Occupational Safety and Health of Women in Mining

The mining industry plays a critical role in the U.S. economy, with active mines in every state producing materials such as those used to construct houses and roads, make medicines, and manufacture cars and electronics. Throughout its history, mining has been a male-dominated industry. Recent estimates indicate that between 10% and 17% of miners are women. Previous occupational safety and health (OSH) research has focused primarily on the male experience. In more recent years, the mining industry has engaged in efforts to increase workforce diversity through the recruitment and retention of women miners. To meet the needs of a diverse workforce, it is critically important to identify OSH concerns that are unique to populations that have been understudied and to develop work-related policies and practices that improve their work experiences and health outcomes. The purpose of this article is to describe the specific OSH challenges women as miners face and to discuss how the National Institute for Occupational Safety and Health's (NIOSH) Mining Program is situated to address these challenges through its Mining Program Strategic Plan.

Increased odds of mortality from non-malignant respiratory disease and lung cancer are highest among US coal miners born after 1939

OBJECTIVES

Coal miners suffer increased mortality from non-malignant respiratory diseases (NMRD), including pneumoconioses and chronic obstructive pulmonary disease, compared with the US population. We characterised mortality trends from NMRD, lung cancer and ischaemic heart disease (IHD) using data from the Federal Black Lung Program, National Coal Workers' Health Surveillance Program and the National Death Index.

METHODS

We compared mortality ORs (MORs) for NMRD, lung cancer and IHD in former US coal miners to US white males. MORs were computed for the study period 1979-2017 by birth cohort (<1920, 1920-1929, 1930-1939, ≥1940), with a subanalysis restricted to Central Appalachia.

RESULTS

The study population totalled 235 550 deceased miners, aged >45 years. Odds of death from NMRD and lung cancer across all miner birth cohorts averaged twice those of US males. In Central Appalachia, MORs significantly increased across birth cohorts. There was an eightfold increase in odds of death from NMRD among miners born after 1940 (MORBC≥1940 8.25; 95% CI 7.67 to 8.87). Miners with progressive massive fibrosis (PMF) were younger at death than those without PMF (74 vs 78 years; p<0.0001). We observed a pattern of reduced MORs from IHD in coal miners compared with national and regional counterparts.

CONCLUSION

US coal miners have excess mortality from NMRD and lung cancer compared with total US and Appalachian populations. Mortality is highest in the most recent birth cohorts, perhaps reflecting increased rates of severe pneumoconiosis.

Postexposure progression of pneumoconiosis among former Appalachian coal miners

BACKGROUND

The prevalence of pneumoconiosis among working United States underground coal miners has been increasing for the past two decades, with the highest rates of disease observed among miners in the central Appalachian states of Kentucky, Virginia, and West Virginia. Surveillance for this disease in the United States focuses on working coal miners, who continue to be occupationally exposed to dust. This study examines the radiographic evidence for postexposure progression of pneumoconiosis in a population of former coal miners no longer occupationally exposed to coal mine dust who were seen at a community radiology clinic in eastern Kentucky.

METHODS

Data were obtained and analyzed from clinical records of former coal miners who had a clinic encounter during January 1, 2017-August 1, 2019, a recorded final year of employment, and ≥2 postemployment digital chest radiographs. Radiographs were classified according to the International Labour Office guidelines by at least two B Readers. A final summary pneumoconiosis severity score (range, 0-13), accounting for both small and large opacities, was assigned to each chest radiograph. Progression was defined as an increase in severity score between a miner's radiographs over time.

RESULTS

Data for 130 former coal miners were analyzed. All miners were male and most (n = 114, 88%) had worked primarily in Kentucky. Information on race/ethnicity was not available. The most common job types were roof bolters (n = 51, 39%) and continuous miner operators (n = 46, 35%). Forty-one (31.5%) miners had evidence of radiographic disease progression after leaving the workforce, with a median of 3.6 years between first and latest postretirement radiograph. A total of 80 (62%) miners had evidence of pneumoconiosis on their latest radiograph, and two-thirds (n = 53) of these were classified as progressive massive fibrosis (PMF), the most severe form of the disease.

CONCLUSIONS

Postexposure progression can occur in former coal miners, emphasizing the potential benefits of continued radiographic follow-up postemployment. In addition to participating in disease screening throughout their careers to detect pneumoconiosis early and facilitate intervention, radiographic follow-up of former coal miners can identify new or progressive radiographic findings even after workplace exposure to respirable coal mine dust ends. Identification of progressive pneumoconiosis in former miners has potential implications for clinical management and eligibility for disability compensation.

