The objective of this report was to study the early effects of coal dust on lung function in new underground coal miners. Two hundred and eighty-seven male minen were selected from new employees at the Xuzhou Mining Group Company as study group, and 132 male students at a mining technical school were selected as conttol. Data collection included: individual demographic parameters, family medical history, occupational history, smoking history, measurement of dust concentrations in work areas, and lung function tests. This prospective cohort study took place over 3 years during which time total dust and respirable dust concentrations in the new coal miners' work areas were measured twice.each month. For both miner and student groups, FVC and FEV1 were tested initially, before dust exposure, and then 15 times over the 3 years. The average total dust and respirable dust concentrations in the miners' work areas were 23. 8 mg/m3 and 8.9 mg/m3 respectively, which greatly exceeded national health criteria. During the first year of dust exposure, the miners' average FVC was higher than that of the controls ( 5.19 L vs 4.92 L, P < 0.01). During the second and third years, the difference in average FVC between the miners and the control group was not significant (5.14 L vs 5.12 L, P > 0.05). Before dust exposure, the miners' FEV1 was significantly higher than that of the control group (4,48 L vs 4.28 L). In the miners' group, FEV1 declined rapidly during the first year following dust exposure (from 4.48 L to 4.25 L) ,and in the second and third years, the average FEV1 of the miners was.significantly lower than that of control group (4.34 L vs 4.56 L, P < 0 . 01 ), although there were some fluctuations during the follow-up period. Overall, the average FEV1 of the miners' group showed a significant decline during the study. There were significant correlations between FVC or FEV1 and age, height,, weight, and smoking. The three-year total loss of FVC and FEV1 in smoking miners (154 ml,184 ml) were greater than in non-smoking miners (83 ml, 91 ml). There are apparent effects of coal dust on lung function in new underground coal miners, with FEV1 being more impacted than FVC. Smoking may aggravate the effect of dust exposure on reducing lung function.
Department of Occupational Health and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province 430030, China