Dust content of lungs and its relationships to pathology, radiology and occupational exposure in Ontario hardrock miners

Background Autopsied lungs from 29 hard rock miners were investigated to determine the relationship of the dust content to pathology, radiology, and occupational exposure. Methods Each lung was divided horizontally into three sections. Pathological and radiological studies and chemical analyses were carried out on samples from each section. The hilar lymph nodes were also studied chemically. The work history and smoking history were assessed. The occupational exposure to silica and total dust were estimated. The effect of smoking was examined, and the relationship between dust content of the lungs to that of the lymph nodes were also investigated. Results There was a good agreement between radiologic and pathologic findings. Positive correlations were seen between hydroxyproline (as an index of fibrosis), silica dust, non‐silica inorganic dust, radiographic category of pneumoconiosis and pathologic grade of silicosis. Smokers lost on average 7 years of life compared to non‐smokers, but numbers were small and no adjustment was made. Silica appeared to be concentrated in lungs and lymph nodes compared to the estimates of silica concentration in the mining environment. Silica in the lymph nodes on average is 2.4‐fold higher than in the lungs. Conclusions This study of autopsied hard rock miners lungs shows positive relationships between lung dust and hydroxyproline content, radiological and pathological findings. Am. J. Ind. Med. 51:524–531, 2008. © 2008 Wiley‐Liss, Inc.