Respiratory health of American Indian and Alaska Native coal miners participating in the Coal Workers' Health Surveillance Program, 2014-2019

BACKGROUND

In 2014, a federal rule reduced occupational exposure limits to coal mine dust and expanded medical surveillance eligibility beyond underground miners to surface and contract coal miners. This expansion may have provided an opportunity for more American Indian and Alaska Native (AI/AN) coal miners to participate in screening, since many surface coal mines are located near AI/AN communities and may employ AI/AN miners. Therefore we sought to better understand the respiratory health of AI/AN coal miners by characterizing prevalence of coal workers' pneumoconiosis (CWP), progressive massive fibrosis (PMF), and abnormal lung function in this population.

METHODS

Descriptive analysis of 1405 chest radiographs and 627 spirometry test results for AI/AN miners who participated in the Coal Workers' Health Surveillance Program (CWHSP) during 2014-2019 was conducted.

RESULTS

Most AI/AN miners (0-25+ years of tenure) were western United States residents (82.3%) and active surface miners (76.9%) with no underground tenure. Among miners with at least 10 years of tenure, prevalence of CWP was 3.0%, and of PMF was 0.3%. Lung function abnormalities were seen in 9.0% with primarily restrictive patterns.

CONCLUSIONS

The prevalence of CWP, PMF, and lung function abnormality among active and former AI/AN coal miners was higher than seen in a larger CWHSP study of active western miners working primarily underground with 10+ years of tenure. Interventions that eliminate or control coal mine dust exposure, identify miners with CWP early, and limit respiratory disease progression and complications remain vital for eliminating the preventable adverse health effects of coal mining. Comprehensive demographic data on the coal mining workforce are needed to improve CWHSP participation assessment.

Assessment of pneumoconiosis in surface coal miners after implementation of a national radiographic surveillance program, United States, 2014-2019

BACKGROUND

Pneumoconiosis can occur in surface coal miners. The Coal Workers' Health Surveillance Program (CWHSP) has only included surface coal miners as part of its regular disease surveillance since 2014. This analysis identifies the prevalence of pneumoconiosis among working surface coal miners participating in the CWHSP since their initial inclusion, through 2019.

METHODS

Working surface coal miners who had chest radiographs through the CWHSP from January 1, 2014 through December 31, 2019 were included in this analysis. Demographic information, mining tenure and occupation, and radiographic classifications according to the International Labour Office system were included from each miner's most recent encounter with the CWHSP. Prevalence ratios were calculated comparing the prevalence of the disease by region and occupation by log-binomial regression.

RESULTS

Pneumoconiosis was present in 109 (1.6%) surface coal miners, including 12 miners with progressive massive fibrosis, the most severe form of the disease. After taking surface mining tenure into account, surface miners in Central Appalachia (prevalence ratio [PR], 3.2; 95% confidence interval [CI], 2.2-4.7) and surface miners who worked as a driller or blaster (PR, 2.1; 95% CI, 1.3-3.5) were at increased risk of pneumoconiosis.

CONCLUSION

The occurrence of pneumoconiosis in surface coal miners supports including them within a systematic respiratory health surveillance program. The current surveillance findings are consistent with past findings of pneumoconiosis, particularly silicosis, in surface mining occupations such as drilling and blasting.

Transplantation for work-related lung disease in the USA

OBJECTIVES

Work-related lung diseases (WRLDs) are entirely preventable. To assess the impact of WRLDs on the US transplant system, we identified adult lung transplant recipients with a WRLD diagnosis specified at the time of transplant to describe demographic, payer and clinical characteristics of these patients and to assess post-transplant survival.

METHODS

Using US registry data from 1991 to 2018, we identified lung transplant recipients with WRLDs including coal workers' pneumoconiosis, silicosis, asbestosis, metal pneumoconiosis and berylliosis.

RESULTS

The frequency of WRLD-associated transplants has increased over time. Among 230 lung transplants for WRLD, a majority were performed since 2009; 79 were for coal workers' pneumoconiosis and 78 were for silicosis. Patients with coal workers' pneumoconiosis were predominantly from West Virginia (n=31), Kentucky (n=23) or Virginia (n=10). States with the highest number of patients with silicosis transplant were Pennsylvania (n=12) and West Virginia (n=8). Patients with metal pneumoconiosis and asbestosis had the lowest and highest mean age at transplant (48.8 and 62.1 years). Median post-transplant survival was 8.2 years for patients with asbestosis, 6.6 years for coal workers' pneumoconiosis and 7.8 years for silicosis. Risk of death among patients with silicosis, coal workers' pneumoconiosis and asbestosis did not differ when compared with patients with idiopathic pulmonary fibrosis.

CONCLUSIONS

Lung transplants for WRLDs are increasingly common, indicating a need for primary prevention and surveillance in high-risk occupations. Collection of patient occupational history by the registry could enhance case identification and inform prevention strategies.

