
Male
Tftffala
PB07IKCS OF QUEBEC Cap de la Madeleine
St. Hyacinths
St. John Valleyfield Chicoutimi Thetford Mines Bimouaki
77.5 55.9 34.5 75.1 101.7 141.3 190.1
171.9
80.8
44.5 90.9 109 .8
85.3 149a 223.9 287.3
TABLE 3
Descriptive Date on Selected Cossunitles
c
Population Industries
Health
Health Pub.H. Private. Eatio: Pbys
Officers Unit Nurses Physicians Populatioi
itford Mines 12,000
Asbestos mining
1
icuski (inol.. 10,000 iuburbs)
lumbering, wood finishing
1
3 Madeleine 13,000
%
rubber afg., 1 steel foundry,
bag, ofg silk
1
ee Elvers
45,S00
paper, linen rnfg., rubber, iron
1
c outini
25,000
aluminum, pulp, 1
paper, iron fdry., clay products
Hyacinthe :e- * 'eld
18,500 20,600
textile mfg.
munitions, other war industries, cotton, silk
1 1
1.
5
14 X'* 6
12
10 * 2
l/icoo l/lOCO 1/65CO
1 : 9 40 1/H50 .
10 19 43/4500 (inel 7 specs.)
1 *** * * _ 1 -5
14 1/1300 10 _ '1/2000
'all-tins health officers deluding 1 dentist
/.-v including 1 tb. specialist
rentable 4 It will be noted that three of the seven towns for which data \
^ -roshnei have a tuberculosis mortality which is appreciably higher than the .
--*--J rate. Females in Rimouski have the highest average rate for the years .
resales in Thetford Mines have a higher average mortality for the corres-
pried than males in Thetford Kines who ranked third in this analysis*
.
Purccer analysis by age and sex has been attempted Tor the communities of
.
sa; Thetford Mines and the results appear in Table 5. Interpretation is
`
difficult because of the small number of persons involved in the age.' group* in the
two cc==uties. It is of interest to note, however, that
Thetford males
*
the higher mortality rate is recorded in males ag^ed 25-34. In Rlmouski males
the higheit rate is in the group 35 and older. Thetford females aged *25-34 have
the bittern. rate in either male or female groups, being 519.3 per 100,000, or four
times the Provincial rate for the same agree. The rate in tbs corresponding age group
in Rimma sd. females is 446.4 which Is nearly three times the Provincial rate in the
C- ase sroup. Tuberculosis also takes a: high toll in
females 35 aai older.
Here tme ate is four times that of Provincial females of the same ages.
TABLE 5
'
Tuberculosis Deaths and Death Rates per 100.000 1940-1942
.
* KALES
All 0-24 25-335-*
Prov. of Cusbee Deaths late
3323 116?
303 1913
77.5. 45.2
102.1 116.2
Riaouski
Deaths
Rate
.17 171.9 5 93.3 2 114.4
10 360.9
.
' *
Thetford Mines Deaths Rate
33
13 10
13 ,
190.1
121.3 342.9 245.0
-7-
.
A1 w
All Ages 0-24 25*34 35 ^
Prov. oX Quebec
Deaths
Bate
4019. 1614 1072 1333
80,3
62.7 134.1
83.1
7&KALZ5
p
Biraouski
Deaths
Bate
32 287.3
13 211.9 9 446.4
10 334.7
'
ThetXord Mines . Deaths Bate
43 223.9 18 162.5 16 519.3
9 178.1
.
mXBOBKSmL OBSERVATIONS AT THETPOHD
*.
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Visual inspection oX the sills of the three asbestos operators was Bade, Dust -
counts were Bade at all important working locations of these properties, and the
.
results are given in a separate report. There was no opportunity to personally observe
home conditions, eating and living habits oX the population, but this information was
reported to us by. coapetent observers.
