Radiographic disease progression in contemporary US coal miners with progressive massive fibrosis

Among contemporary US coal miners, there has been an increase in the prevalence and severity of pneumoconiosis, including its advanced form progressive massive fibrosis (PMF). We examine radiographic progression in Coal Workers' Health Surveillance Program (CWHSP) participants.

CWHSP participants with a final determination of PMF during 1 January 2000-1 October 2016 with at least one prior radiograph in the system were included. We characterised demographics, participation and progression patterns.

A total of 192 miners with a PMF determination contributed at least one additional radiograph (total count: 2-10). Mean age at first radiograph was 28.8 years, 162 (84%) worked in Kentucky, Virginia or West Virginia and 169 (88%) worked exclusively underground. A total of 163 (85%) miners had a normal initial radiograph. Mean time from most recent normal radiograph to one with a PMF determination was 20.7 years (range: 1-43) and 27 (17%) progressed to PMF in less than 10 years.

Dust exposure is the sole cause of this disease, and a substantial number of these miners progressed from normal to PMF in less than a decade. Participation in CWHSP is voluntary, and these findings are influenced by participation patterns, so for many miners it remains unclear how rapidly their disease progressed. The National Institute for Occupational Safety and Health recommends all working miners to participate in radiographic surveillance at 5-year intervals. Improved participation could allow more precise characterisation of the burden and characteristics of pneumoconiosis in US coal miners and provide an important early detection tool to prevent cases of severe disease.