Prevalence of spirometry-defined airflow obstruction in never-smoking working US coal miners by pneumoconiosis status

INTRODUCTION

This study estimated the prevalence of spirometry-defined airflow obstruction and coal workers' pneumoconiosis (CWP) among never-smoking coal miners participating in the National Institute for Occupational Safety and Health (NIOSH) Coal Workers' Health Surveillance Program (CWHSP).

METHODS

Data were from working miners screened by a CWHSP mobile unit who had valid spirometry and chest radiography results. Spirometry-defined airflow obstruction was determined when the ratio of forced expiratory volume in the first second to forced vital capacity is less than the lower limit of normal. Chest radiographs were classified according to the International Labour Office system to identify pneumoconiosis, including the most severe form of pneumoconiosis, progressive massive fibrosis (PMF).

RESULTS

Prevalence of airflow obstruction among never-smoking coal miners in this sample was 7.7% overall, 16.4% among miners with CWP and 32.3% among miners with PMF. Airflow obstruction was significantly associated with CWP and PMF.

CONCLUSIONS

There was a higher prevalence of airflow obstruction among never-smoking coal miners with pneumoconiosis compared with those without pneumoconiosis. These findings support prior research on airflow obstruction and smoking and show pneumoconiosis might present with an obstructive pattern regardless of smoking status.

Pneumoconiosis progression patterns in US coal miner participants of a job transfer programme designed to prevent progression of disease

OBJECTIVES

Pneumoconiosis prevalence and severity among US coal miners has been increasing for the past 20 years. An examination of the current approaches to primary and secondary prevention efforts is warranted. One method of secondary prevention is the Mine Safety and Health Administration-administered part 90 option programme where US coal miners with radiographic evidence of pneumoconiosis can exercise their right to be placed in a less dusty area of the mine. This study focuses on characterising the progression of disease among US coal miners who participated in the National Institute for Occupational Safety and Health-administered Coal Workers' Health Surveillance Programme (CWHSP) and exercised their part 90 job transfer option.

METHODS

Chest radiograph classifications of working underground coal miners who exercised their part 90 job transfer option during 1 January 1986 to 21 November 2016 and participated in the CWHSP during 1 January 1981 to 19 March 2019 were analysed.

RESULTS

513 miners exercised their part 90 option and participated in the CWHSP at least once during this time period. Of the 149 miners with ≥2 radiographs available, 48 (32%) showed progression after exercising part 90 and had more severe disease prior to exercising, compared with miners who did not progress (severity score of 2.8 vs 1.7, p=0.0002).

CONCLUSION

The part 90 job transfer option programme is not routinely used as intended to prevent progression of pneumoconiosis among US coal miners. The one-third of miners who participated in part 90 and continued to progress, exercised their part 90 option at a later stage of disease compared with non-progressors.

The National Institute for Occupational Safety and Health B Reader Certification Program-An Update Report (1987 to 2018) and Future Directions

OBJECTIVE

The National Institute for Occupational Safety and Health (NIOSH) B Reader Program provides the opportunity for physicians to demonstrate proficiency in the International Labour Office (ILO) system for classifying radiographs of pneumoconioses. We summarize trends in participation and examinee attributes and performance during 1987 to 2018.

METHODS

Since 1987, NIOSH has maintained details of examinees and examinations. Attributes of examinees and their examination performance were summarized. Simple linear regression was used in trend analysis of passing rates over time.

RESULTS

The mean passing rate for certification and recertification for the study period was 40.4% and 82.6%, respectively. Since the mid-1990s, the number of B Readers has declined and the mean age and years certified have increased.

CONCLUSIONS

To address the declining B Reader population, NIOSH is currently taking steps to modernize the program and offer more opportunities for training and testing.

Patterns of progressive massive fibrosis on modern coal miner chest radiographs

Clinical teaching generally asserts that large opacities of progressive massive fibrosis (PMF) on chest radiographs present primarily bilaterally in the upper lung zones, and with an elevated background profusion of small opacities. However, the contemporary basis for these descriptions is limited.Radiographs taken for the Coal Workers' Health Surveillance Program during 2000-2015 and previously determined to have large opacities ("PMF radiographs", n = 204), and a random 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 readings, 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.

Continued increase in prevalence of r-type opacities among underground coal miners in the USA

INTRODUCTION

Respirable crystalline silica exposure has been implicated in the resurgence of coal workers' pneumoconiosis (CWP) in the USA. A 2010 report found an increasing prevalence of r-type opacities, which are associated with silicosis lung pathology, on the radiographs of working underground coal miners in central Appalachia. This analysis updates that report by assessing the prevalence of r-type opacities during 2010-2018 compared with earlier decades.

