DALLAS — U.S. coal miner mortality from progressive massive fibrosis, a lethal form of black lung disease, has made a significant resurgence in recent years; however, a cause has yet to be determined, according to researchers.
Additionally, black lung, nonmalignant respiratory diseases and COPD appear to account for a greater proportion of death in the younger generation of miners, according to Kirsten Almberg, PhD, of the Environmental and Occupational Health Sciences School of Public Health, and colleagues.
Presented at the American Thoracic Society International Conference, two adjacent studies analyzed miner mortality patterns as well as the rise of progressive massive fibrosis (PMF) in recent years.
“Coal miners suffer excess mortality from nonmalignant respiratory diseases, including pneumoconioses and COPD,” the authors of one study wrote. “The U.S. Department of Labor collects data on coal miners applying for Federal Black Lung Program benefits. Mortality data from this population has never been analyzed before and would be the largest study to date of cause of death in U.S. coal miners.”
Recent reports have pointed toward a mysterious increase in the occurrence of PMF, most likely attributed to excess exposure to respirable crystalline silica.
Analyzing PMF data from the 1971-2012 National Coal Workers’ Autopsy Study performed by the National Institute for Occupational Safety and Health (NIOSH), Robert Cohen, MD, FCCP, of the Environmental and Occupational Health Sciences School of Public Health, and colleagues sought to find a historical shift in PMF caused by classic coal mine dust to that caused by silica.
According to the study results, researchers identified 150 coal-type PMF cases, 120 mixed-type and 106 silicotic-type PMF from coal miners born between 1885 and 1942. There was a significant increase in the proportion of silicotic PMF occurring after 1990 vs. before 1990 (40% vs. 24%; P = .002), the authors noted.
In the adjacent study of coal miner mortality patterns, researchers used data from the National Death Index of individuals who filed for Federal Black Lung Program benefits and participated in the NIOSH Coal Workers’ Health Surveillance Program, from 1970 to 2016. This amounted to a study population that included 34,771 deceased coal miners.
Researchers noted that the proportional mortality from nonmalignant respiratory diseases was 28% in individuals born between 1930 and 1939 and increased to 32% for individuals born between 1940 and 1970. A similar trend was observed in proportional mortality from COPD.
Mortality from nonmalignant respiratory disease, specifically pneumoconiosis, also increased among coal miners younger than 65 years in the most recent cohort compared with earlier birth cohorts.
Additionally, mortality from lung cancer was found to be at 19% for coal miners born after 1940. This is a significant increase compared with the miners of the same age from the previous birth cohort who saw 7% to 11% proportional mortality from lung cancer.
“This increase is pronounced among younger miners and may reflect increased mortality from progressive massive fibrosis, which is occurring more frequently and in younger U.S. coal miners,” the authors wrote. “The increased proportional mortality from lung cancer in the most recent birth cohort may reflect exposure to workplace carcinogens (eg, diesel exhaust, respirable silica) for which further analysis is planned.” – by Scott Buzby
Almberg KS, et al. Abstract 2759.
Cohen RA, et al. Abstract 2758. Both presented at: American Thoracic Society International Conference; May 17-22, 2019; Dallas.
These studies were supported by NIOSH and the Alpha Foundation for the Improvement of Mining Safety and Health. The authors report no relevant financial dislcosures.