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Howlett P, Gan J, Lesosky M, Feary J. Relationship between cumulative silica exposure and silicosis: a systematic review and dose-response meta-analysis. Thorax 2024; 79:934-942. [PMID: 39107111 DOI: 10.1136/thorax-2024-221447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Accepted: 05/17/2024] [Indexed: 08/09/2024]
Abstract
BACKGROUND Silicosis, a chronic respiratory disease caused by crystalline silica exposure, is a persistent global lung health issue. No systematic review of the relationship between cumulative respirable crystalline silica (RCS) exposure and silicosis exists. UK exposure limits are currently under review. We therefore performed a systematic review and dose-response meta-analysis of this relationship. METHODS Web of Science, Medline and Embase were searched on 24 February 2023. Studies of radiographic, autopsy or death certificate silicosis, with an estimated average follow-up of over 20 years since first employment, were included. Cumulative silicosis risk methods were compared. The relative risks (RR) of silicosis at increasing cumulative exposures were calculated and used to estimate the absolute risk reduction (ARR). RESULTS Eight eligible studies, including 10 cohorts, contributed 8792 cases of silicosis among 65 977 participants. Substantial differences in cumulative risk estimates between methodologies exist. Using the same method, we observed higher cumulative silicosis risks among mining compared with non-mining cohorts. A reduction from 4 to 2 mg/m³-years in cumulative RCS exposure corresponded to substantial risk reductions among miners (RR 0.23 (95% CI 0.18 to 0.29, I2=92.9%) with an ARR of 323 (95% CI 298 to 344) per 1000) and non-miners (RR 0.55 (95% CI 0.36 to 0.83, I2=77.0%) with an ARR of 23 (95% CI 9 to 33) per 1000). CONCLUSION Despite significant heterogeneity, our findings support a reduction in permissible exposure limits from 0.1 mg/m3 to 0.05 mg/m³, particularly among mining populations. Further research is needed among non-miners as only two studies were eligible.
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Affiliation(s)
- Patrick Howlett
- National Heart and Lung Institute, Imperial College London, London, UK
| | - Jeffrey Gan
- National Heart and Lung Institute, Imperial College London, London, UK
| | - Maia Lesosky
- National Heart and Lung Institute, Imperial College London, London, UK
| | - Johanna Feary
- National Heart and Lung Institute, Imperial College London, London, UK
- Department of Occupational Lung Disease, Royal Brompton Hospital, London, UK
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J-P NA, SUSANTO AD, SAMOEDRO E, MANSYUR M, TUNGSAGUNWATTANA S, LERTROJANAPUNYA S, SUBHANNACHART P, SIRIRUTTANAPRUK S, DUMAVIBHAT N, ALGRANTI E, PARKER JE, HERING KG, KANAYAMA H, TAMURA T, KUSAKA Y, SUGANUMA N. Asian Intensive Reader of Pneumoconiosis program: examination for certification during 2008-2020. INDUSTRIAL HEALTH 2024; 62:143-152. [PMID: 37407488 PMCID: PMC10995673 DOI: 10.2486/indhealth.2023-0010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 06/27/2023] [Indexed: 07/07/2023]
Abstract
This study examined physicians' participation and performance in the examinations administered by the Asian Intensive Reader of Pneumoconiosis (AIR Pneumo) program from 2008 to 2020 and compared radiograph readings of physicians who passed with those who failed the examinations. Demography of the participants, participation trends, pass/fail rates, and proficiency scores were summarized; differences in reading the radiographs for pneumoconiosis of physicians who passed the examinations and those who failed were evaluated. By December 2020, 555 physicians from 20 countries had taken certification examinations; the number of participants increased in recent years. Reported background specialty training and work experience varied widely. Passing rate and mean proficiency score for participants who passed were 83.4% and 77.6 ± 9.4 in certification, and 76.8% and 88.1 ± 4.5 in recertification examinations. Compared with physicians who passed the examinations, physicians who failed tended to classify test radiographs as positive for pneumoconiosis and read a higher profusion; they likely missed large opacities and pleural plaques and had a lower accuracy in recognizing the shape of small opacities. Findings suggest that physicians who failed the examination tend to over-diagnose radiographs as positive for pneumoconiosis with higher profusion and have difficulty in correctly identifying small opacity shape.
