Document jLoGVyM0BaB5MVe3nyn5BGv9

February 28, 1944* {ffrl L Canada PLAINTIFF'S EXHIBIT V&/>1 Daar Mr. Sabourini X hara your latter of ywiw^fy talcing for comments on -- the relationship between asbestosia and susceptibility to tuberculosis* This question cannot be answered decisively froa a study of post mortem material alone* Medical problems of this nature are usually solved on the basis of probabilities and it is this satter of probabilities on which we need further evidence in the ease of tuberculosis associated with asbestosia* Merewether in his *Meorandum on Asbestosia* Tubercle Movenber and December, 1933 and January, 1934) admits that *the data on the subject are stager** He reports that of 374 workers while at work, only 4 shoved signs of active tuberculosis and that the British Silicosis and Asbestos Medical Board In its first periodie exawlnation of workers in this industry found only one case of asbestosia and tuberculosis in ,1512 examinations. On the other hand the l&gllsh post aorta* material I at that time revaaled 35-TJf of the cases eoxplicated by tuberculosis* 1 (Subsequently he appears to have found wore eases if Dr* Rlddsll Is cor rectly informed)* In the publication cited Merewether concludes! The evidence therefore, points to the hypothesis that at present the added risk to asbestos workers froa p^fli<marr tuberculosis is limited and definitely less than In workers exposed to frss silica; virulent mas sive infections will as in the general population, cause death; lesser ones will result in mors widespread fibrosis then would appear in cases amongst the general population and slight infsetions, in common with many liothsr affectIona, are likely to precipitate death in (leases of advanced asbestosis where they wouldn't do so in the general population.* The underscoring is mine but I agree with these views* When Dr. Merewether was in this country last year he visited me for several days and we spent most of our time discussing these problems* He still accepts our experimental wort which proves that there Is no ! specific susceptibility to tuberculosis induced by asbestosis and he,like ? ourselves, is anxious to accumulate comparative statistics from vfcrlous //parts of the world to establish the general clinical experience*/ <2) As I indicated in my last latter the Quebec experience ia not yet analysed* there is only an impression that most ofjf&e asbestos workers die of tuberculosis without tsktaf Into account the ; excessive prevalence of such infection among the population of'the l Province. This impression needs verification by careful analyst* of mo'rindlty and mortality statistics :ollected from the employees of the asbestos Industry, from their families not exposed to asbestos dust imt from other eououlttas in the Province of Quebec. Such data should than be compared with similar statistics for asbestos workers In other countries. If there is a specific occupational predisposition to tuber* coloala it will become apparent on such analysus just as it has for silicosis. Wherever silicosis is being created, the high mortality from tuberculosis cannot be hidden. I do not believe that there la much tuberculosis / asbestos workers In the United States and suspect that the excess mortality [ from this canse in Vngisnd it probably due to the low living standards j>f industrial workers. Possibly selection of cases'Coming to autopsy "has Influenced the picture* American studies have tteis far failed to demonstrate enough tuberculosis among asbestos workers to cause comment. The U. 6. Public Health Service Study of Asbestosls in the Asbestos Textile Industry In Forth Carolina, (Bulletin 211), issued in 1938, hardly mentioned tuberculosis, dismissing the subject with the statemmkt on page 51 that "there were only 2 cases of active, pulmonary tuberculosis in the group" (511 employees), Shull, (Radiology 27, Vo. 3, 279-292* 193.6) examined 71 of 100 oases discharged from the plants where the Public Health Service made its study 15 months later and found 8 eases complicated by tuberculosis of slight to moderate extant but only 2 were active. These two subsequently died of this cause end In 2 others the infection later became active. Shull states in his conclusions that "asbestosls does not predispose to tuberculosis." Presumably he infers, 'although he does not say so, that the 4 cases of aetive disease among 541 workmen represented accumulated disabilities whan the examination program waa inaugurated. Donnelly (J. 2nd. Hyg. and Teat. 18, Bo. 4, 222-228*1936) also examined 151 discharged employees Installing the 100 reported by Shull* He gives more details on the eases of tuberculosis* One of them had worked In the asbestos industry for 5 months and tike others 15 months. The rams Ini ng 2 had worked 6 and IQ years respectively and their infections might have been aggravated by exposure to