SUPPLEMENT
Introduction to the Supplement Clinical Aspects of Occupational and Environmental Lung Disease
T
he American College of Chest Physicians sponsored conference entitled “Occupational and Environmental Lung Disease 2013,” was held on June 21 to 23, 2013, in Toronto, Ontario, Canada. Each presentation was an authoritative review of research and relevant to clinical care, public health, and public policy. Panel discussions provided opportunities for all to consider the information and present ideas for future investigations. Ten of these presentations are a part of this supplement to the Journal of Occupational and Environmental Medicine. Nearly all were delivered at the meeting in a “question and answer” format to invite the audience’s participation and to focus on specific issues where clinicians and specialists in public health may have the most concerns. Most of the chapters below are presented in this format. I have the pleasure of inviting the reader to review the presentations of the speakers. I have provided a brief summary of the chapters in this supplement. Work-related asthma is the most commonly recognized chronic occupational lung disease in developed countries. Susan Tarlo focused on seven clinical questions addressing definitions, causes, diagnosis, management, and emerging triggers of workrelated asthma. The answers are not all straightforward. She reports on the less than clear understanding of whether low-level exposures of irritants in the workplace can cause of asthma, although she is more forceful in her conclusion that the appropriate physician response to the initiation of asthma by a sensitizer in a worker is clear-cut—the worker must be removed. Yet, the advice provided by a physician when irritants in the workplace are shown to provoke asthma is less clear-cut. The answer may depend on the severity of asthma, whether exposures may be modified and the effectiveness of therapy. In addition to identifying the presence and extent of the clinical features associated with asthma, our diagnostic approach to asthma typically includes a determination of the reversibility of lung function tests and nonspecific airway hyperresponsiveness, as well as a response to asthma therapy. Catherine Lemaire addresses two additional noninvasive tools of interest, which are now used in clinical practice in specialized settings. The first is the assessment of eosinophilic airway inflammation through sputum cell analysis. The second is the measurement of the fractional concentration of exhaled nitric oxide. Both address airway inflammation and serve as correlates for disease severity. The assessment of the cell differential in the sputum cell analysis is likely to be more widely adopted as technical aspects of the sample analysis become less cumbersome. Fractional exhaled nitric oxide requires a measuring device and reasonably correlates with the number of sputum eosinophils, and thereby airway inflammation. The recent concerns about the respiratory health of members of the US military after exposures to fumes, released from the “burn
The author declares no conflict of interest. Address correspondence to: Daniel E. Banks, MD, MS, Professor, Department of Medicine, Uniformed Services University of the Health Sciences, Staff Physician, Brooke Army Medical Center, 2478 Stanley Rd, Suite 103, Fort Sam Houston, TX 78234 ([email protected]). C 2014 by American College of Occupational and Environmental Copyright Medicine DOI: 10.1097/JOM.0000000000000291
pits” in Iraq and Afghanistan, led Deepthi Sudhakar, with colleagues Cynthia Clagett and Lisa Zacher, to address the respiratory health in the military over the past century. Among other topics, the authors cited influenza epidemics, chemical gas exposures, asbestos exposures in Naval shipyard workers during World War II, the initial understanding of lung capillary leak syndrome in those seriously injured in Vietnam, and our concerns about the respiratory health of our current generation of soldiers. Indeed, each war seems to engender previously unappreciated challenges to the soldier’s respiratory health. Among those of us who practice pulmonary medicine, there is the recognition that it is important to identify respiratory impairment in our patients, and if justified, quantitate the degree of disability so that the patient may receive appropriate compensation. I appreciate the clearly presented case-based approach that Aksay Sood has used to educate his colleagues. Using cases for teaching, the reader can relate to the clinical situation and apply the very formal rules of measuring the extent of disability to determine the outcome. All of this is made more complicated by extending the rules to asthma, where there is disability on a relative “periodic” basis, and by the recognition that the different disability granting agencies have their own rules. Although America appears to becoming less dependent on coal as an energy source, those who develop coal-induced lung disease often do so after a considerable number of years of exposure. Scott Laney and David Weissman provide an updated and cohesive approach to lung