Document k6gKk48Nk345b0Er4jOLwQZyB

FILE NAME: Metropolitan Life (ML) DATE: 1944 DOC#: ML212 DOCUMENT DESCRIPTION: Wheatley (Met Life Asst Med Director) Report on Asbestosis and Tuberculosis in Quebec ` TBe7&7*OSIS ASD ASBSSTOSIS A brief review of curreAt knowledge and analysis of tuberculosis mortality in the asbestos mining community of Thetford Mines, P .Q ., Canada Decent developments in Canada have focused attention on the question of the f relationship between asbestosis and tuberculosis. Asbestosis has been declared a compensable disease in the Province of Quebec, 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 end asbestosis 1&2 in the same individuals. In Thetford Mines, 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 I Province of Quebec that there is a causal relationship between tuberculosis and asbestosis similar to the carefully demonstrated and generally accepted relationship between silicosis and tuberculosis. Observations in the United States 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 Lanza^ in 1935 concluded that asbestos dust did not predispose to tuberculosis. In his examination of 126 workers in the.industry in the United States, 53.l wer/*Toun d __ 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 arnL---- ----- found evidence of asbestosis among of the group. No cases, of active tuoa#3rotiT^"""^ wore found among workers with asbestosis. On the other hand, in the group without hsbestoaio he found four active cases of tuberculosis. Two of these active cases' 2 . t*cn in the asbestos industry, six and ten years iNspectively. Donnelly W** c&cludjd that there was no tendency per se in. this type of industrial occupation ' to exacerbate old tuberculosis lesions* HcPbeeters^ reported in 1936 an X-ray survey of 21,0 persons exposed t o asbestos .dust* He found 25*2$ had some evidence of asbestosis. Three cases of active tuberculosis were found. No tuberculosis was found in workers with * * asbestosis* The three individuals with tuberculosis had been exposed 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 10.2 years. McPheeters decided there is no accelerating effect of tuberculosis on asbestosis. I In summation of this evidence it can be said that X-ray and clinical studies .among asbestos workers in the United States does not reveal a significantly greater smount 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 $h 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 19t 6 asbestos workers in the towns of Asbestos and Thetford Mines. The results of this survey appear in Table.1 \ TABLE 1 1 1 tP eixamined Asbestos " 141 % with more than 10 years exposure . 22 Thetford Mines 54 83.4 r* with asbestosis 18 24 % with asbestosis 12.7 44.4 One case 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 indicence in a survey in 1940 of the 7 6 garment tra,de when 1 active case was found per 165 individuals examined. ' Pedley I found that the tuberculosis mortality in Thetford Mines for the years 1926, 1927,and 1928 compared favorably with the tuberculosis mortality for the Province of Quebec, . TABLE 2 ' Average Tuberculosis Mortality for All Ages per 100,000 Place 1926-28 1940-42 % Change Quebec Thetford 123.6 137.9 78.6 252.1 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 has decreased 35% compared to the average rate for. ^he years 1926-28, This corres- > Mines has lied to speculation regarding the influence of asbestos dust Tuberculosis Mortality Study If the industrial exposure to asbestos dust is a significant factor in exacer bating or accelerating* tuberculosis one would expect to find a significant difference in males 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 significant in relation to tuberculosis. Therefore, comparison of the tuberculosis mortality rates in Thetford Mines with communities in the Province of like size, medical and public health facilities, socio-economic and racial characteristics is important. Dublin has pointed economic 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 Through the courtesy of the Demographer of the Provincial Ministry of Health and Social Welfare, Dr. PaullParrot, we were furnished the number of deaths from tuberculosis by age and sex for the years 1939 to 1943 for the cities of Thetford Mines, 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 n^n& principal industry is lumbering and wocd' finishing (see Table 3, p.4&)' v 5 TABLE 4 Shows the Average Mortality Rate by Sex for All Ages in Province and in the Seven Selected Communities 1940-1942 Tuberculosis Death Rate per 100,000 All Ages Male____________ Female PROVINCE OF QUEBEC Cap de la-Madeleine St; Hyacinthe St. John Valleyfield Chicoutimi Thetford Mines Rimouski 77.5 55.9 84.5 75.1 101.7 141.8 190.1 171.9 80.8 44.5 90.9 109.8 85.3 149.1 223.9 287.3 TABLE 3 ^Population Descriptive Industries Date on Selected Communities Health Health Pub.H. ^Private. Officers^ Unit Nurses Physicians Ratio.Phys.to Population... letford Mines 12,000 Asbestos 1 mining Lmouski (incl. 10,000 suburbs) lumbering, wood 1 finishing ip Madeleine 13,000 . rubber mfg., 1 % ' steel foundry, bag, mfg. silk hree Rivers 45,800 paper, linen 1 mfg., rubber, iron hieoutini t. Hyacinthe alleyfield 25,000 aluminum, pulp, 1 paper, iron fdry. clay products / 18,500 textile mfg. 1 . 20,600 munitions, other 1 war industries, cotton, silk 1 . 5 1 4 . 6 12 10 ' 3/1000 2 1/6500 1 9 40 1/115.0 l * * * 10 19 :a/4500 (incl. 7 specs,.) 1 **-**--6 14 1/1300 10 '1/2000 1 ` -5 --^full-time health officers "i: including 1 dentist *" including 1 tb. specialist including 2 full-time physicians M t - 0- Table 4 it will be noted that three of the seven towns for which data btaided have a tuberculosis mortality which is appreciably higher than t h e . provincial rate. Females in Bimouski have the highest average rate for the years . 