Document 82365oZzDYan9n38bVxaG6dBk

TUBERCULOSIS AND ASBESTOSIS A brief review of current knowledge and analysis of tuberculosis mortality in the asbestos mining community of Thetford Bines, P.Q., Canada Recent developments in Canada have focused attention on the question of the 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 and asbestosis in the same individuals.1'2 In Thetford Bines, 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'1'., 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, 53.1# were found .* i&fedky iy 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 "illa d found evidence of asbestosis among 34*4$ of the group* So cases of active tuberculosis were found among workers with asbestosis. On- the other hand, in tbs group without asbestosis he found four active cases of tuberculosis* Two of these active eases .had been in the asbestos industry six and ten years respectively. Donnelly concluded .. that there was no tendency per se in this type of industrial occupation to xn* old tuberculosis lesions* IdePheeters^ reported in 1936 an X-ray survey of 210 persons exposed to asbestos dust. He found 25*2% some evidence of asbestosis. Three cases of active tuberculosis were found. Ho tuberculosis was found in workers with asbestosis. The three individuals with tuberculosis hnd 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. llcPheeters 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 among 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 There have been no published reports of studies among asbestos workers in 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 Mines.^ The results of survey appear in Table 1. TABLE 1 # examined % with more than 10 years exposure # with asbestoBis % with asbestosis Asbestos 141 22 18 12.7 Thetford Mines 54 83*4 24 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 incidence in & survey in 1940 of the garment trade Whan 1 active case was found per 165 individuals examined.*^ Pedley 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. TABUS 2 Place 1926-23 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 Hines 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 the years 1926-28. This corres ponds to experience elsewhere in Canada and the United States. On the other hand, in Thetford Mines far the corresponding period tuberculosis mortality has increased store than 80^. The obvious existence of a serious tuberculosis problem in Thetford MineB has led to speculation regarding the influence of asbestos dust. Tuberculosis MortenR+nSy 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. Soeio- economic factors are also significant in relation to tuberculosis* Therefore, comparison of the tuberculosis mortality rates in Thetferd Minas with communities in the Province of like size, medical and public health facilities, socio-economic qnri racial characteristics are important* Dublin has pointed out that where socio 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 far the husbands greatly exceeded that of the wives.^ Through the courtesy of the'Demographer of the Provincial Ministry of Health and Social Welfare, Dr. Paxil Parrot, 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, Bimouski, Chicoutimi, Cap da Madeleine, St. Hyacinthe, St. Jean, and Valleyfield, as wall as for the Province and the Dominion as & whole. Of the six communities picked with these characteristics in mind, the town of Bimouski was thought mare nearly to compare with Thetford Mines, except instead of asbestos mining its principal industry is lumbering and wood finishing (see Table 3, p*4a). TABLE 4 Shows the Average Mortality Bate by Sex for All Ages in Province and in the Seven Selected Communities 1940-1942 Tuberculosis Death Bate per 100,000 - All Ages Male Tamale PROVINCE OF QUEBEC Cap de la Madeleine St. Hyacinthe St. John Valleyfield'Chicoutimi Thetford Hines; Bimouski ' 77.5 55*9 34.5 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 'M t t - 4& - TABLE 3 Descriptive Data on Selected Communities Population Industries Health Health Pub.H. # Private Ratio Hays. Officers* Unit Nurses Physicians Pouulation Thetford Mines 12,000 Asbestos mining 1 15 12 3/1000 Eimonslri 10,000 Lumbering, mood 1 finishing 14 10 1A000 Cap Madeleine 13,000 Rubber afg^, 1 steel foundry, bag, mfg. silk 1** 6 2 1/6500 Three Rivers 45,800 Paper, linen mfg., rubber, iron' 1 19 40 1/1150 Chicoutimi 25,000 Aluminum, pulp, 1 paper, iron flicy, clay products lm 30 - 19 1/4500 (Inal. 7 specs.) St. Hyacinths 18,500 Textile mfg* 1 6 14 1/1300 Vallayfield 20,600 Munitions, other 1 mar industries, cotton, silt 15 10 1/2000 full-time health officers Including 1 dentist including 1 tb. specialist including 2 full-time physicians ; ) -5- Prom Table 4 It will be noted that three of the seven tons for which data was obtained have a tuberculosis mortality which is appreciably higher than the Provincial rate. Females in Himouaki have the highest average rate for the years 1940-42. Females in Thetford Hines have a higher average mortality for the corres ponding period than males in Thetford Hines who ranked third in this analysis. Further analysis by age and sex has been attempted for the communities of Blmouski and Thetford Hines and the results appear- in Table 5- Interpretation is difficult because of the 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 aged 25--34* In Blmouski 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*9 per 100,000, or four times the Provincial rate for the same ages. The rate in the corresponding age group in Blmouski females is 446.4 which is nearly three times the Provincial rats in the same age group. Tuberculosis also takes a high toll in Blmouski females 35 and older. Hers the rate is four times that of Provincial females of the same ages* TABUS 5 Tuberculosis De*th sad Death Bates- ner~100rt00 1940-1942 MALES A All Ages 0-24 25-34 354- Prov. of Quebec Deaths Bate 3888 1167 803 1918 77.5 45*2 102.1 116.2 Rlmouskl Deaths Bate 17 171.9 5 93.3 2 114*4 10 360.9 FKMM.W5 Thetford Hines Deaths Bate 36 190.1 13 121.3 10 342.9 13 245*0 Prov. of Quebec MgQflgkj Thetford Mines AGE Deaths Bate Deaths Bate Deaths Bate A11 Ages 1 4019 80.8 32 287.3 43 223.9 0-24 1614 62.7 13 211.9 18 162.5 25-34 1072 134.1 9 446-4 16 519.8 35* \ 1333 83*1 . 