diseases in miners, making it clear that as long as we mine coal, the risks for dust-induced lung diseases cannot be minimized, that airway obstruction is associated with coal dust exposure, and that the natural history of this disease is often altered by the presence of silica, an element which is much more fibrogenic than coal. The presence of a substantial amount of silica in the dust can dramatically affect the outcome of coal dust exposures. Regardless of the number of federal regulations to minimize exposures, lung disease in coal miners has continued and looks to remain with us. Vernon Lappi, with his colleagues Diane Radnoff and Phil Karpluk, reports on workplace samples of free crystalline silica collected from 2009 to 2013 and claims of silicosis presented to the Alberta Workers Compensation Board from 2000 to 2009. Approximately 60% of the samples exceeded the Alberta occupational exposure limit and one third of the samples exceed the National Institute for Occupational Safety and Health-recommended standard (approximately half of the current US Mine Safety and Health Administration enforceable permissible exposure limit). Excessive exposures occurred in a variety of Alberta industries, including workplaces not generally considered to be associated with significant amounts of airborne respirable silica. Yet, many excessive exposures were measured at the same workplaces. From 2000 to 2009, there were 29 cases of silicosis. The authors present an honest discussion of how to address the data, whether the information regarding the number of newly diagnosed cases reflects the true extent of the epidemic of this disease, and the concern that these excessive exposures are likely to be associated with future disease. Upon initial consideration, it may not seem intuitive to link obstructive sleep apnea (OSA) or gastroesophageal reflux in first responder firemen and emergency medical service workers exposed
JOEM r Volume 56, Number 10S, October 2014 Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
S1
JOEM r Volume 56, Number 10S, October 2014
Banks
to dusts and fumes released from the World Trade Center (WTC) on 9/11. Nevertheless, Michelle Glaser, and her colleagues from New York City, showed that those with the highest level of WTC exposure were more likely to be diagnosed with severe OSA, that all OSA outcomes were significantly associated with gastroesophageal reflux disease, and that OSA was present in over 80% of those tested. The association between OSA and WTC exposure could be explained by chronic inflammation in the upper airway, leading to a decreased airway diameter. This anatomic change could explain apneic and hypopneic periods associated with airways relaxation, as noted in those with OSA. There were two presentations that addressed the important public health and policy issues of climate change and air pollution and their impact on lung health. Daniel Gerardi and Roy Kellerman point out that the health effects of climate change, mediated by greenhouse gases, can increase the prevalence of respiratory diseases, and be associated with exacerbations of chronic lung disease, premature mortality, allergic responses, and a decline in lung function. In a similar manner, Yuh-Chin Huang, writing about the effects of air pollution on the lung, has provided insight into the world-wide impact of air pollution on mortality. The World Health Organization has estimated that approximately 1.3 million individuals die each year on the basis of these exposures. The primary culprits in outdoor air pollution responsible for adverse effects are PM2.5 and ozone (O3 ). Short-term exposure to PM2.5 increases cardiopulmonary morbidity and mortality, whereas long-term exposure to particles of this size
S2
has been linked to adverse perinatal outcomes and lung cancer. Excessive O3 exposure is known to increase respiratory morbidity. In both of these reports, the most vulnerable patient populations—the elderly, children, and those in distressed socioeconomic strata—are at most risk. Finally, although a tremendous number of manuscripts have addressed the health of workers exposed to asbestos, there are issues that remain less than fully defined. I listed a number of issues and attempted to address three. In the first instance, one of the criteria for the diagnosis of asbestosis is a sufficient exposure to dust. What does that mean? A second question relates to the recognition that there had been little change in the world-wide incidence of mesothelioma, despite many countries implementing bans and lessening exposures. Why is this the case? A final query considered how those at risk for asbestos-related lung cancer should be medically screened. Finally, I would remiss if I did not acknowledge the generous support and guidance of the editor Paul Brandt-Rauf, MD, and the very capable editorial assistance of Ms Marjorie Spraycar and Ms Kerry O’Rourke, in assembling this work and assisting the authors. I am most grateful. Daniel E. Banks, MD, MS Department of Medicine, Uniformed Services University of the Health Sciences, and Brooke Army Medical Center, Fort Sam Houston, Tex.
