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Original research
Measuring lung diffusing capacity: an opportunity for improved medical surveillance and disability evaluation of coal miners
  1. Leonard H T Go1,2,
  2. Kirsten S Almberg1,
  3. Lee S Friedman1,
  4. Lauren Zell-Baran3,
  5. Cecile S Rose3,
  6. Robert A Cohen1,2
  1. 1 Environmental and Occupational Health Sciences Division, University of Illinois Chicago, Chicago, Illinois, USA
  2. 2 Pulmonary and Critical Care Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
  3. 3 Division of Environmental and Occupational Health Sciences, National Jewish Health, Denver, Colorado, USA
  1. Correspondence to Dr Leonard H T Go, School of Public Health, University of Illinois Chicago, Chicago, IL 60612, USA; lgo2{at}uic.edu

Abstract

Objectives Spirometry is the primary lung function test utilised for medical surveillance and disability examination for coal mine dust lung disease. However, spirometry likely underestimates physiologic impairment. We sought to characterise abnormalities of single-breath diffusing capacity for carbon monoxide (DLCO) among a population of former coal miners.

Methods Data from 3115 former coal miners evaluated at a West Virginia black lung clinic between 2006 and 2015 were retrospectively analysed to study the association between diffusion impairment (abnormally low DLCO), resting spirometry and the presence and severity of coal workers’ pneumoconiosis on chest radiography. We developed ordinary least squares linear regression models to evaluate factors associated with per cent predicted DLCO (DLCOpp).

Results Diffusion impairment was identified in 20.2% of subjects. Ten per cent of all miners with normal spirometry had diffusion impairment including 7.4% of never smokers. The prevalence of diffusion impairment increased with worsening radiographic category of pneumoconiosis. Mean DLCOpp decreased with increasing small opacity profusion subcategory in miners without progressive massive fibrosis. Linear regression analysis also showed significant decreases in DLCOpp with increasing small opacity profusion and presence of large opacities.

Conclusions Diffusion impairment is common among former coal miners, including among never smokers, miners without radiographic pneumoconiosis and miners with normal spirometry. These findings demonstrate the value of including DLCO testing in disability examinations of former coal miners and an important role for its use in medical surveillance of working miners to detect early chronic lung disease.

  • Occupational Health
  • Physiology
  • Coal Mining
  • Respiratory Function Tests
  • Respiratory System

Data availability statement

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Footnotes

  • LHTG and KSA are joint first authors.

  • Contributors LHTG and KSA led the analysis. LHTG, KSA, LSF, LZ-B, CSR and RAC contributed to the conduct of the research. LHTG wrote the first draft of the manuscript. LHTG, KSA, LSF, LZ-B, CSR and RAC contributed to the editing of the manuscript. LHTG and KSA are the guarantors of the study.

  • Funding This research was supported by grant AFCTG-20-102 from the Alpha Foundation for the Improvement of Mining Safety and Health, Inc.

  • Disclaimer The findings and conclusions of this report are those of the authors and do not necessarily represent the official position of the Alpha Foundation for the Improvement of Mine Safety and Health, Inc.

  • Competing interests LHTG and RAC report preparing independent medical reviews for individuals with occupational lung disease.

  • Provenance and peer review Not commissioned; externally peer-reviewed.

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