{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,16]],"date-time":"2026-09-16T04:15:26Z","timestamp":1789532126098,"version":"build-2803163510"},"reference-count":26,"publisher":"BMJ","issue":"7","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Occup Environ Med"],"published-print":{"date-parts":[[1998,7]]},"abstract":"<jats:p>OBJECTIVES: To investigate the following questions. (1) Is silica dust on its own, without the presence of silicosis, associated with an increased risk of pulmonary tuberculosis (PTB) in workers exposed to silica dust? (2) In the absence of silicosis is the excess risk dose related? (3) What is the predominant chronological sequence between the development of PTB and the development of silicosis after the end of exposure to dust? METHODS: A cohort of 2255 white South African gold miners has been followed up from 1968 to 1971, when they were 45-55 years of age, to 31 December 1995 for the incidence of PTB. During the follow up 1592 (71%) men died. Of these, 1296 (81%) had a necropsy done at the National Centre for Occupational Health (NCOH) to determine the presence of silicosis and PTB. The incidence of PTB in the cohort was studied relative to cumulative exposure to dust and the onset of silicosis. For the miners with necropsy, the incidence for PTB was studied relative to the severity of silicosis found at necropsy. RESULTS: There were 115 subjects who developed PTB. The total person-years of follow up was 39,319. For the whole cohort, the factors associated with increased risk of PTB were cumulative exposure to dust (mg\/m3.y) (the adjusted rate ratio (RR) 1.07; (95% confidence interval (95% CI) 1.04 to 1.10)), silicosis diagnosed radiologically (3.96 (2.59 to 6.06)), and tobacco pack-years (1.02 (1.01 to 1.03)). The RR (95% CI) for PTB increased with increasing quartiles of cumulative exposure to dust 1.0, 1.51 (0.78 to 2.91), 2.35 (1.28 to 4.32), and 3.22 (1.75 to 5.90). In miners who did not have radiologically diagnosed silicosis (n = 1934, PTB = 74), the adjusted RR (95% CI) for PTB and cumulative exposure to dust was 1.10 (1.06 to 1.13), and increased with quartiles of cumulative exposure to dust as 1.00, 1.46 (0.70 to 3.03), 2.67 (1.37 to 5.23), and 4.01 (2.04 to 7.88). For the subjects who had a necropsy (n = 1296, PTB = 70), the adjusted RR (95% CI) for PTB increased with the severity of silicosis found at necropsy; 1.0 for no silicosis, 1.88 (0.97 to 3.64) for negligible, 2.69 (1.35 to 5.37) for slight, and 2.30 (1.16 to 4.58) for moderate or marked silicosis. For subjects who had a necropsy and no silicosis (n = 577, PTB = 18), the adjusted RR (95% CI) increased slightly with quartiles of cumulative dust 1.0, 1.11 (0.31 to 4.00), 1.42 (0.43 to 4.72), and 1.38 (0.33 to 5.62). CONCLUSION: Exposure to silica dust is a risk factor for the development of PTB in the absence of silicosis, even after exposure to silica dust ends. The risk of PTB increases with the presence of silicosis, and in miners without radiological silicosis, with quartiles of exposure to dust. The severity of silicosis diagnosed at necropsy was associated with increasing risk of PTB and even &lt; 5 nodules--that is, undetectable radiologically--was associated with an increased risk of PTB. The diagnosis of PTB was on average 7.6 years after the end of exposure to dust, at around 60 years of age. The onset of radiological silicosis preceded the diagnosis of PTB in 90.2% of the cases with PTB who had silicosis. The results have implications for medical surveillance of workers exposed to silica dust after the end of exposure.<\/jats:p>","DOI":"10.1136\/oem.55.7.496","type":"journal-article","created":{"date-parts":[[2008,12,31]],"date-time":"2008-12-31T19:13:30Z","timestamp":1230750810000},"page":"496-502","source":"Crossref","is-referenced-by-count":179,"title":["Risk of pulmonary tuberculosis relative to silicosis and exposure to silica dust in South African gold miners."],"prefix":"10.1136","volume":"55","author":[{"given":"E","family":"Hnizdo","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"J","family":"Murray","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[1998,7,1]]},"reference":[{"key":"ref_1","first-page":"455","article-title":"Relationship between tuberculosis and silicosis","volume":"118","author":"Snider, D.E.","year":"1978","unstructured":"Snider DE. Relationship between tuberculosis and silicosis [editorial]. Am Rev Respir Dis 1978;118:455\u201360.","journal-title":"Am Rev Respir Dis"},{"key":"ref_2","author":"Watkins-Pitchford, W.; Moir, J.","year":"1916","unstructured":"Watkins-Pitchford W, Moir J. Report No. 8. Johannesburg: South African Institute for Medical Research, 1916."