METHODS

Data from the Coal Workers' Health Surveillance Program were used to calculate the prevalence of r-type opacities on radiographs of working underground coal miners. The data were restricted to radiographs taken during 1 January 1980 to 15 September 2018. The presence of r-type opacities was defined as an r-type classification for either the primary or secondary shape/size of small opacities. Prevalence ratios for r-type opacities were calculated using log binomial regression.

RESULTS

Radiograph classifications for 106 506 miners were included in analysis. For the USA overall, the prevalence of r-type opacities among miners with radiographs taken during 2010-2018 compared with 1980-1989 has increased (PR 2.4; 95% CI 1.9 to 3.0). For central Appalachia, the proportion of r-type opacities observed increased when comparing 1980-1989 to 2010-2018 (PR 6.0; 95% CI 4.6 to 7.9).

CONCLUSIONS

The prevalence of r-type opacities on the radiographs of Appalachian underground coal miners continues to increase, implicating exposure to crystalline silica in respirable coal mine dust. The current findings underscore the importance of monitoring and controlling exposure to silica in coal mines.

Interstitial Lung Diseases in the U.S. Mining Industry: Using MSHA Data to Examine Trends and the Prevention Effects of Compliance with Health Regulations, 1996-2015

Given the recent increase in dust-induced lung disease among U.S. coal miners and the respiratory hazards encountered across the U.S. mining industry, it is important to enhance an understanding of lung disease trends and the organizational contexts that precede these events. In addition to exploring overall trends reported to the Mine Safety and Health Administration (MSHA), the current study uses MSHA's enforcement database to examine whether or not compliance with health regulations resulted in fewer mine-level counts of these diseases over time. The findings suggest that interstitial lung diseases were more prevalent in coal mines compared to other mining commodities, in Appalachian coal mines compared to the rest of the United States, and in underground compared to surface coal mines. Mines that followed a relevant subset of MSHA's health regulations were less likely to report a lung disease over time. The findings are discussed from a lung disease prevention strategy perspective.

Continued Increase in Prevalence of Coal Workers' Pneumoconiosis in the United States, 1970-2017

OBJECTIVES

To update prevalence estimates for coal workers' pneumoconiosis (CWP) among working underground coal miners in the United States.

METHODS

We conducted a prevalence study using radiographs collected from 1970 to 2017. We classified each radiograph using international standards. We defined CWP as the presence of small opacities, with profusion greater than or equal to subcategory 1/0, or the presence of a large opacity larger than 1 centimeter.

RESULTS

Following a low point in the late 1990s, the national prevalence of CWP in miners with 25 years or more of tenure now exceeds 10%. In central Appalachia (Kentucky, Virginia, West Virginia), 20.6% of long-tenured miners have CWP. When we excluded miners from central Appalachia, the prevalence for the remainder of the United States was lower, but an increase since 2000 remains evident.

CONCLUSIONS

The national prevalence of CWP among working coal miners is increasing. This increase is most pronounced in central Appalachia. Current CWP prevalence estimates will likely be reflected in future trends for severe and disabling disease, including progressive massive fibrosis. Public Health Implications. Recently enacted protections to prevent coal mine dust exposure and identify CWP at its early stage remain essential to protect US coal miners.

Continued increase in lung transplantation for coal workers' pneumoconiosis in the United States

BACKGROUND

Severe coal workers' pneumoconiosis (CWP) is increasingly common, and sometimes requires lung transplantation.

METHODS

Using Organ Procurement and Transplantation Network data, we updated the trend for CWP-related lung transplants, described CWP patients who have been waitlisted but not transplanted, and characterized the primary payer of medical costs for CWP-related and other occupational lung disease transplants.

RESULTS

There have been at least 62 CWP-related lung transplants; 49 (79%) occurred in the last decade. The rate of these procedures has also increased. Twenty-seven patients were waitlisted but did not receive a transplant. Compared to other occupational lung diseases, transplants for CWP were more likely to be paid for by public insurance.

CONCLUSIONS

The increase in the frequency and rate of lung transplantation for CWP is consistent with the rising prevalence of severe CWP among U.S. coal miners. Effective exposure controls and identification of early stage CWP remain essential for protecting these workers.

Progressive Massive Fibrosis in Coal Miners From 3 Clinics in Virginia

This study describes the demographic and radiographic characteristics of 416 coal miners with progressive massive pulmonary fibrosis (PMF) identified by pneumoconiosis screening as part of the US Coal Workers’ Health Surveillance Program.