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Affiliation(s)
- Naw Awn J-P
- Department of Environmental Medicine, Kochi Medical School,
Kochi University, Japan
| | - Agus Dwi SUSANTO
- Department of Pulmonology and Respiratory Medicine, Faculty
of Medicine, Universitas Indonesia, Persahabatan Hospital, Indonesia
| | - Erlang SAMOEDRO
- Department of Pulmonology and Respiratory Medicine, Faculty
of Medicine, Universitas Indonesia, Persahabatan Hospital, Indonesia
| | - Muchtaruddin MANSYUR
- Department of Community Medicine, Faculty of Medicine,
Universitas Indonesia & Southeast Asian Ministers of Education Regional Centre for
Food and Nutrition (SEAMEO RECFON), Indonesia
| | - Sutarat TUNGSAGUNWATTANA
- Department of Radiology, Central Chest Institute of Thailand,
Department of Medical Services, Ministry of Public Health, Thailand
| | - Saijai LERTROJANAPUNYA
- Department of Radiology, Central Chest Institute of Thailand,
Department of Medical Services, Ministry of Public Health, Thailand
| | - Ponglada SUBHANNACHART
- Department of Radiology, Central Chest Institute of Thailand,
Department of Medical Services, Ministry of Public Health, Thailand
| | | | - Narongpon DUMAVIBHAT
- Department of Preventive and Social Medicine, Faculty of
Medicine Siriraj Hospital, Mahidol University, Thailand
| | | | - John E. PARKER
- Pulmonary and Critical Care Medicine, Robert C. Byrd Health
Sciences Center, School of Medicine, West Virginia University, USA
| | - Kurt G. HERING
- Klinikum-Westfalen−Miner’s Hospital
(Knappschaftskrankenhaus), Germany
| | - Hitomi KANAYAMA
- Division of Environmental Health, Department of
International Social and Health Sciences, Faculty of Medical Sciences, University of
Fukui, Japan
| | - Taro TAMURA
- Department of Environmental Medicine and Public Health,
Faculty of Medicine, Shimane University, Japan
| | - Yukinori KUSAKA
- Health Care Center, Shimane Prefectural Federation of
Agricultural Cooperatives for Health and Welfare (JA Shimane Koseiren), Japan
| | - Narufumi SUGANUMA
- Department of Environmental Medicine, Kochi Medical School,
Kochi University, Japan
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Peng YF, Zhang QS, Luo WG. The Clinical Usefulness of Mean Corpuscular Hemoglobin Concentration in Patients with Pneumoconiosis. Int J Gen Med 2023; 16:3171-3177. [PMID: 37533840 PMCID: PMC10391047 DOI: 10.2147/ijgm.s417962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 07/06/2023] [Indexed: 08/04/2023] Open
Abstract
Aim We investigated the clinical usefulness of mean corpuscular hemoglobin concentration (MCHC) in patients with pneumoconiosis. Methods We retrospectively investigated the medical records from 52 patients with pneumoconiosis, and erythrocyte parameters were analyzed in pneumoconiosis patients with different stages. Results Here, we found that the values of MCHC were significantly lower in III stage pneumoconiosis than those with I/II stage (p = 0.024), and there was no significantly difference in MCHC between smoking pneumoconiosis patients and non-smoking pneumoconiosis patients. A negatively correlation between MCHC and disease stage was observed in patients with pneumoconiosis (r = -0.298, p = 0.032). In multiple linear regression analysis, the MCHC was found to be independently associated with advanced pneumoconiosis in patients with pneumoconiosis (p=0.011). The results of logistic regression analysis indicated that decreased MCHC was an independent risk factor of advanced pneumoconiosis in patients with pneumoconiosis (OR: 0.936, CI95%: 0.877-0.999, p = 0.046). Receiver operating characteristic curve analysis showed that the optimal cutoff value of MCHC was 330 g/L to identify advanced pneumoconiosis with the area under the curve of 0.694 (CI95%:0.550-0.839, p = 0.018). Conclusion The decreased MCHC is associated with advanced pneumoconiosis, and MCHC may be used as a monitoring marker for follow-up of pneumoconiosis patients.
