Cara N. Halldin

Resurgence of a Debilitating and Entirely Preventable Respiratory Disease among Working Coal Miners

To the Editor: For more than 40 years, the National Institute for Occupational Safety and Health (NIOSH) has monitored trends in coal workers’ pneumoconiosis, including progressive massive fibrosis (PMF). PMF is an advanced, debilitating, and lethal form of coal workers’ pneumoconiosis with limited, primarily palliative treatment options and no cure. As part of ongoing surveillance efforts, NIOSH administers the Coal Workers’ Health Surveillance Program (CWHSP), which offers underground coal miners periodic chest radiographs and confidentially informs them of their pneumoconiosis status (1). Just 15 years ago, PMF was virtually eradicated, with a prevalence of 0.08% among all CWHSP participants and 0.33% among active underground miners with at least 25 years of mining tenure. Since that time, the national prevalence of PMF identified through the CWHSP has increased; the rate of increase in the central Appalachian states of Kentucky, Virginia, and West Virginia has been especially pronounced (Figure 1). Excessive inhalation of coal mine dust is the sole cause of PMF in working coal miners, so this increase can only be the result of overexposures and/or increased toxicity stemming from changes in dust composition (2). During 1998 to 2012, NIOSH identified 154 cases of PMF among CWHSP participants, 125 of whom were long-tenured underground coal miners in central Appalachia. In 2012, the prevalence of PMF in this group of working miners reached 3.23% (5-year moving average), the highest level since the early 1970s. At the same time, NIOSH documented cases of PMF among surface coal miners with little or no underground mining tenure (3). Figure 1. Prevalence of progressive massive fibrosis among working underground coal miners with 25 or more years of underground mining tenure (1974–2012) in Kentucky, Virginia, and West Virginia, according to the Coal Workers’ Health Surveillance ... Each of these cases is a tragedy and represents a failure among all those responsible for preventing this severe disease. This year marks the 45th anniversary of the Federal Coal Mine Health and Safety Act. In that legislation, Congress enacted enforceable dust standards to reduce the incidence of coal workers’ pneumoconiosis and eliminate PMF among underground coal miners (4). Despite readily available dust control technology and best practices guidance (5), recent findings suggest dust exposures have not been adequately controlled and that a substantial portion of U.S. coal miners continue to develop PMF. On August 1, 2014, NIOSH issued an interim final rule modifying existing regulations to include surface coal miners in the CWHSP (6). In addition, the interim final rule expands medical surveillance beyond occupational history and chest radiography to include respiratory symptom assessment and spirometry testing for the recognition of undiagnosed chronic obstructive pulmonary disease among all working coal miners. We believe that expanded medical surveillance is an important part of ensuring success in efforts to protect U.S. coal miners from this deadly but entirely preventable disease.

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.

Debilitating Lung Disease Among Surface Coal Miners With No Underground Mining Tenure

Objective: To characterize exposure histories and respiratory disease among surface coal miners identified with progressive massive fibrosis from a 2010 to 2011 pneumoconiosis survey. Methods: Job history, tenure, and radiograph interpretations were verified. Previous radiographs were reviewed when available. Telephone follow-up sought additional work and medical history information. Results: Among eight miners who worked as drill operators or blasters for most of their tenure (median, 35.5 years), two reported poor dust control practices, working in visible dust clouds as recently as 2012. Chest radiographs progressed to progressive massive fibrosis in as few as 11 years. One miners lung biopsy demonstrated fibrosis and interstitial accumulation of macrophages containing abundant silica, aluminum silicate, and titanium dust particles. Conclusions: Overexposure to respirable silica resulted in progressive massive fibrosis among current surface coal miners with no underground mining tenure. Inadequate dust control during drilling/blasting is likely an important etiologic factor.

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.

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.

Forewarning of Poliovirus Outbreaks in the Horn of Africa: An Assessment of Acute Flaccid Paralysis Surveillance and Routine Immunization Systems in Kenya

BACKGROUND Although the Horn of Africa region has successfully eliminated endemic poliovirus circulation, it remains at risk for reintroduction. International partners assisted Kenya in identifying gaps in the polio surveillance and routine immunization programs, and provided recommendations for improved surveillance and routine immunization during the health system decentralization process. METHODS Structured questionnaires collected information about acute flaccid paralysis (AFP) surveillance resources, training, data monitoring, and supervision at provincial, district, and health facility levels. The routine immunization program information collected included questions about vaccine and resource availability, cold chain, logistics, health-care services and access, outreach coverage data, microplanning, and management and monitoring of AFP surveillance. RESULTS Although AFP surveillance met national performance standards, widespread deficiencies and limited resources were observed and reported at all levels. Deficiencies were related to provider knowledge, funding, training, and supervision, and were particularly evident at the health facility level. CONCLUSIONS Gap analysis assists in maximizing resources and capacity building in countries where surveillance and routine immunization lag behind other health priorities. Limited resources for surveillance and routine immunization systems in the region indicate a risk for additional outbreaks of wild poliovirus and other vaccine-preventable illnesses. Monitoring and evaluation of program strengthening activities are needed.

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.

Misclassification of occupational disease in lung transplant recipients

Data from the United States Organ Procurement and Transplantation Network (OPTN) registry have been analyzed in recent years to assess post–lung transplant (LT) survival in occupational lung disease patients.1–3 Registry data include diagnosis codes with limited specificity; each patient is assigned a diagnosis code at waitlist candidacy, at listing, and at LT, and these codes can differ. The use of both numeric and free-text data can produce incompatible or unlikely diagnosis code pairings (such as a numeric code for idiopathic pulmonary fibrosis with a paired free-text entry of “silicosis”). The resulting misclassification could bias findings related to patient characteristics, post-LT survival comparisons and other measures used to summarize outcomes.

Prevalence of airflow obstruction among ever-employed US adults aged 18–79 years by longest held occupation group: National Health and Nutrition Examination Survey 2007–2010

Objectives To estimate the prevalence of spirometry-defined airflow obstruction among ever-employed US adults. Methods Data from the 2007 to 2010 National Health and Nutrition Examination Survey (NHANES) for adults 18–79 years with valid spirometry and longest held occupation were analysed. The age-standardised prevalence of spirometry-defined airflow obstruction was estimated overall and by smoking status. Results Age-standardised prevalence of airflow obstruction was 13.7% (95% CI 12.4% to 15.0%) and was highest in participants aged 60–79 years (17.4%, 95% CI 15.2% to 19.6%), males (14.8%, 95% CI 12.0% to 17.6%), non-Hispanic whites (15.4%, 95% CI 13.8% to 16.7%) and ever smokers (19.1%, 95% CI 16.6% to 21.5%). Age-standardised prevalence of airflow obstruction was >20% for installation, maintenance and repair occupations (p=22.1%, 95% CI 16.5% to 27.8%), and for construction and extraction occupations (20.7%, 95% CI 13.5% to 27.9%). Conclusions Prevalence of airflow obstruction varied by demographic characteristics and occupational factors with a higher prevalence among ever smokers for most demographic characteristics and occupational factors. Study findings emphasise the importance of monitoring the lung function of workers in occupations with a high prevalence of airflow obstruction.