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1460","DOI":"10.1164\/ajrccm.150.5.7952577","article-title":"The epidemiology of tuberculosis in gold miners with silicosis","volume":"150","author":"Cowie, R.L.","year":"1994","unstructured":"Cowie RL. The epidemiology of tuberculosis in gold miners with silicosis. Am J Respir Crit Care Med 1994;150:1460\u20132.","journal-title":"Am J Respir Crit Care Med"},{"key":"ref_4","first-page":"677","article-title":"Mortality of middle aged South African gold miners","volume":"43","author":"Wyndham, C.H.; Bezuidenhout, B.N.; Greenacre, M.J.","year":"1986","unstructured":"Wyndham CH, Bezuidenhout BN, Greenacre MJ, et al. Mortality of middle aged South African gold miners. Br J Ind Med 1986;43:677\u201384.","journal-title":"Br J Ind Med"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1136\/oem.53.1.11","article-title":"Mortality of South African gold miners","volume":"53","author":"Reid, P.J.; Sluis-Cremer, G.K.","year":"1996","unstructured":"Reid PJ, Sluis-Cremer GK. Mortality of South African gold miners. Occup Environ Med 1996;53:11\u201316.","journal-title":"Occup Environ Med"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"217","DOI":"10.1002\/ajim.4700270207","article-title":"Mortality study of gold miners exposed to silica and non-asbestiform amphibole minerals: an update with 14 more years of follow up","volume":"27","author":"Steenland, K.; Brown, D.","year":"1995","unstructured":"Steenland K, Brown D. Mortality study of gold miners exposed to silica and non-asbestiform amphibole minerals: an update with 14 more years of follow up. Am J Ind Med 1995;27:217\u201329.","journal-title":"Am J Ind Med"},{"key":"ref_7","first-page":"110","article-title":"Morbidity of pulmonary tuberculosis among silicotic and non-silicotic foundry workers in Denmark","volume":"32","author":"Sherson, D.; Lander, F.","year":"1990","unstructured":"Sherson D, Lander F. Morbidity of pulmonary tuberculosis among silicotic and non-silicotic foundry workers in Denmark. J Occup Med 1990;32:110\u20133.","journal-title":"J Occup Med"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"339","DOI":"10.1016\/S0013-9351(86)80195-5","article-title":"Silicosis and risk of lung cancer or tuberculosis: a cohort study","volume":"41","author":"Westerholm, P.; Ahlmark, A.; Maasing, R.","year":"1986","unstructured":"Westerholm P, Ahlmark A, Maasing R, et al. Silicosis and risk of lung cancer or tuberculosis: a cohort study. Environ Res 1986;41:339\u201350.","journal-title":"Environ Res"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"374","DOI":"10.1016\/0007-0971(80)90072-8","article-title":"Active pulmonary tuberculosis discovered at post-mortem examination of the lungs of black miners","volume":"74","author":"Sluis-Cremer, G.K.","year":"1980","unstructured":"Sluis-Cremer GK. Active pulmonary tuberculosis discovered at post-mortem examination of the lungs of black miners. Br J Dis Chest 1980;74:374\u20138.","journal-title":"Br J Dis Chest"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"706","DOI":"10.1164\/ajrccm.153.2.8564121","article-title":"Occupational disease trends in black South African gold miners","volume":"153","author":"Murray, J.; Kielkowski, D.; Reid, P.","year":"1996","unstructured":"Murray J, Kielkowski D, Reid P. Occupational disease trends in black South African gold miners. Am J Respir Crit Care Med 1996;153:706\u201310.","journal-title":"Am J Respir Crit Care Med"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"636","DOI":"10.1136\/oem.54.9.636","article-title":"Variation in incidence of tuberculosis in subroups of South African gold miners","volume":"54","author":"Kleinschmidt, I.; Churchyard, G.","year":"1997","unstructured":"Kleinschmidt I, Churchyard G. Variation in incidence of tuberculosis in subroups of South African gold miners. Occup Environ Med 1997;54:636\u201341.","journal-title":"Occup Environ Med"},{"key":"ref_12","article-title":"Tuberculosis mortality and silica dust exposure: a case-control study based on a national mortality database for the years 1983\u2013","author":"Chen, G.X.; Burnett, C.A.; Cameron, L.L.","unstructured":"Chen GX, Burnett CA, Cameron LL, et al. Tuberculosis mortality and silica dust exposure: a case-control study based on a national mortality database for the years 1983\u2013"},{"key":"ref_13","first-page":"163","article-title":"Occup Environ","volume":"3","author":"Int, J.","year":"1997","unstructured":"Int J Occup Environ Health 1997;3:163\u201370.","journal-title":"Health"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"148","DOI":"10.1002\/(SICI)1097-0274(199608)30:2<148::AID-AJIM5>3.0.CO;2-X","article-title":"Occupational risk factors for developing tuberculosis","volume":"30","author":"Rosenman, K.D.; Hall, N.","year":"1996","unstructured":"Rosenman KD, Hall N. Occupational risk factors for developing tuberculosis. Am J Ind Med 1996;30:148\u201354.","journal-title":"Am J Ind Med"},{"key":"ref_15","first-page":"465","article-title":"Potentiation by silica of the growth of Mycobacterium tuberculosis in macrophage cultures","volume":"49","author":"Allison, A.C.; Hart, D.