Archives of Environmental & Occupational Health ISSN: 1933-8244 (Print) 2154-4700 (Online) Journal homepage: https://www.tandfonline.com/loi/vaeh20 Patterns of progressive massive fibrosis on modern coal miner chest radiographs Cara N. Halldin, David J. Blackley, Travis Markle, Robert A. Cohen & A. Scott Laney To cite this article: Cara N. Halldin, David J. Blackley, Travis Markle, Robert A. Cohen & A. Scott Laney (2019): Patterns of progressive massive fibrosis on modern coal miner chest radiographs, Archives of Environmental & Occupational Health, DOI: 10.1080/19338244.2019.1593099 To link to this article: https://doi.org/10.1080/19338244.2019.1593099 Published online: 20 May 2019. Submit your article to this journal Article views: 89 View related articles View Crossmark data AB36-COMM-54-13 Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=vaeh20 ARCHIVES OF ENVIRONMENTAL & OCCUPATIONAL HEALTH https://doi.org/10.1080/19338244.2019.1593099 Patterns of progressive massive fibrosis on modern coal miner chest radiographs a a a a,b a Cara N. Halldin , David J. Blackley , Travis Markle , Robert A. Cohen , and A. Scott Laney a Surveillance Branch, Respiratory Health Division, National Institute for Occupational Safety and Health, Centers for Disease Control b and Prevention, Morgantown, WV, USA; The Division of Environmental and Occupational Health Sciences School of Public Health, University of Illinois at Chicago, Chicago, IL, USA ABSTRACT ARTICLE HISTORY Clinical teaching generally asserts that large opacities of progressive massive fibrosis (PMF) Received 30 July 2018 on chest radiographs present primarily bilaterally in the upper lung zones, and with an ele- Accepted 6 March 2019 vated background profusion of small opacities. However, the contemporary basis for these KEYWORDS descriptions is limited. Epidemiology; occupational Radiographs taken for the Coal Workers’ Health Surveillance Program during 2000–2015 and “ ” n ¼ diseases; occupational previously determined to have large opacities ( PMF radiographs , 204), and a random lung disease sample previously deemed free of large opacities (n =22), were independently reevaluated by three National Institute for Occupational Safety and Health (NIOSH) B Readers. Large opacities were noted primarily in the upper right (41%) or upper left (28%) lung zone, but 31% were in middle or lower zones. Unilateral involvement was observed in 34% of read- ings, with right lung predominance (82%). The median small opacity profusion category for the radiographs with PMF was 2/1. The number of large opacities was not correlated with small opacity profusion category. The “classic” descriptions of PMF as bilateral, associated with elevated background profusions of small pneumoconiotic opacities, were each absent in a third of miners. Introduction publish reports highlighting significant aspects of occu- pational diseases of miners. Coal workers’ pneumoconiosis is a chronic, irreversible Following the establishment of the permissible expos- occupational lung disease caused by the long-term inhal- ure limit in 1969, prevalence of pneumoconiosis among ation of coal mine dust, triggering inflammation of the working underground coal miners declined markedly distal airways, which eventually produces scarring and from 11.7% assessed during 1970–74 to 2.0% assessed irreversible lung damage. Pneumoconiosis can range during 1995–99. However, during the last 15 years from simple to complicated with progressive massive pneumoconiosis prevalence has increased to 4.6% fibrosis (PMF). PMF can be debilitating and fatal. In an among all underground working miners and 12.7% – effort to prevent PMF, the Federal Coal Mine Health among longer tenured miners.2 5 Additionally, PMF, the and Safety Act of 1969 established a federal permissible most severe form of pneumoconiosis, which was nearly exposure limit for respirable dust in underground and eliminated before 1999, has also increased, especially in 1 surface coal mines. The Act also established a surveil- central Appalachia where prevalence has surpassed 5% lance system, the Coal Workers’ Health Surveillance among long-tenured miners.6 These recent findings Program (CWHSP), where actively working miners are have brought renewed attention to the clinical presenta- eligible for periodic chest radiographs to screen for tions and management of coal mine dust lung disease pneumoconiosis. The Act also directs the National among underground and surface coal miners. Institute for Occupational Safety and Health (NIOSH) Chest radiographs are classified for changes consist- to use these data to study the relationships between coal ent with pneumoconiosis according to the mining and occupational