C 2014 American College of Occupational and Environmental Medicine
Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Introduction to the Supplement Clinical Aspects of Occupational and Environmental Lung Disease
T
he American College of Chest Physicians sponsored conference entitled “Occupational and Environmental Lung Disease 2013,” was held on June 21 to 23, 2013, in Toronto, Ontario, Canada. Each presentation was an authoritative review of research and relevant to clinical care, public health, and public policy. Panel discussions provided opportunities for all to consider the information and present ideas for future investigations. Ten of these presentations are a part of this supplement to the Journal of Occupational and Environmental Medicine. Nearly all were delivered at the meeting in a “question and answer” format to invite the audience’s participation and to focus on specific issues where clinicians and specialists in public health may have the most concerns. Most of the chapters below are presented in this format. I have the pleasure of inviting the reader to review the presentations of the speakers. I have provided a brief summary of the chapters in this supplement. Work-related asthma is the most commonly recognized chronic occupational lung disease in developed countries. Susan Tarlo focused on seven clinical questions addressing definitions, causes, diagnosis, management, and emerging triggers of workrelated asthma. The answers are not all straightforward. She reports on the less than clear understanding of whether low-level exposures of irritants in the workplace can cause of asthma, although she is more forceful in her conclusion that the appropriate physician response to the initiation of asthma by a sensitizer in a worker is clear-cut—the worker must be removed. Yet, the advice provided by a physician when irritants in the workplace are shown to provoke asthma is less clear-cut. The answer may depend on the severity of asthma, whether exposures may be modified and the effectiveness of therapy. In addition to identifying the presence and extent of the clinical features associated with asthma, our diagnostic approach to asthma typically includes a determination of the reversibility of lung function tests and nonspecific airway hyperresponsiveness, as well as a response to asthma therapy. Catherine Lemaire addresses two additional noninvasive tools of interest, which are now used in clinical practice in specialized settings. The first is the assessment of eosinophilic airway inflammation through sputum cell analysis. The second is the measurement of the fractional concentration of exhaled nitric oxide. Both address airway inflammation and serve as correlates for disease severity. The assessment of the cell differential in the sputum cell analysis is likely to be more widely adopted as technical aspects of the sample analysis become less cumbersome. Fractional exhaled nitric oxide requires a measuring device and reasonably correlates with the number of sputum eosinophils, and thereby airway inflammation. The recent concerns about the respiratory health of members of the US military after exposures to fumes, released from the “burn
The author declares no conflict of interest. Address correspondence to: Daniel E. Banks, MD, MS, Professor, Department of Medicine, Uniformed Services University of the Health Sciences, Staff Physician, Brooke Army Medical Center, 2478 Stanley Rd, Suite 103, Fort Sam Houston, TX 78234 ([email protected]). C 2014 by American College of Occupational and Environmental Copyright Medicine DOI: 10.1097/JOM.0000000000000291
pits” in Iraq and Afghanistan, led Deepthi Sudhakar, with colleagues Cynthia Clagett and Lisa Zacher, to address the respiratory health in the military over the past century. Among other topics, the authors cited influenza epidemics, chemical gas exposures, asbestos exposures in Naval shipyard workers during World War II, the initial understanding of lung capillary leak syndrome in those seriously injured in Vietnam, and our concerns about the respiratory health of our current generation of soldiers. Indeed, each war seems to engender previously unappreciated challenges to the soldier’s respiratory health. Among those of us who practice pulmonary medicine, there is the recognition that it is important to identify respiratory impairment in our patients, and if justified, quantitate the degree of disability so that the patient may receive appropriate compensation. I appreciate the clearly presented case-based approach that Aksay Sood has used to educate his colleagues. Using cases for teaching, the reader can relate to the clinical situation and apply the very formal rules of measuring the extent of disability to determine the outcome. All of this is made more complicated by extending the rules to asthma, where there is disability on a relative “periodic” basis, and by the recognition that the different disability granting agencies have their own rules. Although America appears to becoming less dependent on coal as an energy source, those who develop coal-induced lung disease often do so after a considerable number of years of exposure. Scott Laney and David Weissman provide an updated and cohesive approach to lung diseases