Respiratory symptoms and lung function impairment in underground gold miners in Ghana

Abstract

This is the first study in Ghana in the Obuasi gold mines where the silica content of the respirable dust is 10%, less than in previously studied gold mines, with only 23% of the miners having ever smoked. The study was to assess the prevalence of respiratory impairment in the Ghanaian gold miner and to quantify the effects of the respirable dust on pulmonary function A cross sectional epidemiological study The study was carried out using MRC respiratory symptoms questionnaire, spirometry, and personal respirable dust measurements. A total of 1236 miners were studied. The mean age was 39.7 +/-5.8 (SD) years with a mean of 12.6 +/- 6.7 (SD) years underground service and a mean total cumulative exposure to dust of 10.34 +/-5.61 (SD) mg.m(-3).years. The prevalence of chronic bronchitis was 21.2% and not clearly related to cumulative exposure. MRC breathlessness grade>/=2 was 31.3%, significantly related to cumulative respirable dust exposure after adjustment of age and smoking. There was however significant reduction in FEF(25-75%) with increasing dust exposure and an interaction with ever smoking. There was no correlation between cumulative exposure to respirable dust and FEV(1) % predicted in any group, suggesting that exposure to respirable silica at a mean level of 0.06 mg/m(3) had no deleterious effect on FEV(1) in a population with little tuberculosis, good housing and a low level of cigarette smoking. The prevalence of chronic bronchitis in the Ghanaian gold mine is related more to smoking than any occupational factors.