Coal miner participation in a job transfer program designed to prevent progression of pneumoconiosis, United States, 1986-2016

The Part 90 program was designed to prevent progression of pneumoconiosis in U.S. coal miners by establishing their right to transfer to a less dusty job in the mine. We calculated the proportion of Part 90-eligible miners who participated during 1986-2016, examined participation by region, and compared characteristics of miners by participation status. Of the 3,547 eligible miners, 14.4% exercised their Part 90 option. Miners working in states outside central Appalachia, and those with more severe pneumoconiosis, were more likely to participate. The primary goal of respiratory health surveillance of coal miners is early detection of disease so that preventive action can be taken. Future studies should seek to better understand factors influencing Part 90 program participation.

Radiographic features of importance in the National Institute for Occupational Safety and Health-administered Coal Workers' Health Surveillance Program: characterising the use of the 'other symbols'

OBJECTIVE

The National Institute for Occupation Safety and Health-administered Coal Workers' Health Surveillance Program (CWHSP) provides radiographic pneumoconiosis screening for US coal miners. Radiographs are classified by readers according to International Labour Office criteria. In addition to pneumoconiotic parenchymal and pleural lung abnormalities, readers document radiographic features of importance (other symbols). Other symbols are not meant to imply a diagnosis or interpretation but are relevant as they provide information beyond a pneumoconiosis classification for features related to dust exposure and other aetiologies. Our objective was to summarise other symbol data from 48 years of CWHSP participants.

METHODS

Chest radiograph classifications obtained from CWHSP participants between July 1968 and July 2016 were analysed. Any 'other symbol' indication from any of the readings were counted. Frequencies were tabulated by individual reader and those identified by any reader.

RESULTS

Of the 469 922 radiographs included in this study, nearly 15% had at least one reader identify a radiographic feature of importance. The most commonly identified other symbol was cancer (excluding mesothelioma) (6.83%), followed by emphysema (1.68%). Some features were rarely identified over the 48 years of data collection such as rheumatoid pneumoconiosis (n=46), pneumothorax (n=32), mesothelioma (n=12) and rounded atelectasis (n=4).

CONCLUSIONS

This is the largest study to date describing radiographic features of importance as part of routine chest radiographic surveillance. While these symbols are not diagnostic they can be used to describe features associated with dust exposure. One of the most commonly identified radiographic features in our population is emphysema which is associated with respirable dust exposure. These results can be compared with other dust exposed populations.

Evaluation of high blood pressure and obesity among US coal miners participating in the Enhanced Coal Workers' Health Surveillance Program

Since 2005, the Enhanced Coal Workers' Health Surveillance Program (ECWHSP) has offered respiratory examinations to coal miners in a mobile examination unit. As little is known about the cardiovascular health of coal miners, we describe the prevalence of high blood pressure (BP) and obesity among ECWHSP participants. During 2015, 1402 ECWHSP health examinations were performed. The prevalence of BP consistent with hypertension (systolic BP ≥ 140 mm Hg or diastolic BP ≥ 90 mm Hg), prehypertension (systolic BP 120-139 mm Hg or diastolic BP 80-89 mm Hg), and hypertensive crisis (systolic BP ≥ 180 mm Hg or diastolic BP ≥ 110 mm Hg) were calculated and compared with the US adult population using standardized morbidity ratios (SMRs). Most participants were male (N = 1317, 94%), White (N = 1303, 93%) and non-Hispanic (N = 1316, 94%). Thirty-one percent (N = 440) of participants had BP in the hypertensive range and 87% (N = 1215) were overweight/obese. Twenty-four participants (2%) had a BP reading consistent with a hypertensive crisis. Prevalence of obesity (52%, SMR = 1.52, 95% confidence interval = 1.41-1.64) and BP consistent with hypertension (31%, SMR = 1.60, 95% confidence interval = 1.45-1.76) was higher than the US adult population.The prevalence of obesity and BP consistent with hypertension in this population of coal miners is substantial, indicating a need for cardiovascular health interventions in coal mining communities.

Respiratory morbidity among U.S. coal miners in states outside of central Appalachia

BACKGROUND

Recent NIOSH publications have focused on the respiratory health of coal miners in central Appalachia, yet 57% of U.S. coal miners work in other regions. We characterized respiratory morbidity in coal miners from these regions.

METHODS

Active coal miners working outside of central Appalachia who received chest radiographs and/or spirometry during 2005-2015 were included. Chest radiographs were classified according to International Labour Office standards and spirometry was interpreted using the American Thoracic Society guidelines. Prevalence of coal workers' pneumoconiosis (CWP) and abnormal spirometry were compared by region.

RESULTS

A total of 103 (2.1%) miners had CWP. The eastern region had the highest prevalence (3.4%), followed by the western (1.7%), and interior (0.8%) regions. A total of 524 (9.3%) miners had abnormal spirometry.