asbestos dust. He points eat, however, that an incidence of 2 eases among 151 Industrial employees is no higher than in any other Industrial group. McPheeters, (J. Xnd. Hyg. and Tox., 18, 229-239* 1936) likewise ex amined and reported on these cases and he is in entire agreement with the other reporters. In his conclusions he states,. "Be activating or aggravating effect of asbestos dust or asbestosls or tuberculosis was .observed." Finally I believe Z told you that X ayself, had just re turned from Berth Carolina where I had reviewed cheat films of some 100 employees of the loeal asbestos Industry and saw only one that shoved any Indication of adult type pulmonary tuberculosis. Shis was completely 0705 V Mr* Iran Sabourin (3) Tebruary 28, 1944 haalad. I commented on tha fact to tha members of the Medical Board of tha State Industrial Commission with whoa I was conferring and tha Chairman, Dr* Vestal, told aa that tubarculosls was a rara finding among asbastos workers although common anough in othar industrial vorlcars in thair stata. It would tharefora, appaar that in forth Carolina asbestosis doss not favor or prediapose to tubarculosls. I hart Just now complatad a raviaw of 125 films for an asbastos fabricating plant in anothar stata. In this plant tha amount of severity of tha asbastosls on tha first examination in 1930 was wall marked, approxlnataly 40jf of tha group showing dafinita X-ray avldanea of tha dlssasa. lavarthalass, tha total adult typa tubarculosls rata was only Sit four of thass easas occurred In parsons with asbastosls and 2 of than wars considered probably active. 1 second examination was made upon 67 of tha original group after an interval of 5 years during which they remained at work. Mow the inoidanca of asbastos had increased to 62 but tha tubarculosls rata had fallen to 2.9jf. A third examination was dona on 57 of tha original group who still ramalnad In amploymant after a further interval of 3 to 4 years] in this group tha inoidanca of aabestosla waa over 80Jt but that for tuberculosis only 3.5. In spite of axoeaslva amounts of severe asbastosls the tubarculosls rata remained within tha limits usually found in American industrial populations. Tha behavior of tha tuberculosis in these people waa not unusual, Por example one man, a spinner for 13 years, was 31 years old when first examined. He had at that time an early non-specific dust reaction and evidence of old tubarculosls In tha top of his lungs. In two succeeding examinations his dust reaction steadily Increased to reach first stage asbastosls 9 years after he was first sstn. His tuberculosis however, remained apparently uninfluenced* Moat of the others behaved In the same manner. These people had already bean txposed to asbestos dust for periods of 3 to 18 or more years when they were first examined and the three subsequent examinations during the following 9 years give us a good opportunity to follow what might hava developed, lo new ease of tuberculosis appeared. If it had not by that time the chances were not very great that they would later. After they left the asbestos industry we do not know what happened to most of them but on a few there are Insurance records that Indicate the cause of death. Two died of tuberculosis. One had had his Infection when he waa examined In 1930 at the age of 50* At that time ha had an early aabestosla after weaving for 10 years and evidence of associated chronic tuberculosis. He waa advised to leave which he did and died of his Infection about 3 yaara latar. The second man mged 32 had been a weaver for 12 years and had first stage aabestosla but no evldanoe of tuberculosis at the time, fie left his Job after the 0706 Mr* ITin 8*hourin 4) February 28, 1944 first examination for reasons not stated. Three yaars latsr ha was reported to have dlad of tuberculosis In a sanitoriu*. Such casas could occur anywhere. It Is possible that if ve had follow-ups on more of these eases after they left the asbestos industry we would find aora parsons who subsequently contracted tuberculosis and died of It* However, the erldence now available Indicates no such tendency. Animal texperiments, contrary to those upon silicosis, disclose no theoretical {reasons for suspecting that asbestosis creates any special susceptlI bllity to the tubercle bacillus of Koch. I as becoming aora and more convinced that that the , high tuberculosis rates reported in English autopsy statistics are due / .-to causes other than occupation. I believe that the same must hold ( true in Quebec where the amount of severity of the asbestos dust reaction f'is very much less than It is in the fabricating plants in the United -States. I believe I have covered the other points raised in your letter and will therefore not prolong this discussion further. ery truly yours. Leroy U* Gardner, M. 0. Director LUQsRH oe to Mr. Yandlver Brown CTO 7