Document X7ykyKVOoeQGVNmgXM6p7no14

CHEST Official publication of the American C ollege of Chest Physicians American College of Chest Physicians Consensus Statement on the Respiratory Health Effects of Asbestos Daniel E. Banks, Runhua Shi, Jerry McLarty, Clayton T. Cowl, Dorsett Smith, Susan M. Tarlo, Feroza Daroowalla, John Balmes and Michael Baumann Chest 2009;135;1619-1627 DOI 10.1378/chest.08-1345 The online version of this article, along with updated information and services can be found online on the World Wide Web at: http://www.chestjoumal.org/content/135/6/1619.full.html CHEST is the official journal of the American College of Chest Physicians. It has been published monthly since 1935. Copyright 2009 by the American College of Chest Physicians, 3300 Dundee Road, Northbrook, IL 60062. All rights reserved. No part of this article or PDF may be reproduced or distributed without the prior written permission of the copyright holder. (http://www.chestjournal.org/site/misc/reprints.xhtml) ISSN:0012-3692 Downloaded from www.chestjournal.org by guest on August 25, 2009 Copyright 2009 American College of Chest Physicians CHEST Consensus Statement American College of Chest Physicians Consensus Statement on the Respiratory Health Effects of Asbestos* Results of a Delphi Study Daniel E. Banks, MD, MS, FCCP; Runhua Shi, MD, PhD; Jerry McLarty, PhD; Clayton T. Cowl, MD, MS, FCCP; Dorsett Smith, MD, FCCP; Susan M. Tarlo, MBBS, FCCP; Feroza Daroowalla, MD, FCCP; John Balmes, MD, FCCP; and Michael Baumann, MD, MS, FCCP Background: The diagnosis of and criteria for the evaluation of asbestos-related disease impairment remains controversial after decades of research. Assessing agreement among experts who study pneumoconiosis, and diagnose and treat patients with asbestos-related respiratory conditions may be the first step in clarifying clinical and forensic/administrative issues associated with asbestos-related pulmonary conditions. Methods: We conducted a Delphi study, an iterative method of obtaining consensus among a group of experts. An expert panel was identified using an objective, nonbiased algorithm, based on the number of asbestos-related disease publications authored during the preceding 10-year period. Identified experts were invited to participate by accessing an Internet site. Each expert was presented statements developed by the authors regarding the diagnosis or treatment of asbestos-related disease; experts then ranked their degree of agreement or disagreement utilizing an 11-level modified Likert scale for each statement. Each expert was asked to justify their selection and to suggest references in support of their opinion. The Wilcoxon signed rank test and the interquartile range were used to define "consensus." The results of the collective Likert rankings, deidentified comments, and suggested references as well as the initial consensus results were then provided to the participating experts. Each panel member then ranked their extent of agreement with a modified statement for which consensus was not achieved. The process was repeated three times. Results: Consensus was achieved on all but 9 of 32 statements. Conclusions: Consensus was not achieved for nine statements. These statements may be topics for future research. (CHEST 2009; 135:1619-1627) Abbreviations: ACCP = American College of Chest Physicians; ATS = American Thoracic Society; HRCT = highresolution CT; IQR = interquartile range Executive Summary Objective: To provide expert-based consensus opinions for the diagnosis and documentation of asbestos-related lung disease, an area of occupational medicine that has remained con troversial after decades of research. The Amer ican Thoracic Society published criteria for the diagnosis of asbestosis in 1986 and revised these criteria in 2004, yet the data still are not uni formly applied. Process: Consensus opinions were derived us ing a systematic, iterative Delphi process. After developing strict criteria for inclusion, a panel of international experts was formed from an exhaustive literature search using a method that was intended to be as free of bias as practically possible. A set of 25 important state ments about the diagnosis of asbestos-related disease was constructed by the American Col lege of Chest Physicians (ACCP) with additional input from the Workers' Compensation Board www.chestjournal.org CHEST/135/6/JUNE, 2009 Downloaded from www.chestjournal.org by guest on August 25, 2009 Copyright 2009 American College of Chest Physicians 1619 of Alberta, Canada. These statements, which included sentinel topics central to the diagnosis and forensic assessment of asbestos-related respi ratory disease, were ranked independently by panel members using a modified Likert scale. Seven more statements were added during the Delphi process as a result of suggestions from the expert panel. A rigorous statistical method was used to quantitate the degree of consensus. Outcome: Consensus was reached on 23 of the 32 statements and formed the basis for this document. These statements included agree ment on the associations between asbestos ex posure and the development of radiographic pleural or parenchymal abnormalities, clinical associations between exposure based on a good environmental and occupational history and the development of disease, diagnostic utility of high-resolution CT scan of the chest, as well as increased risk of bronchogenic carcinoma and documented asbestos exposure even without documentation of asbestos fibers in respiratory tissue of the patient. Consensus was not at tained regarding nine statements; these state ments included questions of utility regarding chest radiographs and high-resolution CT scan of the chest, the relationship between asbestos exposure and pleural plaques, and the extent of risk for the development of lung cancer in the face of asbestos exposure. Validation: Consensus opinions were re viewed by the authors, the ACCP Occupational and Environmental Medicine NetWork Steer ing Committee, the ACCP Health and Science Policy Committee, and the Executive Commit tee of the ACCP Board of Regents. Sponsors: The ACCP and the Workers' Com pensation Board of Alberta. n 1986, the American Thoracic Society (ATS) published criteria for the diagnosis of asbestosis,1 yet these criteria are not typically uniformly applied. There is disagreement regarding a number of the health issues associated with respiratory exposure to* *From the Department ofMedicine (Drs. Banks, Shi, and McLarty), Louisiana State University School of Medicine, Shreveport, LA; the Divisions of Pulmonary & Critical Care Medicine, and Preventive, Occupational & Aerospace Medicine (Dr. Cowl), Mayo Clinic, Rochester, MN; the Department of Medicine (Dr. Smith), University of Washington School of Medicine, Seattle, WA; the Department of Medicine (Dr. Tarlo), University of Toronto, Toronto, ON, Canada; Stony Brook University Health Science Center (Dr. Daroowalla), Stony Brook, NY; the Depart ment of Occupational and Environmental Medicine (Dr. Balmes), University of California at San Francisco, San Francisco, CA; and the Department of Medicine (Dr. Baumann), University of Missis sippi Medical Center, Jackson, MS. asbestos.2-3 Manuscripts showing diametrically oppo site conclusions regarding asbestos-related exposure and impairments can be identified easily. For exam ple, proponents of banning asbestos in all applica tions use peer-reviewed literature to buoy their arguments, yet others use objective data to support their opinion that the health risks of asbestos or The questions were developed and revised for each round by the members of the working group as a whole. Drs. Shi and McLarty developed the Web site and the statistical analysis for each round. Drs. Banks, Shi, and McLarty wrote the manuscript with the approval of the members of the working group. This work was performed at the Louisiana State University School of Medicine in Shreveport, LA. This project was commis sioned by the ACCP and can be considered an "official" project of this organization. The ACCP provided a number of neckties embroidered with the ACCP logo to be distributed to partici pants who served on the expert panel in this study. The Workers' Compensation Board of Alberta provided financial support of $25,000 to support the project. Vernon Lappi, MD, serves as the medical director of medical services at the Workers' Compensation Board of Alberta, Canada. The Feist-Weiller Cancer Center of the Louisiana State University School of Medicine in Shreveport provided computer support for this project. Several physicians who participated in the Delphi project on asbestos have cared for patients, offered legal consultation, and/or testified in medical legal matters regarding asbestosrelated diseases. Dr. Banks has served as a consultant for both plaintiffs and defendants regarding the pulmonary health effects of occupational dust exposure. He has provided no legal consult ing regarding the health effects of asbestos exposure within the past 10 years. Dr. Cowl has evaluated and treated patients with asbestos-related lung disease but has not participated in any litigation or performed legal consulting work related to asbestos exposure or asbestos-related lung disease. Dr. Smith has evalu ated > 1,000 patients with asbestos exposure and > 150 patients with mesothelioma. He has served as a legal expert witness on multiple occasions, testifying primarily for defendants. He has authored articles and book chapters related to asbestos-related disease; his latest publication was in 2005. Most recently, he has evaluated patients with asbestos exposure primarily for forensic aspects of workers' compensation systems in the northwestern United States. He has been a radiographic "B-reader" since 1980 and has read multiple radiographs with pneumoconioses. Dr. Tarlo has served as a clinical consultant for