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Affiliation(s)
- You-Fan Peng
- Department of Respiratory and Critical Care Medicine, The Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, People’s Republic of China
| | - Qing-Song Zhang
- Department of Respiratory and Critical Care Medicine, The Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, People’s Republic of China
| | - Wei-Gui Luo
- Department of Respiratory and Critical Care Medicine, The Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, People’s Republic of China
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Wang H, Ye Q, Chen Y, Li T. Epidemiology of coal miners' pneumoconiosis and its social determinants: An ecological study from 1949 to 2021 in China. CHINESE MEDICAL JOURNAL PULMONARY AND CRITICAL CARE MEDICINE 2023; 1:46-55. [PMID: 39170871 PMCID: PMC11332845 DOI: 10.1016/j.pccm.2023.03.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Indexed: 08/23/2024]
Abstract
Background Pneumoconiosis is the most widely distributed occupational disease worldwide. China is currently the largest coal producer and consumer and the country with the most coal miners and cases of coal workers' pneumoconiosis (CWP). Despite more than 70 years of effort, the problem of CWP and silicosis remains serious. There is a lack of analysis of direct data on coal miners' pneumoconiosis from all over the country. This study aimed to describe the epidemiology of coal miners' pneumoconiosis and reveal some important clues regarding its social determinants. Methods The annual incidence rate, 20-year prevalence rate, and incidence rate of coal miners' pneumoconiosis per million tons in China from 1949 to 2021 were calculated by using the data of annual number of coal miners' pneumoconiosis diagnosed and reported from the coal mining and dressing industry, the number of coal miners, and the raw coal production, and the relationship between the incident cases of coal miners' pneumoconiosis and the death toll from coal mine safety accidents was analyzed using Pearson correlation analysis, with the aim of exploring the relationship between the incident cases of coal miners' pneumoconiosis and its social determinants with an ecological study. Results From 1949 to 2021, there have been more than 462,000 patients with coal miners' pneumoconiosis in China, showing double U-shaped distributions with an increasing trend, accounting for about 50.5% (462,000/915,000) of all diagnosed pneumoconiosis in China, while the incidencet rate of coal miners' pneumoconiosis presents a large W shaped distribution with three peaks over a time span of more than 50 years. From 1949 to 1986, there was a strong correlation between the incident cases of coal miners' pneumoconiosis and raw coal production, the number of coal miners, and the number of deaths from coal mine accidents (r = 0.849, P < 0.001; r = 0.817, P < 0.001; r = 0.697, P < 0.001, respectively), but there was no such correlation found from 1987 to 2006. It was estimated that the annual incidence rate of coal miners' pneumoconiosis in China from 2016 to 2020 was 3.4‰ (95% CI: 2.6-4.3‰), and the prevalence rate across the recent 20-year observation period was 4.8% (95% CI: 4.6-4.9%), both measured at the peak or around the peak over the 70 years. In particular, 1963, 1986, 2006, and 2009 were the four important turning points in time. Conclusion There was a sustained high level of incident cases of coal miners' pneumoconiosis with double U-shaped curve in China, which may be affected by a variety of social determinants and risk factors.
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Affiliation(s)
- Huanqiang Wang
- Department of Occupational Respiratory Diseases, National Institute of Occupational Health and Poison Control, Chinese Center for Disease Control and Prevention, Beijing 100050, China
| | - Qiao Ye
- Department of Occupational Medicine and Toxicology, Clinical Center for Interstitial Lung Diseases, Beijing Institute of Respiratory Medicine, Beijing Chao-Yang Hospital Capital Medical University, Beijing 100020, China
| | - Yun Chen
- Department of Occupational Respiratory Diseases, National Institute of Occupational Health and Poison Control, Chinese Center for Disease Control and Prevention, Beijing 100050, China
| | - Tao Li
- Department of Occupational Respiratory Diseases, National Institute of Occupational Health and Poison Control, Chinese Center for Disease Control and Prevention, Beijing 100050, China
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Peng YF, Deng JH, Huang XY, Zhang QS. Serum Bilirubin Levels and Disease Severity in Patients with Pneumoconiosis. Can Respir J 2023; 2023:5642040. [PMID: 36960314 PMCID: PMC10030211 DOI: 10.1155/2023/5642040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 01/19/2023] [Accepted: 02/16/2023] [Indexed: 03/17/2023] Open
Abstract
Aim To investigate the association between serum bilirubin and disease severity in patients with pneumoconiosis. Methods The study comprised 45 patients with pneumoconiosis retrospectively; all pneumoconiosis patients were classified into I, II, and III stage according to the radiological severity. Results Serum direct bilirubin levels were significantly lower in III stage pneumoconiosis patients than those in I/II stage (p = 0.012) but not serum indirect bilirubin. Serum direct bilirubin was negatively correlated with radiological severity in patients with pneumoconiosis (r = -0.320; p = 0.032); by multiple linear-regression analysis, we observed that serum direct bilirubin levels had independent association with radiological severity in patients with pneumoconiosis (beta = -0.459; p = 0.005). Conclusions Serum direct bilirubin levels are negatively associated with disease severity in patients with pneumoconiosis.
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Affiliation(s)
- You-Fan Peng
- Department of Respiratory and Critical Care Medicine, The Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, China
| | - Jun-Hua Deng
- Department of Respiratory and Critical Care Medicine, The Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, China
| | - Xiao-Ying Huang
- Department of Respiratory and Critical Care Medicine, The Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, China
| | - Qing-Song Zhang
- Department of Respiratory and Critical Care Medicine, The Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, China
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6
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Sex-Related Differences in the Risk of Silicosis Among Chinese Pottery Workers: A Cohort Study. J Occup Environ Med 2021; 63:74-79. [PMID: 33122539 DOI: 10.1097/jom.0000000000002068] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To investigate the effect of sex on the risk of silicosis and to explore any interaction between cigarette smoking and sex in the development of silicosis. METHODS The cohort was selected from eight Chinese pottery factories. Diagnoses of silicosis were based on 1986 Chinese pneumoconiosis Roentgen diagnostic criteria. Data on cigarette smoking were collected by face-to-face interviews in 1989 and 2003. RESULTS Eight thousand eight hundred and eighty seven dust-exposed workers were included. Men had a 77% higher incidence of silicosis than women. At lower pack-years of smoking, men were 72% more at risk than women. The latency period was found to be longest in female never-smokers and shortest in female ever-smokers. CONCLUSIONS Men had a higher risk of developing silicosis than women. Cigarette smoking increased the risk in both sexes, more so in women.