in miners, making it clear that as long as we mine coal, the risks for dust-induced lung diseases cannot be minimized, that airway obstruction is associated with coal dust exposure, and that the natural history of this disease is often altered by the presence of silica, an element which is much more fibrogenic than coal. The presence of a substantial amount of silica in the dust can dramatically affect the outcome of coal dust exposures. Regardless of the number of federal regulations to minimize exposures, lung disease in coal miners has continued and looks to remain with us. Vernon Lappi, with his colleagues Diane Radnoff and Phil Karpluk, reports on workplace samples of free crystalline silica collected from 2009 to 2013 and claims of silicosis presented to the Alberta Workers Compensation Board from 2000 to 2009. Approximately 60% of the samples exceeded the Alberta occupational exposure limit and one third of the samples exceed the National Institute for Occupational Safety and Health-recommended standard (approximately half of the current US Mine Safety and Health Administration enforceable permissible exposure limit). Excessive exposures occurred in a variety of Alberta industries, including workplaces not generally considered to be associated with significant amounts of airborne respirable silica. Yet, many excessive exposures were measured at the same workplaces. From 2000 to 2009, there were 29 cases of silicosis. The authors present an honest discussion of how to address the data, whether the information regarding the number of newly diagnosed cases reflects the true extent of the epidemic of this disease, and the concern that these excessive exposures are likely to be associated with future disease. Upon initial consideration, it may not seem intuitive to link obstructive sleep apnea (OSA) or gastroesophageal reflux in first responder firemen and emergency medical service workers exposed
JOEM r Volume 56, Number 10S, October 2014 Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
S1
JOEM r Volume 56, Number 10S, October 2014
Banks
to dusts and fumes released from the World Trade Center (WTC) on 9/11. Nevertheless, Michelle Glaser, and her colleagues from New York City, showed that those with the highest level of WTC exposure were more likely to be diagnosed with severe OSA, that all OSA outcomes were significantly associated with gastroesophageal reflux disease, and that OSA was present in over 80% of those tested. The association between OSA and WTC exposure could be explained by chronic inflammation in the upper airway, leading to a decreased airway diameter. This anatomic change could explain apneic and hypopneic periods associated with airways relaxation, as noted in those with OSA. There were two presentations that addressed the important public health and policy issues of climate change and air pollution and their impact on lung health. Daniel Gerardi and Roy Kellerman point out that the health effects of climate change, mediated by greenhouse gases, can increase the prevalence of respiratory diseases, and be associated with exacerbations of chronic lung disease, premature mortality, allergic responses, and a decline in lung function. In a similar manner, Yuh-Chin Huang, writing about the effects of air pollution on the lung, has provided insight into the world-wide impact of air pollution on mortality. The World Health Organization has estimated that approximately 1.3 million individuals die each year on the basis of these exposures. The primary culprits in outdoor air pollution responsible for adverse effects are PM2.5 and ozone (O3 ). Short-term exposure to PM2.5 increases cardiopulmonary morbidity and mortality, whereas long-term exposure to particles of this size
S2
has been linked to adverse perinatal outcomes and lung cancer. Excessive O3 exposure is known to increase respiratory morbidity. In both of these reports, the most vulnerable patient populations—the elderly, children, and those in distressed socioeconomic strata—are at most risk. Finally, although a tremendous number of manuscripts have addressed the health of workers exposed to asbestos, there are issues that remain less than fully defined. I listed a number of issues and attempted to address three. In the first instance, one of the criteria for the diagnosis of asbestosis is a sufficient exposure to dust. What does that mean? A second question relates to the recognition that there had been little change in the world-wide incidence of mesothelioma, despite many countries implementing bans and lessening exposures. Why is this the case? A final query considered how those at risk for asbestos-related lung cancer should be medically screened. Finally, I would remiss if I did not acknowledge the generous support and guidance of the editor Paul Brandt-Rauf, MD, and the very capable editorial assistance of Ms Marjorie Spraycar and Ms Kerry O’Rourke, in assembling this work and assisting the authors. I am most grateful. Daniel E. Banks, MD, MS Department of Medicine, Uniformed Services University of the Health Sciences, and Brooke Army Medical Center, Fort Sam Houston, Tex.
C 2014 American College of Occupational and Environmental Medicine
Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