194042. Females in Thetford Mines have a higher average mortality for the corres ponding period than males in Thetford Mine^ who ranked third in this analysis. Further analysis by age and sex has been attempted for the communities of Rimouski and Thetford Mines and the results appear in Table 5. Interpretation is difficult .because of the ma n number of persons involved in the age. groups in the two communities. It is of interest to note, however, that among Thetford males the highest mortality rate is recorded in males agjkd 25-34. In Rimouski males the highest rate is in the group 35 and older. Thetford females aged `25-34 have the highest rate in either male or female groups, being 519.8 per 100,000, or four times the provincial rate for the same agres. The rate in the corresponding age group 1 in Rimouski females is 446.4 which is nearly three times the Provincial rate in the sams age group. Tuberculosis also takes a high toll in Rimouski females 35 and older. Here the rate is four times that of Provincial females of the same ages. TABLE 5 Tuberculosis Deaths and Death Rates per 100.000 1940-1942 AGE All Ages 0-24 25-34 35 4- .Prov. of Quebec Deaths. Rate 3888 1167 803 1918 77.5. 45.2 102.1 .116.2 MALES Rimouski Deaths Rate .17 5 2 10 f 171.9 93.3 114.4 360.9 Thetford Mines Deaths Rate 36 13 10 23 , 190.1 121.3 342.9 245.0 7 ilCE j All Ages ! 0-24 25-34 35 . Prov. of Quebec Deaths Rate 4019. 1614 1072 1333 80.3 62.7 134.1 83.1 FEMALES Rimouski Deaths Rate 32 ,, ' 13 9 10 287.3 211.9 446*4 334.7 Thetford Mines Deaths Rate 43 '223.9 18 162.5 16 519.5 9 178.1 ENVIRONMENTAL OBSERVATIONS AT THETFORD 0 * Visual inspection of the mills of the three asbestos operators was made Dust counts were made 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 of the population, but this information was reported to us by. competent observers. Several conditions prevail in the mills which would favor the spread of pulmonary tuberculosis. The workmen appear to be careless about spitting and other personal habitB In order to keep warm in cold weather they huddle in groups in small wooden cabin-like enclosures These measure about 6' x 6*. They usually contain a bench or two and a % chair, with some heating facilities] a small tin can on the floor which is used for cigaratte butts, spitting, or left-over food. In one mill a tin drinking cup has been in use for many years. It is obvious that, if there is an employee with tubercle bacilli in his sputum, these environmental conditions favor the spread of tuberculosis It should be noted that in review of the death claims in the mines insured with the _-- -- Company a difference in tuberculosis mortality was found In Mine A between 1941'%S'44y",'`'' eight deaths were due to tuberculosis with a rate of 2.8 per 1,000 employee-years* In Mine B for the corresponding period there were two tuberculosis deaths with a t o of 1.4. It was in Mine A that tbe most conspicuous unsanitary practice, the common * . drinking cup, was found. > Home living conditions gre crowded and it is common practice for children and adults 9 V beds. `This is an important factor favoring the transmission of the disease-- npt ry, because it promotes closer human contact but, by interfering with adequate rest, 'the individual1s 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 i ` the brief time available for inspection and observation. Nevertheless, because of their probable 'importance in creating and maintaining tuberculosis in the community, further investigation of them would seem to be warranted. DISCUSSION It is obvious that tuberculosis mortality is excessive in the town of Thetford Mines. 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-* culosis is also a serious problem in Rimouski 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 tial proportion of the mortality occurring in both sexes under age 24 and the majority of deaths under age 35. There is no evidence, if asbestos dust is a factor, that * it resembles free silica in its influence on tuberculosis mortality. Careful and thorough mortality studies^among granite cutters in the state of Vermont revealed that they are subject to an excessive frequency of deaths from pulmonary tuberculosis, not because of an exceptional risk of contact infection, or because of inferior physique, or because of unfavorable housing conditions or other sanitary deficiencies, but primarily because of the occupational exposure. This same conclusion has been reached in every other study of workers who c6ntract silicosis. Unfortunately we were unable to calculate expected deaths based on the Provincial rates because the age groupings obtained for Thatford Mines and Rimouski did not correspond to the age groupings available in the census data for the Province For further insight into the magnitude of the tuberculosis problem in these two communities, it would be desirable not' only to construct such expectancy tables, but to cariy 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 con to many communities in the Province as well as the Province as a whole, has substantially increased 2 Rimouski, a lumbering town, comparable to Thetford Mines in socio-economic conditions, medical, and public health resources, has a high tuberculosis mortality comparable to Thetford Mines 3 Analysis of the tuberculosis mortality by age and sex in Thetford Mines, in the other communities 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, 4* Admittedly our data is inadequate for final conclusions, nevertheless there is no indication from this mortality study that demonstrates asbestos mining pe 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, Rimouski, and perhaps elsewhere in the Province, 6. Tuberculosis- case-findiiig surveys should be made both in Thetford Mines and comparable communities* TJ" * - 10 - 7. Health education concerning prevention of the disease is needed, as well sb improved sanitation, particularly in the plants* George M. Wheatley, M.D, Assistant Medical Director Metropolitan Life Insurance Company Mr. R, J. Vane,' Manager of Occupation Ratings, has' contributed to this study by valuable suggestions regarding the handling and interpretation of the data as well as hy making the statistical analysis* Dr. A. J. Lartza, Assistant Mdical Director, has very generously permitted us to use his unpublished data secured by Pedley in 1930 on asbestosis and tuberculosis in miners of Thetford and Asbestos* Dr. Lanza has also . advised on the preparation of the final report, % Dr. N. L, Burnette, Assistant. Secretary, secured for us the information on. the socio-economic conditions of the selected communities*