Emphysema and lung mineral content in coalworkers

Publisher Summary This chapter discusses the lung coal content in coal workers and its relation to the development of emphysema. A non-smoking miner with the average lung coal content would have emphysema involving an extra 7 to 10% of the whole lung mass compared to a non-smoking person of the same age who was not exposed to coal. The influence of coal is less marked in smokers due to a negative interaction between smoking and coal. The very high R 2 term in the regression equation for non-smokers shows that coal exposure and age are the main determinants of emphysema in non-smoking coalworkers. Processes like dust trapped in the increased mucus produced in bronchitis alter the proportion of total lung dust in the parenchyma, affecting the relationship between total lung dust and emphysema. Another reason for the coal-emphysema association is that emphysema somehow impairs clearance of dust from the lungs. Greater emphysema therefore is associated with dust in the lung because of decreased clearance rather than because the dust causes the emphysema.