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7
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Wang D, Zhou M, Liu Y, Ma J, Yang M, Shi T, Chen W. Comparison of Risk of Silicosis in Metal Mines and Pottery Factories. Chest 2020; 158:1050-1059. [DOI: 10.1016/j.chest.2020.03.054] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 03/16/2020] [Accepted: 03/19/2020] [Indexed: 11/27/2022] Open
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8
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Halldin CN, Hale JM, Weissman DN, Attfield MD, Parker JE, Petsonk EL, Cohen RA, Markle T, Blackley DJ, Wolfe AL, Tallaksen RJ, Laney AS. The National Institute for Occupational Safety and Health B Reader Certification Program-An Update Report (1987 to 2018) and Future Directions. J Occup Environ Med 2019; 61:1045-1051. [PMID: 31626070 PMCID: PMC7189962 DOI: 10.1097/jom.0000000000001735] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
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.
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Affiliation(s)
- Cara N Halldin
- Respiratory Health Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention (Dr Halldin, Ms Hale, Dr Weissman, Dr Attfield, Dr Petsonk, Dr Cohen, Mr Markle, Dr Blackley, Ms Wolfe, Dr Tallaksen, Dr Laney); Department of Environmental and Occupational Health Sciences, School of Public Health, University of Illinois, Chicago, Illinois (Dr Cohen); Departments of Radiology, Medical Education, and Internal Medicine, School of Medicine (Dr Parker, Dr Petsonk, Dr Tallaksen), West Virginia University, Morgantown, West Virginia
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9
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Zhao J, Li J, Zhao C. Prevalence of pneumoconiosis among young adults aged 24-44 years in a heavily industrialized province of China. J Occup Health 2019; 61:73-81. [PMID: 30698344 PMCID: PMC6499438 DOI: 10.1002/1348-9585.12029] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 07/15/2018] [Accepted: 08/20/2018] [Indexed: 11/08/2022] Open
Abstract
Objectives The purposes of this study were to clarify (i) the prevalence of pneumoconiosis among young adults and (ii) the factors associated with pneumoconiosis among young adults to explore targeted solution for control of pneumoconiosis among young adults (aged 24‐44 years). Methods The new cases diagnosed from 2001 to 2015 (extracted from the National Occupational Disease and Occupational Health Information Monitoring System) were involved in this research, including information of employer, patient's name, date of birth, gender, date of diagnosis, first year of dust exposure, duration of exposure, aggregation etc Results A total of 1519 pneumoconiosis cases were diagnosed among young adults (21.6% of overall cases). Silicosis was the most common type with acute process of disease. Compared with overall cases, the young patients had shorter duration of exposure, more stage II/III cases and higher aggravation rate; and were even more concentrated in small and medium enterprises where more migrant workers were employed and insufficient protective measures were used. Without further regulation, the prevalence of pneumoconiosis among young adults would bring not only disease suffering for 3000 individuals and their families, but also an annual economic loss up to 180 million yuan for Hebei province till 2025. Conclusions As a typical heavily industrialized province of China, Hebei has severe situation on pneumoconiosis among young adults. Special attention and effort on silica‐contacting industries, small and medium enterprises, and migrant workers should be focused in future occupational supervision and regulation among young adults.
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Affiliation(s)
- Jun‐Qin Zhao
- Hebei Provincial Center for Disease Control and PreventionShijiazhuangChina
| | - Jian‐Guo Li
- Hebei Provincial Center for Disease Control and PreventionShijiazhuangChina
| | - Chun‐Xiang Zhao
- Hebei Provincial Center for Disease Control and PreventionShijiazhuangChina
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Cummings KJ, Johns DO, Mazurek JM, Hearl FJ, Weissman DN. NIOSH's Respiratory Health Division: 50 years of science and service. ARCHIVES OF ENVIRONMENTAL & OCCUPATIONAL HEALTH 2019; 74:15-29. [PMID: 30501580 PMCID: PMC6490691 DOI: 10.1080/19338244.2018.1532387] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The year 2017 marked the 50th anniversary of NIOSH's Respiratory Health Division (RHD). RHD began in 1967 as the Appalachian Laboratory for Occupational Respiratory Diseases (ALFORD), with a focus on coal workers' pneumoconiosis. ALFORD became part of NIOSH in 1971 and added activities to address work-related respiratory disease more generally. Health hazard evaluations played an important role in understanding novel respiratory hazards such as nylon flock, diacetyl, and indium-tin oxide. Epidemiologic and laboratory studies addressed many respiratory hazards, including coal mine dust, silica, asbestos, cotton dust, beryllium, diesel exhaust, and dampness and mold. Surveillance activities tracked the burden of diseases and enhanced the quality of spirometry and chest radiography used to screen workers. RHD's efforts to improve scientific understanding, inform strategies for prevention, and disseminate knowledge remain important now and for the future.