Several conditions prevail in the mills which would Xavor the spread oX pulmonary
` berculosis. The workmen appear to be careless about spitting and other personal habiti
In order to keep warm in cold weather they huddle in groups in
wooden cabin-libi
enclosures. These measure about 6* i 6r, They usually contain a bench or two and a
chair, with some heating Xacilitiesj a small tin can on the Xloor which is used Xor
cigarette butts, spitting, or leXt-over Xood, In one mill a tin drinking cup has been
in use Xor many years. It is obvious that, IX there is an'employee with tubercle
'
bacilli in his sputum, these environmental conditions Xavor the spread of tuberculosis*
It should be noted that in review oX the death claims in the mines insured with the
Company a difference in tuberculosis mortality was found. In Mine A between 1941*1944.,
eight deaths were due to tuberculosis with a rate oX 2,3 per 1,000 employee-years* In
Mine B Xor the corresponding period there were two tuberculosis deaths with a rate oX
1,4, It was in Mine A that the most conspicuous unsanitary practice, the common
nking cup, was Xound,
_
Homs living conditions gre crowded
it is common practice Xor children and adult
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share bods* 'This is an important factor favoring the transmission of the disease--apt on-*1''- because it promotes closer human contact but, by interfering with adequate rest, the individual's resistance to infection is lowered* Poor eating habits and food selection which prevail also contribute to the lowering of resistance to tuberculosis*
. These observations on environmental factors are admittedly superficial because of the brief tine available for inspection and observation* Nevertheless, because of their probable' importance in creating and maintaining tuberculosis in tbs cccsmmity, further investigation of then would seen to be warranted*
DISCUSSION It is obvious that tuberculosis mortality is excessive In the town of Thetford Hines* But there is no indication from these data that occupation is a dominant factor because; l) the mortality is equally bad among females; 2) it is excessive in the age group under 24 where there is little or no industrial exposure; 3) tuber*
r
cuTw s is also a serious problem in Riaouski where there is no asbestos industry. The age and sax distribution of mortality from tuberculosis resembles the
Picture of tuberculosis in a heavily seeded, susceptible population with a substan* .iai proportion of the mortality occurring in both sexes under age 24 and the majority if deaths under age 35* There is no evidence, if asbestos dust is a factor, that t resembles free silica in its influence on tuberculosis mortality* Careful and horough mortality studies^among granite cutters in the state of Vermont revealed
cat they are subject to an excessive frequency of deaths from pulmonary tuberculosis,
ct because of an exceptional risk of contact infection, or because of inferior
lysique, or because of unfavorable housing conditions or other sanitary deficiencies*
it primarily because of-the occupational exposure* This same conclusion has been
ac*d in every other study of workers who contract silicosis*
Unfortunately we were unable to calculate expected deaths based on the Provincial
rates because the age groupings obtained for Thetford Mines and Rlaouski did not
j'rrespond to the age groupings available in the census data for the Province, For
further insight into the magnitude of the tuberculosis problem in these tvo
communities, it would be desirable not* only to construct such expectancy tables,
but to cany out case-finding studies in these and similar communities in the Province
of Quebec*
. ' *. . *
CONCLUSION
-
1* Based on current mortality data, tuberculosis in Thetford Mines, in contrast
to sany communities in the Province as well as the Province as a whole, has
.
substantially increased*
2, Riaouski, a lumbering town, comparable to Thetford Mines In socio-economic
conditions, medical and public health resources, has a high tuberculosis mortality
C sparable to Thetford Mines*
'
_
. 3 Analysis of the tuberculosis mortality by age and sex in Thetford Hines,
in the other ccramities and in the Province shows that both males and females in
Thetford succumb to the disease with approximately the same frequency* This is not
the mortality picture seen where there is industrial exposure to free silica,
1* Admittedly our data is inadequate for final conclusions, nevertheless there
is no indication from this mortality study that demonstrates asbestos ninlag per se
in Thetford Mines is the cause of the high tuberculosis mortality^
5* Further mortality studies should be made to construct expectancy tables for'
age and sex in Thetford Mines, Rinouski, and perhaps elsewhere in the Province*'
6, Tuberculosis- case-finding surveys should be made both in Thetford Hines and
comparable communities
10 -
Health education concerning prevention of the disease is needed, as well as
proved sanitation, particularly In the plants*
George K* Wheatley, HD, Assistant Medical Director Metropolitan Life Insurance Ccnpan
Hr. E. J. Vane, Manager of Occupation Eatings, has contributed to this
study by valuable suggestions regarding the handling and Interpretation
of'the data as well as by leaking the statistical analysis*
' 1.