diseases, to develop epidemio- International Labour Office (ILO) Classification of logical information about pneumoconiosis and other Radiographs of Pneumoconiosis.7 Parenchymal abnor- mining-related respiratory diseases, and to periodically malities captured by an ILO classification include CONTACT Cara Halldin [email protected] Surveillance Branch, Respiratory Health Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1095 Willowdale Road, Mail Stop HG900.2, Morgantown, WV 26508, USA 2019 Taylor & Francis Group, LLC 2 C. N. HALLDIN ET AL. small and large opacities. Small opacities are fibrotic digitized images were inspected for digitizing artifacts. masses less than 10 mm in diameter and an ILO clas- Personally identifiable information was removed, analog sification captures profusion (or concentration), film radiographs were digitized, and the digital and digi- affected zones of the lung, as well as shape and size of tized images were displayed on dual-screen high-reso- the small opacities. A large opacity is identified when lution physician-quality workstations in a manner the longest dimension of a fibrotic mass exceeds previously described.18 Data from the (M) 2.8 and the 10 mm. PMF is defined as the presence of one or PMF characterization data collection tool were captured more large opacities. Clinical teaching generally asserts digitally in the NIOSH Picture Archiving and that large opacities usually appear bilaterally (though Communications System (PACS) and a database of the some reports suggests that large opacities are more BReaders’ responses was automatically generated. 8 common in the right lung), in the upper lung zones, For each of the large opacities noted on a radio- and often have an asymmetric shape, well-defined graph, Readers were asked to characterize the shape, margins, with a background profusion of major cat- location, and size. Readers were asked to use their egory 2 or 3 small opacities. This conventional know- best judgement in assigning opacities to shape and ledge appears in several respiratory health resources location categories, understanding that only one shape and has been perpetuated in occupational respiratory and one location category could be assigned to each 9,10 11–15 disease articles and medical texts. However, opacity. Opacities which were more than 50% the scientific basis underpinning these descriptions is rounded were considered to be rounded, and opacities limited and appears to rely upon individual examples which were more than 50% asymmetric/polygonal and case reports, many of which are not consistent with shaped were considered to be polygonal. Each large the broad description of upper lung zone involve- 13,16 opacity was assigned to a single lung zone, using the 7 ment. We undertook this study to provide a con- zones defined in the ILO Classification. If an opacity temporary population-based description of PMF in coal overlapped lung zones, the Reader assigned the zone miners, and to establish a baseline which may be useful where the majority of the opacity was located. Readers in monitoring disease patterns over time. Our objective used the PACS display software measuring tool to was to characterize the radiographic presentation of determine the long and short axis in millimeters for large opacities in modern coal miners, by documenting each opacity. Aspect ratio of the opacity was calcu- their number, location (lung zone), size, shape, and the lated (long axis/short axis). Relationships between cat- background profusion of small opacities. egorical variables were evaluated using chi-square test for independence and Pearson’s Correlation Materials and methods Coefficient was used for interval and ratio variables. All radiographs of coal miners who had participated Statistical analysis was completed using SAS 9.4 (Cary, in the CWHSP between 2000 and 2015, and that had NC, USA). This study used existing radiographs, been determined17 to show large opacities, were received a waiver of informed consent, and was selected for the current study, as well as a random approved by the NIOSH Institutional Review Board sample of 22 radiographs which were free of large (15-DRDS-03XP). opacities. Three B Readers, selected at random from the NIOSH CWHSP Reader pool, were asked to par- Results ticipate in this study. Each B Reader independently reevaluated all study radiographs for changes consist- A total of 226 radiographs collected between 2000 and ent with pneumoconiosis, according to the 2015 were identified for evaluation: 204 radiographs International Labour Office (ILO) Classification of had previously been classified as having large opacities Radiographs of Pneumoconiosis7 and recorded their (“PMF radiographs”;