Occupational exposure to respirable crystalline silica and its association with pulmonary function impairment among coal mine workers: A retrospective assessment

Abstract

Occupational exposure to particulate matter in opencast coal mines poses a significant risk to the respiratory health of workers. In this view, the present study primarily involved a retrospective assessment of pulmonary function impairment among coal mine workers using secondary hospital records. In addition, ambient monitoring of suspended particulate matter (SPM), PM10, and respirable crystalline silica (RCS) was conducted at three distinct locations within the studied opencast coal mine to characterize the environmental exposure conditions of the mining area. The health records of 381 coal mine workers were analyzed to examine the interrelationship between pulmonary function and selected socio-demographic and clinical characteristics. The collected data were analyzed using SPSS software, applying both bivariate (Chi-square test) and multivariate (logistic regression) statistical methods. The monitoring campaign at the studied sites revealed mean concentrations of SPM and PM10 of 174.83 and 140.74 mu g/m3, respectively. The mean RCS concentration was 5.59 mu g/ m3 during the study period. These results indicated that although the levels of the analyzed pollutants were within permissible limits, the potential risk of adverse health effects remained substantial, warranting further analysis of medical data from coal workers. Further analyses showed reduced forced vital capacity (FVC) among coal workers, with a calculated reduction of 22.6%. The bivariate analysis showed significant associations among age, weight, BMI, working tenure, and inspiratory and expiratory parameters in mine workers. However, after adjustment in a logistic regression model, work tenure and total cholesterol were the only significant determinants of reduced FVC. Similarly, the prevalence of a forced vital expiration in 1 s (FEV1) decline was 14.2%. It suggested that there is a significant association among age, working tenure, and expiratory parameters, while regression analysis revealed that work tenure and tobacco use were the determinants of decline (FEV1) among coal workers. Overall, the findings of this study provided valuable insights into the occupational health impacts on workers in coal mining environments.