. '
Dr* A. J* Lancs, Assistant Medical Director, has very generously permitted
us to use his unpublished data secured by Pedley in 1930 on asbestosls and
tuberculosis in ainers of Tbetford and Asbestos* Dr. Laos* has also
advised on the preparation of the final'report.
-#
-
.
Dr. N. L. Burnette, Assistant Secretary, secured for us the information on - . the socio-econosic conditions of the selected consaunities*
11 -
REFERENCES
1. Desmeules, R., Rousseau, L., Giroux, M., and Richard P, "Asbestos!* and ` Pulmonary Tuberculosis". Laval medical. Vol. 8, March, 1943. p.217.
2. Desnsules,E,, and Giroux, K. "Asbestos!* and Pulmonary Tuberculosis*. Laval medical. Vol. 3, March 1943. p. 227.
'
3. Lanza, A. J., McConnell, William J, and Fehnel, J. William. "Effects of the
Inhalation of Asbestos Dust on the Lungs of Asbestos Workers." Reprint 1665,
from the Public Health Reports, Vol. 50, No, 1, January 4, 1935.
'
4. Donnelly, J, "Pulmonary Asbestosis; Incidence and Prognosis". Journal of ..
Industrial Hygiene and Toxicology, Vol, 18, No. 4, April 1936,
.
5. McPheeters, S. B, "Survey of a Group of Employees Exposed to Asbestos Dust". Journal of Industrial Hygiene and Toxicology, Vol. IS, No. 4, April 1936.
6. Lanza, A. J,, and Pedley, Prank G. Unpublished data,
-*
7* Tuberculosis in Industry, Saranac Laboratory Symposium, 1941. Published by the National Tuberculosis Association, p, 199.
S, Pedley, Frank G. "Asbestosis*. Canadian Journal of Public Health. November 1930.
9 Tuberculosis in Industry. Saranac Laboratory Symposium, 1941. Published by
(
the National Tuberculosis Association. p,50.
10 Hoffman, Frederick L. The Problem of Dust Phthisis in the Granite Stone Industry.
' Bulletin of the U. S. Bureau of Labor Statistics, No. 293, Hay 1922.
.
.r /
A. . - /*>
da
IVAN SABOURIN, Q.C.
16
ALORCO UIUO(M9r MONTMSAU.
MEMO
This Taberculosis-A sbestosta 1044 Surrey conducted by Metropolitan Lite (Dr, George Wheatley then Assistant Medical Director of Metropolitan Life in Kw York) might be of interest to you. At the time thie study was communicated to the officers at Quebec such as Workmen's Compensation Board, departmental heads and also to the members of the Pneumoconiosis Committee of the Workmen's Compensation Board and also to the then pulmonary experts in the Province,
The attached copy' was made out of the basic report of Dr, Wheatley which I have in my files.
In connection with Cancer, the same prejudice is rampant now, as you know, which was rampant before 1944 as to Tuberculosis, The Metropolitan surrey dispelled that prejudice. At that time we also had test cases conducted (the hearings being attended by the leading experts of the continent) to prove that asbestosls exposure did not invite ?,&,
As to Cancer - exposure to asbestos incidence, the Pittsburg survey took place in the 50*s<Dr, Daniel Brana - his study vas also published) which survey's conclusions, just as in the case of asbestosls, coacioded that there is not seemingly any relationship between dost exposure and cancer.
Dr, Braun (together with Dr, Grdgoire, Professor Beattie of Cambridge, Professor Knahner of New York University -- an expert in the pathology of cancer tumors --_ is a member of the scientific v committee of our proposed Institute under the chairmanship of Dr. `Wright,
April 29th, 19M.
I.S.
