OCCUPATIONAL-DISEASE TRENDS IN BLACK SOUTH-AFRICAN GOLD MINERS - AN AUTOPSY-BASED STUDY

The change in prevalence in silicosis and pulmonary tuberculosis in bl ack South African gold miners dying from unnatural causes from 1975 to 1991 was studied. Data were analyzed for 16,454 black gold miners. In formation on age at death, duration of service, year of autopsy examin ation, and the prevalence of silicosis and tuberculosis was collected. Analyses were done to assess secular trends in the prevalence of tube rculosis and silicosis, and to determine predictors of the diseases at death. The prevalence of tuberculosis increased from 0.9% in 1975 to 3.9% in 1991. The prevalence of silicosis increased from 9.3% to 12.8% . The prevalence of both diseases increased with age and duration of s ervice. Silicosis was the most significant predictor of tuberculosis ( odds ratio [OR] = 1.78, confidence limits [CL] = 1.27 to 2.30). A sign ificant trend for tuberculosis, for year of autopsy, remained after ad justment for the other variables in the model, such as age and duratio n of service (p = 0.0046). In view of current labor stabilization in t he South African mines, one can expect further increases in the preval ence of tuberculosis and silicosis. Lowering of dust levels in the min es is urgently required to prevent the increase of disease burden.