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Affiliation(s)
- Kristin J. Cummings
- Respiratory Health Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
| | - Doug O. Johns
- Respiratory Health Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
| | - Jacek M. Mazurek
- Respiratory Health Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
| | - Frank J. Hearl
- Office of the Director, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Washington, DC, USA
| | - David N. Weissman
- Respiratory Health Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
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11
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Keil AP, Richardson DB, Westreich D, Steenland K. Estimating the Impact of Changes to Occupational Standards for Silica Exposure on Lung Cancer Mortality. Epidemiology 2018; 29:658-665. [PMID: 29870429 PMCID: PMC6066423 DOI: 10.1097/ede.0000000000000867] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Respiratory exposure to silica is associated with the risk of death owing to malignant and nonmalignant disease. 2.3 million US workers are exposed to silica. Occupational exposure limits for silica are derived from a number of lines of evidence, including observational studies. Observational studies may be subject to healthy worker survivor bias, which could result in underestimates of silica's impact on worker mortality and, in turn, bias risk estimates for occupational exposure limits. METHODS Using data on 65,999 workers pooled across multiple industries, we estimate the impacts of several hypothetical occupational exposure limits on silica exposure on lung cancer and all-cause mortality. We use the parametric g-formula, which can account for healthy worker survivor bias. RESULTS Assuming we could eliminate occupational exposure, we estimate that there would be 20.7 fewer deaths per 1,000 workers in our pooled study by age 80 (95% confidence interval = 14.5, 26.8), including 3.91 fewer deaths owing to lung cancer (95% CI = 1.53, 6.30). Less restrictive interventions demonstrated smaller but still substantial risk reductions. CONCLUSIONS Our results suggest that occupational exposure limits for silica can be further strengthened to reduce silica-associated mortality and illustrate how current risk analysis for occupational limits can be improved.
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Affiliation(s)
- Alexander P Keil
- From the Department of Epidemiology, University of North Carolina, Chapel Hill, NC
| | - David B Richardson
- From the Department of Epidemiology, University of North Carolina, Chapel Hill, NC
| | - Daniel Westreich
- From the Department of Epidemiology, University of North Carolina, Chapel Hill, NC
| | - Kyle Steenland
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA
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12
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Halldin CN, Blackley DJ, Petsonk EL, Laney AS. 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. Radiology 2017; 284:870-876. [PMID: 28430556 DOI: 10.1148/radiol.2017162437] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
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.
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Affiliation(s)
- Cara N Halldin
- From the Surveillance Branch, Respiratory Health Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1095 Willowdale Rd, Mail Stop HG900.2, Morgantown, WV 26505-2888
| | - David J Blackley
- From the Surveillance Branch, Respiratory Health Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1095 Willowdale Rd, Mail Stop HG900.2, Morgantown, WV 26505-2888
| | - Edward L Petsonk
- From the Surveillance Branch, Respiratory Health Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1095 Willowdale Rd, Mail Stop HG900.2, Morgantown, WV 26505-2888
| | - A Scott Laney
- From the Surveillance Branch, Respiratory Health Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1095 Willowdale Rd, Mail Stop HG900.2, Morgantown, WV 26505-2888
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Abstract
BACKGROUND The association between crystalline silica exposure and risk of heart disease mortality remains less clear. METHODS We investigated a cohort of 42,572 Chinese workers who were potentially exposed to crystalline silica and followed from 1960 to 2003. Cumulative silica exposure was estimated by linking a job-exposure matrix to each person's work history. Low-level silica exposure was defined as never having held a job with an exposure higher than 0.1 mg/m. We estimated hazard ratios (HRs) in exposure-response analyses using Cox proportional hazards model. RESULTS We identified 2846 deaths from heart disease during an average of 35 years follow-up. Positive exposure-response trends were observed for cumulative silica exposure associated with mortality from total heart disease (HRs for increasing quartiles of cumulative silica exposure compared with the unexposed group = 0.89, 1.09, 1.32, 2.10; P for linear trend < 0.001) and pulmonary heart disease (0.92, 1.39, 2.47, 5.46; P for linear trend < 0.001). These positive trends remained among workers with both high- and low-level silica exposure. There was also a positive trend for ischemic heart disease among workers with low-level exposure, with quartile HRs of 1.04, 1.13, 1.52, and 1.60 (P for linear trend < 0.001). CONCLUSION Low-level crystalline silica exposure was associated with increased mortality from heart disease, including pulmonary heart disease and ischemic heart disease, whereas high-level exposure mainly increased mortality from pulmonary heart disease. Current permissible exposure limits for crystalline silica in many countries may be insufficient to protect people from deaths due to heart disease.