10 334.7 9 178.1 4 - 5a EHVTBONMENTAI OBSEBVATIOHS AT THETFCCRD Visual inspection of the mills of the three asbestos operators was made. Dust counts were 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 habits. In order to keep warm in cold weather they huddle in groups in small wooden cabin-like enclosures. These measure about 6* * 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 cigarette 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 1941-1944* eight deaths were due to tuberculosis with a rate of 2*8 per 1,000 employee-years. In Uine B for the corresponding period there were two tuberculosis deaths with a rate of 1.4* It was in Ulna A that the most conspicuous unsanitary practice, the common drinking cup, was found. Home living conditions are crowded and ami it is common practice for children and adults to share beds. This is an important factor favoring the transmission of the disease--not only 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 f 4 - 6- 4 probably 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 torn of Thatford Bines. But there is no indication from these data that occupation is a dominant factor because* 3-) 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 Riaouski where there is no asbestos industry. The age and sex 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 aortal tty. Careful and thorough mortality studies*0 among granite cutters in the State of Vermont revealed vs that they are subject to an excessive frequency of deaths from pulmonary tuberculosis. Jr- not because of an exceptional risk of contact infection, or because of inferior r-S physique, or because of unfavorable housing conditions or other sanitary deficiencies, ~ ' "A but primarily because of the occupational exposure. This same conclusion has been reached 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 Hines and Rimouski did not correspond to the age groupings' available in the census data for tbs Province. Far further insight into the magnitude af_ths tuberculosis problem In these two communities, it vould be desirable not only to construct such expectancy tablesf but to carry out case-finding studies in these and similar communities in the Province - of Quebec. V- V -- 4 -7CONCLUSION 1. Based on current mortality data, tuberculosis in Thetford Nines, in contrast to many communities in the Province as well as the Province as a whole, substantially increased. 2. RiaouaM, a lumbering town, comparable to Thetford Nines in socio-economic conditions, medical and public health resources, has a high tuberculosis mortality comparable to Thetford Nines. 3. Analysis of the tuberculosis mortality by age and sex in Thetford Nines, 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 la 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 per se in Thetford Nines is the cause of the high tuberculosis mortality* Father mortality studies should be made to construct expectancy tables for age and sex in Thetford Nines, Rimouski,-and perhaps elsewhere in the Province. 6. Tuberculosis case-finding surveys should be made both in Thstford Nines and comparable communities. 7. Health education concerning prevention of the disease is needed, ae well as improved sanitation, particularly in the plants. George N. Wheatley, N. D. Assistant Vice-President, Welfare Metropolitan Life Insurance Company Nr. B. J. Vane, Manager of Occupation Eatings, has contributed to study by valuable suggestions regarding the handling and interpretation of the data as well as by waiting the statistical analysis. Dr. A* J. Lanza, Associate Medical Director, has very generously permitted ` us to use his unpublished data secured by Pedley in 1930 on &sbestosia and tuberculosis in miners of Thetford Asbestos. Dr. advised on the preparation of the final report. has ( y r{ >* . Tv. > * ,r J 4 * -8- Dr. N. L. Burnette, Assistant Vice-President, Canadian Head Office, secured for us the information on the socio-economic conditions of the selected communities. REFERENCES 1. Desmeule8, R., Rousseau, L., Giroux, M., and Richard P. "Asbestosis and Pulmonary Tuberculosis". Laval medical. Vol. 8, March 1943* P* 217. 2. DesmeuleB, R., and Giroux, U* "Asbestosis and Pulmonary Tuberudosis*. Laval medical. Vol. 8, March 1943. p 227. 3. Lanza, A. J., McConnell, William J., and Fehnel, J. William. "Effects of the Inhalation of Asbestos Dust on the Longs of Asbestos Workers". Reprint #1665, from the Public Health Reports. Vol. 50, So. 1, January 4, 1935* 4. Donnelly, J. "Pulmonary Asbestosist Incidence and Prognosis". Journal of Industrial Hygiene nd Toxicology. Vol. 18, Ho. 4, April 1936. 5. HcFheeters, S. B. "Survey of a Group of Employees Exposed to Asbestos Dust". Journal of Industrial Hygiene and Toxicology. Vol. 18, Ho. 4, April 1936. 6. Lanza, A. J., and Pedley, Frank G. Unpublished data. 7. Tuberculosis in Industry. Saranac L&baratory Symposium, 1941, Published by the National Tuberculosis Association, p. 199. 8. Pedley, Frank G. "Asbestosis". Canadian Jmirnal of PnVUe palr November 1930. p. 576. 9. Tuberculosis in Industry. Saranac Laboratory Symposium 1941. Published by the National Tuberculosis Association, p. 50. 10. Hoffman, Frederick L. The Problem of Duet phthisis in ftranlte Stone Industry. Bulletin of the U. S. Bureau of Labor Statistics, No. 293, May 1922.