patients referred by their physicians or by the Ontario Workplace Safety and Insur ance Board but has not been involved with litigation for asbestosrelated diseases. Dr. Daroowalla has served as a clinical consul tant for patients referred by their physicians but has not been involved with litigation for asbestos-related diseases. Dr. Balmes has served as a medical consultant for both plaintiffs and defendants, but primarily for plaintiff counsel, in the role of expert in the pulmonary health effects of occupational exposure to asbestos. However, he has performed no legal work regarding the topic of asbestos exposure or related disease in the past 5 years. Drs. Shi, McLarty, and Baumann have reported to the ACCP that no significant conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article. Manuscript received May 27, 2008; revision accepted February 25, 2009. Reproduction ofthis article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal. org/site/misc/reprints.xhtml). Correspondence to: Daniel E. Banks, MD, MS, Professor and Head, Department of Medicine, Louisiana State University School of Medicine, Room 6-203, 1501 Kings Hwy, Shreveport, LA 71130; e-mail: dbanks3@lsuhsc.edu DOI: 10.1378/chest.08-1345 1620 Consensus Statement Downloaded from www.chestjournal.org by guest on August 25, 2009 Copyright 2009 American College of Chest Physicians related fibers may be acceptable in certain situa tions.4-6 There is disagreement regarding whether asbestosis must be present to attribute lung cancer to an asbestos effect,7-8 how best to gauge the risk of asbestos-containing materials in schools and offic es,9-10 and if the presence of pleural plaques in creases lung cancer risk11-14 or whether other can cers outside of the respiratory tract are caused by asbestos exposure.15-16 Finally, there remains sub stantial disagreement as to whether a profusion score of International Labor Organization category 1/0 is sufficient to make the diagnosis of asbestosis. For example, in the most recent ATS statement,17 a "critical distinction is made between films that are suggestive but not presumptively diagnostic (0/1) and those that are presumptively diagnostic but not unequivocal (1/0)." Although some of these conclu sions may have little direct bearing on the under standing of the health effects of asbestos exposure, a more systematic approach to answering these and other questions may be more relevant to understand ing the risks associated with asbestos exposure and eventual administrative decisions reflecting equita ble compensation to affected patients. The goal of this study was to address these prob lems and to assess the health effects of asbestos exposure using the Delphi framework of consensus assessment using knowledge extracted from experts. This method promotes the resolution of "disputed" topics by iteratively polling experts and providing sequential feedback to all panel participants regard ing the responses elicited from other experts. We hoped to draw consensus opinions regarding a vari ety of diagnostic, forensic, and administrative issues stemming from clarified statements associated with asbestos exposure health effects. Drs. Banks, Shi, and McLarty prepared question naires and ^-tested questions with their colleagues; they identified the panel of experts, built a project Web site, collected and undertook the statistical analysis of gathered data, and produced the docu ments after each round. In effect, they provided the leadership for the consensus statement project. The remainder of the authors served as an advisory committee to develop all aspects of the question naire, review results, change or develop new ques tions for each round based on the available data, and contribute to and edit the manuscript. Materials and Methods The Delphi Technique An interactive technique known as the Delphi method is one systematic approach to maximize areas of agreement and mini mize the areas of disagreement regarding fundamental beliefs or assumptions regarding the role of asbestos exposure and how it affects respiratory health. Consensus among experts is a central assumption of Delphi methodology. This approach is employed for problems that are difficult to solve with conventional techniques.18-23 The Delphi method helps structure communication in a way that allows a group of individuals to deal with a complex problem by identifying consensus. It is a systematic process that can be clearly documented and involves a series of questions designed by a monitor group. The questions can be sent by e-mail in several rounds to a respondent group of experts who remain anonymous from one another. The anonymity of answers allows Delphi participants to express their personal views without face-to-face peer pressure. This method is particularly useful for topics on which there are strong differences of opinion or when high levels of uncertainty are present. After each round, the results are