CONCLUSIONS

CWP occurs in all U.S. coal mining regions. Prevalence of CWP was higher in the eastern region, but lower than levels reported in central Appalachia.

Pneumoconioses Radiographs in a Large Population of U.S. Coal Workers: Variability in A Reader and B Reader Classifications by Using the International Labour Office Classification

Purpose To assess the level of concordance between chest radiographic classifications of A and B Readers in a national surveillance program offered to U.S. coal miners over an approximate 36-year period. Materials and Methods The National Institute for Occupational Safety and Health (NIOSH) Coal Workers' Health Surveillance Program (CWHSP) is a surveillance program with nonresearch designation and is exempt from Human Subjects Review Board approval (11-DRDS-NR03). Thirty-six years of data (1979-2015) from the CWHSP were analyzed, which included all conventional screen-film radiographs with a classification by at least one A Reader and one B Reader. Agreement was assessed by using κ statistics; prevalence ratios were used to describe differences between A and B Reader determinations of image technical quality, small opacity profusion, and presence of large opacities and pleural abnormalities. Results The analysis included 79 185 matched A and B Reader chest radiograph classifications. A majority of both A and B Readers were radiologists (74.2% [213 of 287] vs 64.7% [22 of 34]; P = .04). A and B Readers had minimal agreement on technical image quality (κ = 0.0796; 95% confidence interval [CI]: 0.07, 0.08) and the distribution of small opacity profusion (subcategory κ, 0.2352; 95% CI: 0.22, 0.25). A Readers classified more images as "good" quality (prevalence ratio, 1.38; 95% CI: 1.35, 1.41) and identified more pneumoconiosis (prevalence ratio, 1.22; 95% CI: 1.20, 1.23). Conclusion A Readers classified substantially more radiographs with evidence of pneumoconiosis and classified higher small opacity profusion compared with B Readers. These observations reinforce the importance of multiple classifications by readers who have demonstrated ongoing competence in the International Labour Office classification system to ensure accurate radiographic classifications. ^© RSNA, 2017.

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

INTRODUCTION

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.

METHODS

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.

RESULTS

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.

DISCUSSION

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.

Lung transplantation is increasingly common among patients with coal workers' pneumoconiosis

BACKGROUND

The prevalence of coal workers' pneumoconiosis (CWP) in U.S. coal miners has increased, and severe presentations are increasingly common.

METHODS

We describe trends in lung transplantation during 1996-2014 for recipients with a primary diagnosis of CWP or pneumoconiosis unspecified, and we summarize recipient characteristics and estimate survival.

RESULTS

A total of 47 transplants were included; nearly three-quarters were performed during 2008-2014. All recipients were male, 96% were white, and the mean age was 56 years. Mean FEV1 % was 35%; mean FVC% was 53%. Mean time on a waitlist was 155 days, and 60% of transplants were bilateral. Median survival was 3.7 years.

CONCLUSIONS

These transplants reflect the use of a scarce resource for an entirely preventable disease, and highlight the need for enhanced efforts to reduce coal mine dust exposures.

Profusion of Opacities in Simple Coal Worker's Pneumoconiosis Is Associated With Reduced Lung Function

BACKGROUND

A large body of evidence demonstrates dose-response relationships of cumulative coal mine dust exposure with lung function impairment and with small-opacity profusion. However, medical literature generally holds that simple coal worker's pneumoconiosis (CWP) is not associated with lung function impairment. This study examines the relationship between small-opacity profusion and lung function in US underground coal miners with simple CWP.

METHODS

Miners were examined during 2005 to 2013 as part of the Enhanced Coal Workers' Health Surveillance Program. Work histories were obtained, and chest radiographs and spirometry were administered. Lung parenchymal abnormalities consistent with CWP were classified according to International Labor Organization guidelines, and reference values for FEV1 and FVC were calculated using reference equations derived from the third National Health and Nutrition Examination Survey. Differences in lung function were evaluated by opacity profusion, and regression models were fit to characterize associations between profusion and lung function.

RESULTS

A total of 8,230 miners were eligible for analysis; 269 had category 1 or 2 simple CWP. Decrements in FEV1 % predicted were nearly consistent across profusion subcategories. Clear decrements in FVC % predicted and FEV1/FVC were also observed, although these were less consistent. Controlling for smoking status, BMI, and mining tenure, each 1-unit subcategory increase in profusion was associated with decreases of 1.5% (95% CI, 1.0%-1.9%), 1.0% (95% CI, 0.6%-1.3%), and 0.6% (95% CI, 0.4%-0.8%) in FEV1 % predicted, FVC % predicted, and FEV1/FVC, respectively.