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Xing J, Huang X, Yang L, Liu Y, Zhang H, Chen W. Comparison of High‐resolution Computerized Tomography with Film‐screen Radiography for the Evaluation of Opacity and the Recognition of Coal Workers' Pneumoconiosis. J Occup Health 2014; 56:301-8. [DOI: 10.1539/joh.13-0149-oa] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Jingcai Xing
- Key Laboratory of Environment and Health, Department of Occupational and Environmental HealthSchool of Public Health, Tongji Medical College, Huazhong University of Science and TechnologyChina
- Department of Respiratory of the General Hospital of Xishan Coal & Power GroupCo. Ltd.China
| | - Xiji Huang
- Key Laboratory of Environment and Health, Department of Occupational and Environmental HealthSchool of Public Health, Tongji Medical College, Huazhong University of Science and TechnologyChina
| | - Lijuan Yang
- Department of Radiology of the General Hospital of Xishan Coal & Power GroupCo. Ltd.China
| | - Yuewei Liu
- Key Laboratory of Environment and Health, Department of Occupational and Environmental HealthSchool of Public Health, Tongji Medical College, Huazhong University of Science and TechnologyChina
| | - Hai Zhang
- Key Laboratory of Environment and Health, Department of Occupational and Environmental HealthSchool of Public Health, Tongji Medical College, Huazhong University of Science and TechnologyChina
| | - Weihong Chen
- Key Laboratory of Environment and Health, Department of Occupational and Environmental HealthSchool of Public Health, Tongji Medical College, Huazhong University of Science and TechnologyChina
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15
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Xia Y, Liu J, Shi T, Xiang H, Bi Y. Prevalence of pneumoconiosis in Hubei, China from 2008 to 2013. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2014; 11:8612-21. [PMID: 25158135 PMCID: PMC4198980 DOI: 10.3390/ijerph110908612] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 08/14/2014] [Accepted: 08/15/2014] [Indexed: 11/21/2022]
Abstract
We have investigated newly reported pneumoconiosis cases in the province of Hubei, China from 2008 to 2013, to identify the major problems and challenges, and explore possible solutions for its prevention and control. We analyzed the data on new cases of pneumoconiosis from annual reports, including case distributions, patient ages, exposure duration, disease stages, and enterprise types. A total of 3665 new pneumoconiosis cases were reported between 2008 and 2013 in Hubei Province. Coal workers' pneumoconiosis and silicosis, which accounted for 97.19% of the total, were the most common types. The duration of exposure of 33.32% cases was less than 10 years. Most of the new pneumoconiosis cases worked in industries that produced coal, nonferrous metal, or building materials. About 42.46% of pneumoconiosis cases were from small and medium-sized enterprises. The proportion of cases with combined pneumoconiosis and tuberculosis was 6.6%, and the incidence of tuberculosis was highest in workers with silicosis. The current situation of pneumoconiosis in China is serious. Lack of attention to occupational health, inefficient surveillance, and weak occupational health services may have contributed to the increased new pneumoconiosis cases.
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Affiliation(s)
- Ying Xia
- School of Public Health, Wuhan University, Wuhan 430079, China.
| | - Jiafa Liu
- Hubei Center for Disease Control and Prevention, 6 Zhuodaoquan North Road, Wuhan 430071, China.
| | - Tingming Shi
- Hubei Center for Disease Control and Prevention, 6 Zhuodaoquan North Road, Wuhan 430071, China.
| | - Hao Xiang
- School of Public Health, Wuhan University, Wuhan 430079, China.
| | - Yongyi Bi
- School of Public Health, Wuhan University, Wuhan 430079, China.
