Abstract

BACKGROUND: 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.

OBJECTIVES: 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

DESIGN: A cross sectional epidemiological study

METHOD: The study was carried out using MRC respiratory symptoms questionnaire, spirometry, and personal respirable dust measurements.

RESULTS: 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.

CONCLUSION: The prevalence of chronic bronchitis in the Ghanaian gold mine is related more to smoking than any occupational factors.

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