\u2019Arcy; P.","year":"1968","unstructured":"Allison AC, D\u2019Arcy Hart P. Potentiation by silica of the growth of Mycobacterium tuberculosis in macrophage cultures. Br J Exp Pathol. 1968;49:465.","journal-title":"Br J Exp Pathol"},{"issue":"83","key":"ref_16","first-page":"510","volume":"1961","author":"Gross, P.; Westrick, M.L.; McNerney, J.M.","unstructured":"Gross P, Westrick ML, McNerney JM. Experimental tuberculosis. Am Rev Respir Dis 1961;83:510.","journal-title":"Experimental tuberculosis. Am Rev Respir Dis"},{"key":"ref_17","first-page":"253","article-title":"Immunological aspects of silicosis","volume-title":"silica-induced lung diseases","author":"Iyer, R.; Holian, A.","year":"1996","unstructured":"Iyer R, Holian A. Immunological aspects of silicosis. In: Castranova V, Wallyathan V, Wallace E, eds. Silica and silica-induced lung diseases. Boca Raton: CRC Press, 1996:253\u2013267."},{"key":"ref_18","first-page":"114","article-title":"Silica exposure and tuberculosis: An old problem with some new twists","volume":"32","author":"Balmes, J.","year":"1990","unstructured":"Balmes J. Silica exposure and tuberculosis: An old problem with some new twists. J Occup Med 1990;32:114\u2013115.","journal-title":"J Occup Med"},{"key":"ref_19","article-title":"Gold Fields West Hospital Annual Medical Report, 1995","year":"1995","unstructured":"Gold Fields West Hospital Annual Medical Report, 1995. Johannesburg: Gold Fields West, 1995."},{"key":"ref_20","first-page":"727","article-title":"Chronic obstructive lung disease in gold miners","volume-title":"particles IV, part 2","author":"Wiles, F.J.; Faure, M.H.","year":"1977","unstructured":"Wiles FJ, Faure MH. Chronic obstructive lung disease in gold miners. In: Walton WH, ed. Inhaled particles IV, part 2. Oxford: Pergamon Press, 1977:727\u201335."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"447","DOI":"10.1002\/ajim.4700240409","article-title":"Risk of silicosis in a cohort of white South African gold miners","volume":"24","author":"Hnizdo, E.; Sluis-Cremer, G.K.","year":"1993","unstructured":"Hnizdo E, Sluis-Cremer GK. Risk of silicosis in a cohort of white South African gold miners. Am J Ind Med 1993;24:447\u201357.","journal-title":"Am J Ind Med"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"427","DOI":"10.1002\/ajim.4700240408","article-title":"Correlation between radiological and pathological diagnosis of silicosis: an autopsy poulation based study","volume":"24","author":"Hnizdo, E.; Murray, J.; Sluis-Cremer, G.K.","year":"1993","unstructured":"Hnizdo E, Murray J, Sluis-Cremer GK, et al. Correlation between radiological and pathological diagnosis of silicosis: an autopsy poulation based study. Am J Ind Med 1993;24: 427\u201345.","journal-title":"Am J Ind Med"},{"key":"ref_23","first-page":"10","article-title":"A study of the dust exposure of South African white gold miners","volume":"73","author":"Page-Shipp, R.J.; Harris, E.","year":"1972","unstructured":"Page-Shipp RJ, Harris E. A study of the dust exposure of South African white gold miners J S Afr Inst Mining Metallurgy 1972;73:10\u201324.","journal-title":"J S Afr Inst Mining Metallurgy"},{"key":"ref_24","article-title":"SAS\/STAT User\u2019s Guide","author":"SAS Institute","year":"1988","unstructured":"SAS Institute. SAS\/STAT User\u2019s Guide. Cary, NC: SAS Institute, 1988."},{"key":"ref_25","first-page":"1820","article-title":"Silico-tuberculose en Suisse, Schweiz Med Wochenschr","volume":"100","author":"Barras, G.","year":"1970","unstructured":"Barras G. Silico-tuberculose en Suisse, Schweiz Med Wochenschr 1970;100:1820."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"761","DOI":"10.1164\/ajrccm.155.2.9032226","article-title":"American Thoracic Society. Adverse eVects of crystalline silica exposure","volume":"155","year":"1997","unstructured":"American Thoracic Society. Adverse eVects of crystalline silica exposure. 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