CONCLUSIONS

We observed progressively lower lung function across the range of small-opacity profusion. These findings address a long-standing question in occupational medicine and point to the importance of medical surveillance and respiratory disease prevention in this workforce.

Comparative Respiratory Morbidity of Former and Current US Coal Miners

We compared the prevalence of respiratory disease in former and current US coal miners using chest radiographs and lung functions collected from 2009 to 2013 among miners of the Appalachian and Interior US coalfields. We calculated prevalence ratios (PRs) of pneumoconiosis and impaired lung function. Significantly higher prevalences of pneumoconiosis (PR = 1.5; 95% confidence interval = 1.2, 2.0) and impaired lung function were observed among former miners compared with active miners. Former miners continue to suffer negative health effects from occupational coal mine dust exposure. The respiratory health of active and former miners is a global concern because international coal production is projected to increase for decades to come.

Community quarantine to interrupt Ebola virus transmission - Mawah Village, Bong County, Liberia, August-October, 2014

On September 30, 2014, the Bong County health officer notified the county Ebola task force of a growing outbreak of Ebola virus disease (Ebola) in Mawah, a village of approximately 800 residents. During September 9-16, household quarantine had been used by the community in response to a new Ebola infection. Because the infection led to a local outbreak that grew during September 17-20, county authorities suggested community quarantine be considered, and beginning on approximately September 20, the Fuamah District Ebola Task Force (Task Force) engaged Mawah leaders to provide education about Ebola and to secure cooperation for the proposed measures. On September 30, Bong County requested technical assistance to develop strategies to limit transmission in the village and to prevent spread to other areas. The county health team, with support from the Task Force and CDC, traveled to Mawah on October 1 and identified approximately two dozen residents reporting symptoms consistent with Ebola. Because of an ambulance shortage, 2 days were required, beginning October 1, to transport the patients to an Ebola treatment unit in Monrovia. Community quarantine measures, consisting of restrictions on entering or leaving Mawah, regulated river crossings, and market closures, were implemented on October 1. Local leaders raised concerns about availability of medical care and food. The local clinic was reopened on October 11, and food was distributed on October 12. The Task Force reported a total of 22 cases of Ebola in Mawah during September 9-October 2, of which 19 were fatal. During October 3-November 21, no new cases were reported in the village. Involving community members during planning and implementation helped support a safe and effective community quarantine in Mawah.

Changes in prevalence of chronic obstructive pulmonary disease and asthma in the US population and associated risk factors

Chronic lower airway diseases, including chronic obstructive pulmonary disease (COPD) and asthma, are currently the third leading cause of death in the United States. We aimed to evaluate changes in prevalence of and risk factors for COPD and asthma among the US adult population. We evaluated changes in prevalence of self-reported doctor-diagnosed COPD (i.e. chronic bronchitis and emphysema) and asthma and self-reported respiratory symptoms comparing data from the 1988-1994 and 2007-2010 National Health and Nutrition Examination Surveys. To investigate changes in the severity of each outcome over the two periods, we calculated changes in the proportions of spirometry-based airflow obstruction for each outcome. Prevalence of doctor-diagnosed chronic bronchitis and emphysema decreased significantly mainly among males, while asthma increased only among females. The self-reported disease and the respiratory symptoms were associated with increased prevalence of airflow obstruction for both periods. However, the prevalence of airflow obstruction decreased significantly in the second period among those with shortness of breath and doctor-diagnosed respiratory conditions (chronic bronchitis, emphysema, and asthma). COPD outcomes and asthma were associated with lower education, smoking, underweight and obesity, and occupational dusts and fumes exposure. Chronic lower airway diseases continue to be major public health problems. However, decreased prevalence of doctor-diagnosed chronic bronchitis and emphysema (in males) and decreased prevalence of airflow obstruction in those with respiratory symptoms and doctor-diagnosed respiratory diseases may indicate a declining trend and decrease in disease severity between the two periods. Continued focus on prevention of these diseases through public health interventions is prudent.

Small mine size is associated with lung function abnormality and pneumoconiosis among underground coal miners in Kentucky, Virginia and West Virginia

OBJECTIVES

To describe the prevalence of lung function abnormality and coal workers' pneumoconiosis (CWP) by mine size among underground coal miners in Kentucky, Virginia and West Virginia.

METHODS

During 2005-2012, 4491 miners completed spirometry and chest radiography as part of a health surveillance programme. Spirometry was interpreted according to American Thoracic Society and European Respiratory Society guidelines, and radiography per International Labour Office standards. Prevalence ratios (PR) were calculated for abnormal spirometry (obstructive, restrictive or mixed pattern using lower limits of normal derived from National Health and Nutrition Examination Survey (NHANES) III) and CWP among workers from small mines (≤50 miners) compared with those from large mines.