1VAX SABOX7H1N ,4-C.
ADVOCATE
CitcULd
"P`Q'
/
Montreal.
MEMO
This Tuberculosis-Asbestosis 1944 Survey conducted by
Metropolitan Life (Dr. George Wheatley then .Assistant Medical Director of Metropolitan Life in New York) might be of interest to you. At the time this study was communicated to the officers at Quebec such as Workmen's Compensation Board, departmental heads and also to the members of the Pneumoconiosis Committee of the Workmen's Compensation Board and also to the then pulmonary experts in the Province.
The attached copy was made out of the basic report of
Dr. Wheatley which I have in my files.
.
In connection with Cancer, the same prejudice is rampant
now, as you know, which was rampant before 1944 as to Tuberculosis,
The Metropolitan survey dispelled that prejudice.
At that time
we also had test cases conducted (the hearings being attended by the
leading experts of the continent) to prove that asbestosis exposure
did not invite T.B.
As to Cancer * exposure to asbestos incidence, the Pittsburg survey took place in the 50's (Dr. Daniel Braun - his study was also published) which survey's conclusions, just as in the case of asbestosis, concluded that there is not seemingly any Relationship between dust exposure and cancer.
Dr. Braun (together with Dr. Grdgoire, Professor Beattie of Cambridge, Professor Kushner of New York University -- an expert in the pathalogy of cancer tumors --) is a member of the
scientific committee of our proposed institute under the chairmanship of Dr. Wright.
April 29th, 1966.
I.S.
>* *
"i<r
'?*
16
JOURNAL OF INDUSTRIAL HYGIENE AND' TOXICOLOGY
[so/. 28, no. L
dust that a worker may breathe over a period of among these workers would have been considerably
years. It Is further apparent that to obtain such greater. In view of the varied character of the
a picture, daily dust counts at each specific job environmental dust exposure in the pipe covering
in each ship compartment and in the shop together industry on naval vessels, it is manifestly impossible
with the time spent on each job would have to to set a threshold., ,
be compiled separately for each worker. In this respect, asbestos pipe covering differs markedly'
. VI. CONCLUSIONS
'.
from the asbestos textile industry where dust
1. The character of asbestos pipe' covering
concentrations for an operation do not fluctuate industry on board naval vessels is such that'
widely and where a worker will usually remain at conclusions drawn from other asbestos industries-
a specific job for some years.
such as textiles, cannot be applied.
.. .
A further factor in maintaining a low incidence 2. The Operations ofband saw cutting, grinding,
of asbestos;* is that in band saw cutting, grinding, cement mixing, and installation .on board ship
and cement mixing only one or two men are in should be equipped with exhaust .ventilation to
volved and the work is usually done at infrequent keep the total dust concentration low.
..
intervals such as several times a week.
3. The incidence of asbestosis among pipe-
Finally, pipe coverers also apply glass wool, covcrers in' the shipyards studied was low, 0.29 per
rock wool, magnesia, and other types of non cent or 3 cases out of 1074. In view of the n&tarc
asbestos insulation, all of which deceases the -of shipyard pipe covering work, this low incidence
amount of exposure to asbestos dust.v It seems is not surprising.
::
likely to us that if the pipe coverers studied had 4. Since each of the 3 cases of asbestosis had
worked steadily at any of the above operations worked at asbestos pipe covering in shipyards iot
where the amount of asbestos dust in the air was more than 20 years, it may be concluded that such
consistently high, the incidence of asbestosis pipe covering is not a dangerous occupation.
REFERENCES
(1) Lanza, A. J.: Silicosis and asbestosis, ' Oxford.
University Press, New York, New York, 1938.
(2) Dassssxx, W. C. et aL: A study of asbestosis
in the asbestos textile industry. BulL No.
241, Public Health Service, U. S. Treasury,
Department, 1938.
(3} Fahxy, J. C.; Ships^and aircraft of the United States Fleet. 2nd War Edition, 1944. Pub* lished by Ships and Aircraft, 1265 Broadway, New York, New Yoek.-
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