summarized and assessed, then used to develop a questionnaire for the next round at which time ah participants are asked to weigh in again. This forces experts to consider group opinion. The assessment document and revised questionnaire with supporting evidence (if available) is then sent out again to all who responded. A Delphi survey is considered complete when a convergence of opinion occurs or when a point of diminishing returns is reached. The reliability of the Delphi method depends largely on the selection of panel members, the size of the group, and the number of rounds.18 In the Delphi process utilized in this study, we first identified members of an international expert panel in an unbiased manner, described later. Key issues in asbestos-related diseases were then collected and reviewed for content and style by the American College of Chest Physicians (ACCP) Occupational and Environ mental NetWork steering committee. Key issues identified by the committee were then presented as a survey to the expert panel through e-mail or internet Web pages. A total of 32 statements were evaluated by the expert panel. Each statement was ranked on a Likert scale by each panel member. An 11-category scale ranged from 0 (strong disagreement) through 10 (strong agree ment), with a score of 5 indicating no opinion or not enough information to judge. A panel member was given the option of not weighing in on an issue if that topic was outside his or her respective area of expertise. Also, panelists were encouraged to supply references and other information in support of their opinion for each question. Results were compiled for each question and a quantitative measure of consensus (described in the next section) applied. The results were then distributed to the expert panelists and the ACCP steering committee. All informa tion was maintained on the Web site developed for this protocol (http://www.sh.lsuhsc.edu/medicine/delphi/). The issues for which consensus of opinion were not reached were returned to the expert panelists, this time with the compiled results and supportive evidence. This process was repeated for three rounds. Some questions were modified for clarity in the second round, and some new questions were added after the first round. This proposal was submitted to and approved by the Louisiana State University School of Medicine Institutional Review Board. Statistical Definition of Consensus Various methods of consensus have been utilized in other Delphi studies, including one concerning pulmonary disease.24 However, many of the methods are not statistically rigorous. We developed a statistically based definition of consensus and degree of consensus, based on probabilities (p value) and interquartile range (IQR). The Wilcoxon signed rank test was used to test the null hypothesis that there was an even distribution of scores throughout the range. Four degrees of consensus were defined: very good, p < 0.05 and IQR < 2; good, p < 0.05 and IQR < 3; some, p < 0.05 and IQR < 4; and none, p > 0.05 or IQR > 4. www.chestjournal.org CHEST/135/6/JUNE, 2009 Downloaded from www.chestjournal.org by guest on August 25, 2009 Copyright 2009 American College of Chest Physicians 1621 Expert Panel Formation Identification and selection of the expert group is critical to a consensus document because the experts' judgments form the basis of conclusions. The choices of expert participants for the Delphi inquiries were vetted extensively by the ACCP steering committee. An attempt was made to identify, in an unbiased manner, individuals with significant numbers of recent first author publi cations (reviews or peer-reviewed manuscripts only) pertaining to asbestos-related disease. A PubMed search was conducted of publications related to asbestos disease for the approximate 10-year period from January 1, 1991, through May 15, 2002 (the initial date of the search). Only clinically relevant publications pertaining to asbestos were retrieved. Animal studies were excluded. The search yielded 1,106 references. We sorted this list by first author and counted the number of publications for each first author. Ninety-five individuals were the first author of > 3 publications (some had as many as 13 publications). These 95 individuals represented a diverse panel from different countries and institutions. One author was known to be deceased, limiting the cohort of eligible experts to 94. We invited 71 members from the expert pool with known e-mail addresses to participate. Although we concede a potential for bias in excluding those without e-mail access (such individuals without e-mail may be the most or the least knowledgeable), we considered this the most practical means of communicating with our international panel of experts. Participation was anonymous; none of the panelists knew the identity of the other panelists. Questionnaire Development A major task in planning the use of the Delphi method in assessing the health