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16
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Liu Y, Steenland K, Rong Y, Hnizdo E, Huang X, Zhang H, Shi T, Sun Y, Wu T, Chen W. Exposure-response analysis and risk assessment for lung cancer in relationship to silica exposure: a 44-year cohort study of 34,018 workers. Am J Epidemiol 2013; 178:1424-33. [PMID: 24043436 DOI: 10.1093/aje/kwt139] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Crystalline silica has been classified as a human carcinogen by the International Agency for Research on Cancer (Lyon, France); however, few previous studies have provided quantitative data on silica exposure, silicosis, and/or smoking. We investigated a cohort in China (in 1960-2003) of 34,018 workers without exposure to carcinogenic confounders. Cumulative silica exposure was estimated by linking a job-exposure matrix to work history. Cox proportional hazards model was used to conduct exposure-response analysis and risk assessment. During a mean 34.5-year follow-up, 546 lung cancer deaths were identified. Categorical analyses by quartiles of cumulative silica exposure (using a 25-year lag) yielded hazard ratios of 1.26, 1.54, 1.68, and 1.70, respectively, compared with the unexposed group. Monotonic exposure-response trends were observed among nonsilicotics (P for trend < 0.001). Analyses using splines showed similar trends. The joint effect of silica and smoking was more than additive and close to multiplicative. For workers exposed from ages 20 to 65 years at 0.1 mg/m(3) of silica exposure, the estimated excess lifetime risk (through age 75 years) was 0.51%. These findings confirm silica as a human carcinogen and suggest that current exposure limits in many countries might be insufficient to protect workers from lung cancer. They also indicate that smoking cessation could help reduce lung cancer risk for silica-exposed individuals.
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Park RM, Chen W. Silicosis exposure-response in a cohort of tin miners comparing alternate exposure metrics. Am J Ind Med 2013; 56:267-75. [PMID: 22996756 DOI: 10.1002/ajim.22115] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/10/2012] [Indexed: 11/09/2022]
Abstract
BACKGROUND.: The detailed lung radiographic response to silica exposure has not been described. In estimating the exposure-response relationship in silicosis with statistical models, the absence of baseline (unattributable) risk can disable relative-rate estimation or produce widely varying estimates. This obstructs identification of optimum exposure metrics and invalidates comparisons and meta-analyses, which assume a common background rate. METHODS.: A cohort of 3,000 Chinese tin miners with more than 1,000 cases of silicosis was analyzed for the period 1961-1994. Regular surveillance documented three stages of silicosis. To examine the exposure-response relationship, the intercept in relative-rate models was fixed to correspond to 1% of the observed silicosis rate. Exposure metrics for contributions in different time-windows were simultaneously evaluated, as were burden and cumulative burden metrics. RESULTS.: Silica exposures that most contributed to silicosis onset occurred in the period 5-10 years prior (excess annual rate per 10 mg-year/m(3) , ER = 0.158, 95% CI = 0.125-0.192, or 16% per year). During 10-20 year prior, the excess rate contribution was much smaller (ER = 0.048, 95% CI = 0.037-0.060) but larger again during 20-30 year prior to onset (ER = 0.112, 95% CI = 0.098-0.126). For advanced silicosis, all time periods contributed about equally to the rate of onset. CONCLUSIONS.: Reliable estimates of parameters were observed, demonstrating exposure contributions over time. Burden metrics with different half-lives suggested some reversibility for silicosis onset with a half-life of 20 years. Advanced silicosis was best predicted with a cumulative burden metric which was consistent with prior observations that previously deposited silica continues to cause pulmonary damage.
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Affiliation(s)
- Robert M Park
- Risk Evaluation Branch, National Institute for Occupational Safety and Health, Cincinnati, OH, USA.
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18
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Mao L, Laney AS, Wang ML, Sun X, Zhou S, Shi J, Shi H. Comparison of digital direct readout radiography with conventional film-screen radiography for the recognition of pneumoconiosis in dust-exposed Chinese workers. J Occup Health 2011; 53:320-6. [PMID: 21778659 DOI: 10.1539/joh.10-0076-oa] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVES Pneumoconiosis in China remains a disease with substantial public health significance. Diagnostic standards for the pneumoconioses are based on traditional film-screen radiography (FSR). However, FSR is increasingly being replaced with digital radiographic imaging, which has become the predominant technology available in Chinese clinical practice. To evaluate the applicability of digital direct readout radiography (DR) images in the recognition of pneumoconioses, we compared the profusion of small opacities and large opacities between FSR and DR radiographs. METHODS We enrolled 161 pneumoconioses patients and 31 dust-exposed workers during the course of the study, with FSR and DR images obtained from all participants. Each chest film was interpreted by five readers using the Chinese Diagnostic Criteria classification of radiographs of pneumoconiosis, as were DR images displayed on medical-grade computer monitors. RESULTS No statistically significant differences were observed when the data were analyzed by small opacity profusion subcategory except for 1/1. The overall intermodality agreement of small opacities was good, with a weighted kappa (κ) of 0.77. CONCLUSIONS DR images with soft copy display are equivalent with respect to image quality and the recognition and classification of small parenchymal lung opacities. Additionally, we observed likeness between modalities with respect to the classification of large opacities. Overall, our study findings demonstrate that in a population of Chinese workers with pneumoconiosis, direct readout digital systems are equivalent to traditional film-screen radiography in the recognition and classification of small pneumoconiotic opacities.
