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Original research
Progression of coal workers’ pneumoconiosis absent further exposure
  1. Kirsten S Almberg1,
  2. Lee S Friedman1,
  3. Cecile S Rose2,
  4. Leonard H T Go1,
  5. Robert A Cohen1
  1. 1 School of Public Health, Division of Environmental and Occupational Health Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
  2. 2 Department of Medicine, National Jewish Health, Denver, Colorado, USA
  1. Correspondence to Dr Kirsten S Almberg, School of Public Health, Division of Environmental and Occupational Health Sciences, University of Illinois at Chicago, Chicago, Illinois 60612, USA; almberg{at}


Objectives The natural history of coal workers’ pneumoconiosis (CWP) after cessation of exposure remains poorly understood.

Methods We characterised the development of and progression to radiographic progressive massive fibrosis (PMF) among former US coal miners who applied for US federal benefits at least two times between 1 January 2000 and 31 December 2013. International Labour Office classifications of chest radiographs (CXRs) were used to determine initial and subsequent disease severity. Multivariable logistic regression models were used to identify major predictors of disease progression.

Results A total of 3351 former miners applying for benefits without evidence of PMF at the time of their initial evaluation had subsequent CXRs. On average, these miners were 59.7 years of age and had 22 years of coal mine employment. At the time of their first CXR, 46.7% of miners had evidence of simple CWP. At the time of their last CXR, 111 miners (3.3%) had radiographic evidence of PMF. Nearly half of all miners who progressed to PMF did so in 5 years or less. Main predictors of progression included younger age and severity of simple CWP at the time of initial CXR.

Conclusions This study provides further evidence that radiographic CWP may develop and/or progress absent further exposure, even among miners with no evidence of radiographic pneumoconiosis after leaving the industry. Former miners should undergo regular medical surveillance because of the risk for disease progression.

  • progressive massive fibrosis
  • coal workers’ pneumoconiosis
  • progression
  • chest radiographs
  • black lung benefits

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  • Contributors KSA contributed to concept design and data acquisition and was principally responsible for data analysis and manuscript preparation. KSA takes primary responsibility for the integrity of the work as a whole. LSF, CSR, LHTG and RAC contributed to concept design, data acquisition, analysis, interpretation and manuscript revision.

  • Funding This research was supported by funding from the Alpha Foundation for the Improvement of Mining Safety and Health, Inc, grant #: AFC113-4. The views, opinions and recommendations addressed herein are solely those of the authors and do not imply any endorsement by the Alpha Foundation, its Directors and staff.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval This study was approved by the University of Illinois Chicago Institutional Review Board, #2013–1114.

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

  • Data availability statement No data are available. The data used in this manuscript is not available for public use. This analysis was performed on a de-identified data set from the US Department of Labor and was provided to the study authors pursuant a Memorandum of Understanding between the US Department of Labor and the University of Illinois at Chicago.