effects of asbestos was to identify and select issues that could benefit from formal consensus of expert judg ments. Issue identification and selection was based on a broad review with a goal of addressing a comprehensive slate of topics. We emphasized selection of a broad subject, rather than begin ning with a limited list and defending the omission of issues after the fact. We invited comments from members of the ACCP Occupational and Environmental NetWork Steering Commit tee and the Workers' Compensation Board of Alberta, Canada, individuals with expert knowledge about the health problems of asbestos. After a reasonable assurance that the list of issues was complete, we identified 25 statements later incorporated into the panel survey. After the first round, it was apparent that three questions needed clarification, and seven new statements were added in response to expert panel and steering committee suggestions. Six statements were adapted directly from the 1986 ATS diagnostic guidelines document.1 A complete list of the 32 statements considered for consensus appears in Tables 1, 2, and 3. Results Figure 1 illustrates the Delphi process for one opinion statement for which consensus was reached after three Delphi rounds. In this case, the expert consensus was to disagree with the statement. Over all, the results showed some degree of consensus on 23 statements. Seven of the 25 questions achieved consensus in the first round. Seven new statements were added after round 1, and three were modified for clarity. Twelve of the remaining 25 questions achieved consensus in the second round, and 4 of the remaining 13 questions in the third round reached consensus. There was no consensus reached for nine statements. Tables 1 and 2 contain the 17 statements for which consensus with agreement was reached and the 6 statements of consensus with disagreement by the expert panel, respectively. Table 3 lists the nine statements for which no consensus was achieved. A variable number of experts participated in each round and each statement, as follows: 34 experts voted in round 1; 29 experts voted in round 2; and 24 experts voted in round 3. Within each round, experts were given the option of not evaluating some state ment, although most voted on all questions. Discussion The expert panel agreed with the provisions of the 1986 ATS position statement on the diagnosis of asbestos-related disease1 with good or very good consensus. This project was underway prior to the publication of the second 2004 ATS statement, Diagnosis and Initial Management of Nonmalignant Diseases of Asbestos.17 There are several aspects of these reports that invite comparison with the Delphi process findings. The authors of the second ATS statement17 comment that "a profusion of irregular opacities at the level of 0/1 is the boundary between normal and abnormal in the evaluation of the film, although the measure of profusion is continuous and there is no clear demarcation between 0/1 and 1/0. When radiographic or lung function abnormalities are indeterminate, HRCT [high-resolution CT]scanning is often useful in revealing characteristic paren chymal abnormalities." In this report, experts agreed that in the setting of a category 1/0 radiograph, the high-resolution CT (HRCT) scan would increase the specificity of these radiographic findings. In both this report and the second ATS statement, there is recognition that asbestosis can develop without im pairment. Although the authors of the second ATS state ment17 characterized the role of asbestos as a cause of airways obstruction as controversial, they provide evidence to show that asbestos exposure has long been associated with obstructive physiologic abnor mality. The experts in this report were unable to reach a consensus when asked to agree or to disagree with the statement "A decline in small airway flow rates in a nonsmoker can be attributed to asbestos exposure." In fact, the experts seem evenly divided on the issue and the results did not change substan tially from round to round. This resistance to change due to the Delphi process may be indicative of firmly 1622 Consensus Statement Downloaded from www.chestjournal.org by guest on August 25, 2009 Copyright 2009 American College of Chest Physicians Table 1--Consensus Statements Showing Agreement Statement No. Consensus Statement Median IQR p Value 1 Workers with asbestos exposure and pleural plaques or diffuse pleural thickening 9.5 3 0.0001 (in the absence of fibrosis) are at increased risk of mesothelioma 2 Asbestos exposure can cause diffuse pleural thickening 10 0 0.0001 3 Asbestos exposure can cause pleural plaques 4* ... a reliable history of exposure 10 0 0.0001 10 1 0.0001 5* ... an appropriate time interval between exposure and detection 9 2 0.0001 6t .... chest roentgenographic evidence of "s," "t," "u" small irregular 6.5 4 0.0112 opacifications of a profusion of 1/1 or greater 7t ... a restrictive pattern