Lung Function and Radiographic Disease Worse Among Former Miners in Central Appalachia Than Other Regions of the United States

RATIONALE The COVID-19 pandemic has disrupted national spirometric surveillance of active and former U.S. coal miners since March 2020. Consequently data collected by the Health Resources and Services Administration (HRSA)-funded Black Lung Clinics Program (BLCP) represents the only major source of recent health data on U.S. former coal miners. Using the first available year of national BLCP data we examined associations between mining region and radiographic disease and lung function impairment. METHODS We analyzed pre-bronchodilator spirometry and International Labour Office chest radiograph classifications from miners seen across 15 BLCP grantees from July 1 2020 to June 30 2021. We calculated percent predicted (PP) and lower limits of normal (LLN) for forced expiratory volume in one second (FEV1) forced vital capacity (FVC) and FEV1/FVC ratio. We determined prevalence of patterns of spirometric abnormality (restrictive obstructive/mixed) and moderate to severe impairment (FEV1<70PP). We classified miners who worked the majority of their coal mining career in Kentucky Virginia or West Virginia as Central Appalachian miners. We examined associations between region worked and lung function impairment using logistic regression. RESULTS The 2,891 miners were predominantly non- Hispanic white (98.1%) and male (99.4%) with mean age 66 years (SD9.3). Mean coal mining tenure was 26 years (SD10.7) and 66% (n=1,900) were Central Appalachian miners. Thirty-seven percent had never smoked. Among those with chest radiographs (n=2,464 85%) Central Appalachian miners had a significant three-fold increase in progressive massive fibrosis (PMF) prevalence compared to miners who worked elsewhere in the U.S. (9% vs 3% p<.0001). Smoking history and spirometry were available in 66% (n=1,918). Of these 40% of never-smokers had abnormal spirometry (obstruction/mixed 10%;restriction 30%);among ever-smokers, 54% had abnormal spirometry (obstruction/mixed 27%;restriction 27%). Abnormal FEV1 was present in 30% of never smokers and 42% of ever-smokers. Mean FEV1PP was significantly lower among Central Appalachian miners compared to miners from other regions. Controlling for age, tenure, and pack-years, Central Appalachian miners had significantly elevated odds of having FEV1 impairment compared to non-Central Appalachian miners (OR 1.31, 95%CI 1.06,1.62). A subanalysis controlling for category of radiographic disease showed that odds of impairment remained elevated among Central Appalachian miners (OR 1.24, 95%CI 0.97,1.60). CONCLUSIONS Controlling for smoking, age, and tenure, former miners who worked most of their career in Central Appalachia have significantly increased odds of disabling impairment. These findings highlight the important role of HRSA-funded black lung clinics in understanding work-related lung disease among U.S. coal miners.