Prevalence and pathogenesis of pneumoconiosis in coal workers.

Abstract

Dust dose and composition do not appear to account wholly for changes in the prevalence of coal workers' pneumoconiosis in Europe. In certain coal pits high progression evidently occurred with relatively low dust exposure or vice versa, whereas progression in relation to dust levels might be variable. Exceptionally high quartz concentrations occur in coal mine dust when pneumoconiosis may progress with unusual rapidity. Under such circumstances lesions resembling silicotic nodules may be found, but with the customarily lower levels of quartz the pathological features assume the form characteristic of coal workers. Morphological changes in relation to dust content of human and animal lungs, as well as cellular behavior, have not accounted completely for the epidemiological findings. Considering all the pathological evidence helps explain the pathogenesis of pneumoconiosis and vagaries of progression. The origin of progressive massive fibrosis cannot be explained simply in terms of dust burden or immunological features, and the role of an infective factor cannot be dismissed. Moreover, lipid secretion by alveolar epithelium introduces a new element that could affect the development of simple and complicated pneumoconiosis. In vitro, cytotoxicity appeared to be too variable for predictive purposes, though direct assay of fibrogenicity using the macrophage fibrogenic factor suggested that dust dose was more important than dust composition. Assessing individual susceptibility presents serious obstacles.

Silicosis and coal workers' pneumoconiosis.

“…They studied the pathologic changes in the lungs of coal trimmers exposed to coal that was free of silica and showed that workers developed pneumoconiosis despite low silica exposure. Gough et al (46) and Heppleston (47,48) confirmed these findings and showed that the histologic pulmonary lesions in coal trimmers were identical to those found in underground coal miners. CWP is now clinically and pathologically distinguished from silicosis.…”

Prevalence Characteristics and Prediction of Coal Workers' Pneumoconiosis in the Tiefa Colliery in China

“…Some researches showed that the CWP prevalence declined markedly, highlighting feasibility and effectiveness of dust control in coal mines 15,17,18) . It is consistent with results from observed a series of respiratory symptoms relating to the CWP and concurrent epidemiological investigations 19) .…”

Airways obstruction, coal mining, and disability.

“…This was shown by Gough and Heppleston many years ago,'7 18 and has subsequently been confirmed by the US Public Health Service studies which showed that simple CWP in nonsmokers was associated with an increase in the residual volume and total lung capacity and in some instances with a slight to moderate loss of elastic recoil. '920 Furthermore, Hankinson and colleagues, who were working in the Appalachian Laboratory for Occupational Lung Disease (ALFORD) at the same time showed that simple CWP was associated with an increase in air space size.2' These workers were, however, unable to demonstrate that the increased size was associated with a reduction in ventilatory capacity.…”