of lung impairment with a FVC below the lower limit of 7 3 0.0474 normal 8t ... a diffusing capacity below the lower limit of normal 7 3 0.0074 9t . . . bilateral late or pan inspiratory crackles at the posterior lung bases not 6 3 0.0471 cleared by cough 10 A history of asbestos exposure of sufficient duration, dose and latency is likely 9 2 0.0001 the cause of interstitial fibrosis in the absence of other explanations 11 Asbestos exposure causes other neoplasms in addition to lung cancer and 7 3 0.0114 mesothelioma 12 Identification of asbestos fibers in lung specimens is integral to the histological 8 4 0.0175 diagnosis of asbestosis 13{ . . . chest radiographic changes of profusion 1/1 small irregular opacities or 8 3 0.0001 greater or high-resolution CT scanning images in the prone position at lung bases indicating interstitial fibrosis are of value in detecting asbestosis. 14{ . . . chest radiographic changes of a profusion level 1/0 small irregular opacities 7 4 0.0091 are a good screening tool, but lack specificity for an accurate diagnosis of asbestosis. HRCT scanning should be performed to increase the specificity of these chest radiographic findings 15 In an asbestos-exposed worker without asbestosis and with lung cancer, the 8 1 0.0037 recognition of asbestosis among coworkers with similar exposures is sufficient to attribute the worker's lung cancer to asbestos exposure 16 Compared to the chest radiograph, an HRCT scan is a more sensitive method 9 2 0.0001 for detecting asbestos-related pleural and parenchymal disease 17 Workers who have significant asbestos exposure (but who do not have asbestosis) 9 2 0.0001 are at increased risk of bronchogenic carcinoma *Based on 1986 ATS guidelines.1 This statement was preceded by "In the absence of pathologic examination of lung tissue, the diagnosis of asbestosis is a judgment based on a careful consideration of all relevant clinical findings. In our opinion, it is necessary that there be." jThis statement was preceded by "These clinical criteria are of recognized value." {This statement was preceded by "With a reliable history of exposure and an appropriate time interval between exposure and detection [and in] the absence of pathologic examination of lung tissue." held diverse opinions. Further, the probability of no consensus was large for this question (p = 0.76). In the second ATS statement,17 the authors report that the presence of plaques is associated with a greater risk of lung cancer compared to individuals with similar exposure without such radiographic findings. In this report, there is strong disagreement with that conclusion. Weiss25 reviewed this issue in Table 2--Consensus Statements Showing Disagreement Statement No. 1 2 3 4 5 6 Consensus Statement Chest radiographs are a sensitive method to diagnose interstitial disease attributable to asbestos exposure Chest radiographs are a sensitive method to measure pleural abnormalities attributable to asbestos exposure Pleural plaques alter lung function to a clinically significant degree Workers with asbestos-induced pleural abnormalities are at increased risk for lung cancer compared to workers with similar exposures without these pleural abnormalities Asbestos exposure (in the absence of interstitial fibrosis) leads to COPD A decline in small airway flow rates in a smoker can be attributed to asbestos exposure Median IQR p Value 2 3 0.0009 3 2 0.0001 2 3 0.0003 1 2 0.001 3 4 0.0001 2 3 0.0001 www.chestjournal.org CHEST/135/6/ JUNE, 2009 Downloaded from www.chestjournal.org by guest on August 25, 2009 Copyright 2009 American College of Chest Physicians 1623 Table 3--Statements Without Expert Panel Consensus Statement No. Statement Median IQR p Value 1 A heavy asbestos exposure (sufficient to cause asbestosis) with sufficient latency is 2.5 7 0.0994 necessary to establish asbestos exposure as causative for lung cancer (clarified from round 1) 2 The extent of asbestos exposure correlates with the presence and extent of 6 4 0.325 pleural abnormalities 3 A reasonable scheme can be developed to apportion the individual attributability 5 5 0.5907 of smoking and exposure in a cigarette smoking asbestos-exposed worker with lung cancer 4 A decline in small airway flow rates in a nonsmoker can be attributed to asbestos 6 6.5 0.7637 exposure 5 BAL is a technique for accurately establishing lung fiber burden 5 4 0.252 6 CT scanning of the chest should be used to screen populations at risk for 5 3 0.2445 asbestos-related diseases 7 There should be initiatives to develop protocols to attempt therapy for asbestosis 5 5 0.0209 8 Nonsmoking workers with significant asbestos exposure (without asbestosis) have 7.5 4 0.0609 at least double the risk of bronchogenic carcinoma compared to nonsmoking workers with low-level exposure 9 Workers who smoke cigarettes and have significant asbestos exposure (without 9 5 0.0031 asbestosis) have at least double the risk of bronchogenic carcinoma