RESULTS

Among 3771 eligible miners, those from small mines were more likely to have abnormal spirometry (18.5% vs 13.8%, p<0.01), CWP (10.8% vs 5.2%, p<0.01) and progressive massive fibrosis (2.4% vs 1.1%, p<0.01). In regression analysis, working in a small mine was associated with 37% higher prevalence of abnormal spirometry (PR 1.37, 95% CI 1.16 to 1.61) and 2.1 times higher prevalence of CWP (95% CI 1.68 to 2.70).

CONCLUSIONS

More than one in four of these miners had evidence of CWP, abnormal lung function or both. Although 96% of miners in the study have worked exclusively under dust regulations implemented following the 1969 Federal Coal Mine Safety and Health Act, we observed high rates of respiratory disease including severe cases. The current approach to dust control and provision of safe work conditions for central Appalachian underground coal miners is not adequate to protect them from adverse respiratory health effects.

Validation of the international labour office digitized standard images for recognition and classification of radiographs of pneumoconiosis

RATIONALE AND OBJECTIVES

Chest radiographs are recommended for prevention and detection of pneumoconiosis. In 2011, the International Labour Office (ILO) released a revision of the International Classification of Radiographs of Pneumoconioses that included a digitized standard images set. The present study compared results of classifications of digital chest images performed using the new ILO 2011 digitized standard images to classification approaches used in the past.

MATERIALS AND METHODS

Underground coal miners (N = 172) were examined using both digital and film-screen radiography (FSR) on the same day. Seven National Institute for Occupational Safety and Health-certified B Readers independently classified all 172 digital radiographs, once using the ILO 2011 digitized standard images (DRILO2011-D) and once using digitized standard images used in the previous research (DRRES). The same seven B Readers classified all the miners' chest films using the ILO film-based standards.

RESULTS

Agreement between classifications of FSR and digital radiography was identical, using a standard image set (either DRILO2011-D or DRRES). The overall weighted κ value was 0.58. Some specific differences in the results were seen and noted. However, intrareader variability in this study was similar to the published values and did not appear to be affected by the use of the new ILO 2011 digitized standard images.

CONCLUSIONS

These findings validate the use of the ILO digitized standard images for classification of small pneumoconiotic opacities. When digital chest radiographs are obtained and displayed appropriately, results of pneumoconiosis classifications using the 2011 ILO digitized standards are comparable to film-based ILO classifications and to classifications using earlier research standards.

Increased respiratory disease mortality at a microwave popcorn production facility with worker risk of bronchiolitis obliterans

Background

Bronchiolitis obliterans, an irreversible lung disease, was first associated with inhalation of butter flavorings (diacetyl) in workers at a microwave popcorn company. Excess rates of lung-function abnormalities were related to cumulative diacetyl exposure. Because information on potential excess mortality would support development of permissible exposure limits for diacetyl, we investigated respiratory-associated mortality during 2000–2011 among current and former workers at this company who had exposure to flavorings and participated in cross-sectional surveys conducted between 2000–2003.

Methods

We ascertained workers' vital status through a Social Security Administration search. Causes of death were abstracted from death certificates. Because bronchiolitis obliterans is not coded in the International Classification of Disease 10^th revision (ICD-10), we identified respiratory mortality decedents with ICD-10 codes J40–J44 which encompass bronchitis (J40), simple and mucopurulent chronic bronchitis (J41), unspecified chronic bronchitis (J42), emphysema (J43), and other chronic obstructive pulmonary disease (COPD) (J44). We calculated expected number of deaths and standardized mortality ratios (SMRs) with 95% confidence intervals (CI) to determine if workers exposed to diacetyl experienced greater respiratory mortality than expected.

Results

We identified 15 deaths among 511 workers. Based on U.S. population estimates, 17.39 deaths were expected among these workers (SMR = 0.86; CI:0.48-1.42). Causes of death were available for 14 decedents. Four deaths among production and flavor mixing workers were documented to have a multiple cause of ‘other COPD’ (J44), while 0.98 ‘other COPD’-associated deaths were expected (SMR = 4.10; CI:1.12–10.49). Three of the 4 ‘other COPD’-associated deaths occurred among former workers and workers employed before the company implemented interventions reducing diacetyl exposure in 2001.

Conclusion

Workers at the microwave popcorn company experienced normal rates of all-cause mortality but higher rates of COPD-associated mortality, especially workers employed before the company reduced diacetyl exposure. The demonstrated excess in COPD-associated mortality suggests continued efforts to lower flavoring exposure are prudent.