Coal Dust Exposure Linked to Emphysema Severity

New research from the National Institute for Occupational Safety and Health (NIOSH) indicates that exposure to coal dust is directly linked to the severity of emphysema in smokers and nonsmokers alike. These findings highlight a health problem related to a growing number of individuals, as coal production has nearly doubled worldwide in the past 25 years.

Researchers at NIOSH compared lung autopsy results from 722 individuals, including 616 coal miners and 106 non-miners from West Virginia and Vermont between 1957 and 1978. Exposure to coal dust was estimated using work history data and job-specific dust exposure estimates. Sections of the lungs were then examined to determine the presence and extent of emphysema, which was graded for type and severity.  Lung tissue from a smaller subset of the study group was also analyzed for dust content.

Researchers found that cumulative exposure to respirable coal mine dust to be a significant predictor of emphysema severity. Cigarette smoking, age at death and race were all accounted for separately, and emphysema in miners was found to be significantly more severe than non-miners in both smokers and non-smokers.  However, emphysema was also more severe among smokers than non-smokers in miners and non-miners, demonstrating that cigarette smoking and dust exposure have similar effects on emphysema severity.

It was also found that higher concentrations of coal dust in the lungs negatively affected the severity of emphysema.

Researchers caution that the data was collected from individuals who worked in the mines before enforcement of the federal standard limiting legal coal dust concentrations in 1972. This removes any immediate relevance to current occupational safety standards.

Nonetheless, researchers believe that, even at the current federal standard, a working lifetime of exposure to coal dust will produce a cumulative exposure similar to the levels found in the autopsied miners. Coal dust exposure is now generally accepted as a cause of COPD, but this study will improve the recognition of dust-induced COPD, its relationship to cigarette smoking, and could enhance prevention efforts, diagnosis and medical management of occupational dust-related lung diseases. Click here to read the full story on ScienceDaily.