compared to nonexposed smokers detail and concluded that lung cancer risk is not elevated among individuals with asbestos-related pleural plaques in the absence of asbestosis. Issues that remain contentious generally fit into the following several categories: the value of HRCT scanning for screening; the feasibility of protocols for therapy of asbestosis; pleural changes related to asbestos exposure; and the issue of attributable risk for lung cancer due to smoking or asbestos exposure. Of these statements, only one is addressed in the second ATS report. Data were cited showing that large studies of workers with pleural plaques had approximately a 5% mean decline in FVC compared to asbestos workers without pleural plaques. In this report, the experts concluded that the presence of pleural plaques did not decrease lung function to a significant extent. We suggest that the conclusions reported in Ta bles 1 and 2 are reasonable and can form a starting point of agreement on the issues regarding the health effects of asbestos exposure. We suggest that there is uniform agreement with the conclusions presented in the first ATS statement1 regarding the diagnosis of nonmalignant respiratory disease attrib utable to asbestos exposure. We suggest that issues regarding asbestos-related pulmonary disease that failed to achieve consensus by the expert panel include the following: the value of HRCT scanning for screening; the feasibility of protocols for therapy for asbestosis; pleural changes related to asbestos exposure; the recognition that a decline in small airway expiratory flow rates in a nonsmoker without asbestosis or COPD cannot be reliably attributed to asbestos exposure; and the issue of attributable risk for lung cancer due to smoking or asbestos exposure. In our group of questions without consensus, a median score at or near the midpoint of the Likert scale, in this instance a score of 5, implies that the experts were unable to either agree or disagree, perhaps in some instances due to the recognition that insufficient information was avail able to make an informed decision. Of particular interest is the failure of experts to agree on whether asbestos exposure or asbestosis is the cause of the increased risk of lung cancer in asbestos workers. To begin, the facts that most asbestos-associated cancers occur in those who are cigarette smokers, that smoking represents the stron gest identifiable lung cancer risk among many oth ers, and the fact that lung cancer is a relatively common malignancy in industrialized societies make an analysis of the relationship between smoking and asbestos exposure complex.26 The arguments were initially framed by Mereweather,27 who showed that lung cancer occurred in 35 of 235 of deaths in which the persons were autopsied (13.2%) where asbestosis was identified. In 1955, the first mortality study of a cohort of asbestos-exposed workers showed that among 105 deaths, lung cancer was found in 18 instances, 15 times in association with asbestosis. In the three instances without asbestosis, the latency periods were 2, 12, and 11 years.28 Conclusions from these and other reports were crystallized by Browne,29 who reported there was sufficient evi dence to justify the hypothesis that lung cancer in asbestos-exposed workers was due to asbestosis and 1624 Consensus Statement Downloaded from www.chestjournal.org by guest on August 25, 2009 Copyright 2009 American College of Chest Physicians American College of Chest Physicians Consensus Statement on the Respiratory Health Effects of Asbestos Daniel E. Banks, Runhua Shi, Jerry McLarty, Clayton T. Cowl, Dorsett Smith, Susan M. Tarlo, Feroza Daroowalla, John Balmes and Michael Baumann Chest 2009;135; 1619-1627 DOI 10.1378/chest.08-1345 This information is current as of August 25, 2009 Updated Information & Services Updated Information and services, including high-resolution figures, can be found at: http://www.chestjournal.org/content/135/6/1619.full.html References Open Access Permissions & Licensing Reprints Email alerting service Images in PowerPoint format This article cites 27 articles, 13 of which can be accessed free at: http://www.chestjournal.org/content/135/6/1619.full. html#ref-list-1 Freely available online through CHEST open access option Information about reproducing this article in parts (figures, tables) or in its entirety can be found online at: http://www.chestjournal.org/site/misc/reprints.xhtml Information about ordering reprints can be found online: http://www.chestjournal.org/site/misc/reprints.xhtml Receive free email alerts when new articles cite this article. Sign up in the box at the top right corner of the online article. Figures that appear in CHEST articles can be downloaded for teaching purposes in PowerPoint slide format. See any online article figure for directions. Downloaded from www.chestjournal.org by guest on August 25, 2009 Copyright 2009 American College of Chest Physicians