This study was done to determine the degree of co-morbidity of silicosis and pulmonary tuberculosis in ex-mineworkers, measure distribution of the conditions in different age groups and to determine the length of service in the mines in relation to the disease states.
Between 28th May 1997 and 27th May 1999, 2080 former mineworkers were examined at the “Benefit Examination Clinic” in the Pulmonology unit of Umtata General Hospital (UGH). The mining history of each attendee was recorded and an identification form completed. The form was either signed or fingerprinted by the miner. After physical examination, a chest radiograph was taken. The radiographs were sent to an independent radiologist, experienced in Occupational Lung Diseases, for assessment. These were rated according to International Labor organization (ILO) guidelines.
The age of those studied ranged from 35 to 70 years (mean 51.6 years) and their length of service in the mines ranged from 1 to 48 years. On radiological examination 5.5% showed only silicosis and 28.4% had silicosis with pulmonary tuberculosis (Relative risk=5.08, χ2 = 27.3, p<0.01). Among subjects up to 35 years 9.1% had mild, 10.6% marked, and 1.5% severe silicosis. A probable diagnosis was made on 9.1% of the cases. The least number of afflicted was seen in the 36 to 45 year age group (21.2%). Surprisingly, most number of cases were in those 35 years or less (30.3%). About half (48.4%) the silicotic subjects had worked in the mines between 11 to 20 years.
Pulmonary TB is 5- times higher in silicotic than in non-silicotic subjects.
These findings will help clinicians, epidemiologists, compensation authorities and policy makers in understanding of the silicosis problem in this region of South Africa.
Banwari Lal Meel, None.