Quantitative relation between emphysema and lung mineral content in coalworkers.

Abstract

The relation between quantified emphysema and measured lung content of coal and silica was investigated in the lungs of 264 deceased underground coalworkers who had been exposed to mixed coal and silica dust. Lung specimens obtained at postmortem and inflated and fixed under standard conditions were used to quantify the extent of emphysema and then to measure the amount of coal and silica present in the lungs at the time of death. These data were combined with clinical and other pathological information from the subjects. Multiple regression analysis showed that the extent of emphysema (E score) had a strong positive quantitative relation with coal content of the lungs (p < 0.0003), age (p < 0.0001), and smoking (p < 0.0001). There was a significant negative interaction of uncertain biological importance between coal content of the lungs and smoking (p < 0-004; E score = -1-79 + 0-62 coal + 0-06 age + 0-21 smoking -0-17 coal x smoking; adjusted R' = 0.25). In lifelong non-smokers emphysema was particularly strongly related to coal content and age (coal: p < 0-001; age: p < 0-002; E score = -1-56 + 0-78 coal + 0-06 age; adjusted R2 = 0.66). The relation was basically unchanged by adding a lung silica content term. Emphysema score was highly negatively correlated with forced expiratory volume in one second (FEV1; % predicted, obtained within five years of death) (r = -0-44, p < 0.0001).Degree of lung fibrosis was highly positively associated with lung silica content (X21 = 12-9, p < 0.0003). These results provide strong evidence that emphysema in coalworkers is causally related to lung coal content. The role of silica in development of emphysema, however, remains unclear.

Understanding the Chemical Properties of Macerals and Minerals in Coal and its Potential Application for Occupational Lung Disease Prevention

“…Among the respiratory diseases, CWP received the most attention because of its clear occupational association. Asthma, emphysema, and chronic bronchitis in coal workers show a significant positive correlation with (a) the number of years worked at the coal mine independent of age at death; and (b) the severity of pneumoconiosis (Leigh et al, 1983(Leigh et al, , 1994. While mining exposures contribute significantly to lung disease, smoking is an important factor in the development of lung cancer and COPD, thus necessitating a comprehensive approach for prevention and control of mining-related occupational lung disease Ross & Murray, 2004).…”

Increased mortality in COPD among construction workers exposed to inorganic dust

“…The reported declines were y7-8 mL?yr -1 , after adjustment for age and smoking. Studies of coal miners have shown an increased mortality due to bronchitis and emphysema [11][12][13], especially centrilobular emphysema [14][15][16]. A relationship between dust exposure and degree of emphysema has been found in studies of coal and hard-rock miners [17,18].…”

Interaction of Iron and Calcium Minerals in Coals and their Roles in Coal Dust-Induced Health and Environmental Problems

“…Among the respiratory diseases, CWP has received the most attention because of its clear occupational association. Asthma, emphysema, and chronic bronchitis in coal workers have a signifi cant positive correlation with (a) the number of years worked at the coal mine independent of age at death; and (b) the severity of pneumoconiosis (Leigh et al 1983(Leigh et al , 1994. While mining exposures contribute signifi cantly to lung disease, smoking is a major factor in the development of lung cancer and COPD, thus necessitating a comprehensive approach for prevention and control of miningrelated occupational lung disease Ross and Murray 2004).…”