Drillers and mill operators in an open-pit gold mine are at risk for impaired lung function

BACKGROUND: Occupational studies of associations of exposures with impaired lung function in mining settings are built on exposure assessment and far less often on workplace approach, so the aim of this study was to identify vulnerable occupational groups for early lung function reduction in a cohort of healthy young miners. METHODS: Data from annual screening lung function tests in gold mining company in Kyrgyzstan were linked to occupations. We compared per cent predicted forced expiratory volume in one second (FEV(1)), forced vital capacity (FVC) and FEV(1)/FVC between occupational groups and tested selected occupations in multivariate regression adjusted for smoking and work duration for the following outcomes: FEV(1) < 80 %, FEV(1)/FVC < 70 % and both. RESULTS: 1550 tests of permanent workers of 41 occupations (mean age 40.5 ± 9.2 years, 29.8 % never smokers) were included in the analysis. The mean overall VC was 103.0 ± 12.9 %; FVC 109.1 ± 13.0 % and FEV(1) 100.2 ± 25.9 %. Drillers and smoking food handlers had the lowest FEV(1)%. In non-smokers, the lowest FEV(1) was in drillers (94.9 ± 11.3 % compared to 115.2 ± 17.7 % in engineers). Drillers (adjusted odds ratio (OR) 1.53 (95 % confidence interval (CI) 1.11-2.09)) and mill operators (OR 2.01 (1.13-3.57)) were at greater risk of obstructive ventilation pattern (FEV(1)/FVC < 70 %). CONCLUSIONS: Drilling and mill operations are the highest risk jobs in an open-pit mine for reduced lung function. Occupational medical clinic at site should follow-up workers in these occupations with depth and strongly recommend smoking cessation.