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Affiliation(s)
- Ling Mao
- Department of Pneumoconiosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, China.
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Yu P, Xu H, Zhu Y, Yang C, Sun X, Zhao J. An automatic computer-aided detection scheme for pneumoconiosis on digital chest radiographs. J Digit Imaging 2011; 24:382-93. [PMID: 20174852 PMCID: PMC3092047 DOI: 10.1007/s10278-010-9276-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
This paper presents an automatic computer-aided detection scheme on digital chest radiographs to detect pneumoconiosis. Firstly, the lung fields are segmented from a digital chest X-ray image by using the active shape model method. Then, the lung fields are subdivided into six non-overlapping regions, according to Chinese diagnosis criteria of pneumoconiosis. The multi-scale difference filter bank is applied to the chest image to enhance the details of the small opacities, and the texture features are calculated from each region of the original and the processed images, respectively. After extracting the most relevant ones from the feature sets, support vector machine classifiers are utilized to separate the samples into the normal and the abnormal sets. Finally, the final classification is performed by the chest-based report-out and the classification probability values of six regions. Experiments are conducted on randomly selected images from our chest database. Both the training and the testing sets have 300 normal and 125 pneumoconiosis cases. In the training phase, training models and weighting factors for each region are derived. We evaluate the scheme using the full feature vectors or the selected feature vectors of the testing set. The results show that the classification performances are high. Compared with the previous methods, our fully automated scheme has a higher accuracy and a more convenient interaction. The scheme is very helpful to mass screening of pneumoconiosis in clinic.
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Affiliation(s)
- Peichun Yu
- Department of Biomedical Engineering, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, NO.800, Dongchuan Road, Shanghai, 200240 China
| | - Hao Xu
- Imaging Technologies Lab, GE Global Research, Shanghai, 201203 China
| | - Ying Zhu
- Department of Biomedical Engineering, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, NO.800, Dongchuan Road, Shanghai, 200240 China
| | - Chao Yang
- Imaging Technologies Lab, GE Global Research, Shanghai, 201203 China
| | - Xiwen Sun
- Shanghai Pulmonary Hospital, Shanghai, 200433 China
| | - Jun Zhao
- Department of Biomedical Engineering, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, NO.800, Dongchuan Road, Shanghai, 200240 China
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20
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Abejie BA, Wang X, Kales SN, Christiani DC. Patterns of pulmonary dysfunction in asbestos workers: a cross-sectional study. J Occup Med Toxicol 2010; 5:12. [PMID: 20525229 PMCID: PMC2890695 DOI: 10.1186/1745-6673-5-12] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Accepted: 06/03/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Restrictive patterns of pulmonary function abnormalities associated with asbestos exposure are well described. Studies are less consistent, however, regarding the association of asbestos inhalation with airway dysfunction and obstructive impairment. METHODS We compared pulmonary function test results between 277 chrysotile exposed workers (22% non-smokers) and 177 unexposed controls (50.3% non-smokers). Information on exposure and smoking were collected using a standardized questionnaire. Standardized spirometric and DCLO Measurement methods were utilized. CXRs were read based on ILO pneumoconiosis guidelines. RESULTS Asbestos exposed subjects had significantly reduced FVC, FEV1, FEV1/FVC and DLCO. Restricting the analysis to non-smokers, asbestos workers still had about 3% lower FEV1/FVC ratio than controls, but this difference did not reach statistical significance. Among exposed workers, the presence of radiographic evidence of asbestosis further lowered FVC and DLCO but not FEV1/FVC compared to asbestos exposure without radiographic asbestosis. Additionally, smoking asbestos workers had significantly lower DLCO compared to non-smoking workers. CONCLUSION Asbestos exposure, especially when radiographic evidence of interstitial fibrosis from asbestosis is present, leads to significant decreases in FVC, FEV1 and the DLCO. However, asbestos exposure alone is not significantly associated with a reduction of the FEV1/FVC. Smoking-asbestos workers had significantly lower DLCO than their non-smoking counterparts. Whether asbestos interacts with smoking additively or synergistically on DLCO needs further investigation. Similarly, further studies are needed to assess the progression and clinical significance of asbestos induced airway dysfunction.
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Affiliation(s)
- Belayneh A Abejie
- University of California San Francisco School of Medicine, Fresno Medical Education Program, Fresno, CA, USA
| | - Xiaorong Wang
- School of Public Health and Primary Care, The Chinese University of Hong Kong, SAR, China
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Chen W, Yang J, Chen J, Bruch J. Exposures to silica mixed dust and cohort mortality study in tin mines: exposure-response analysis and risk assessment of lung cancer. Am J Ind Med 2006; 49:67-76. [PMID: 16362950 DOI: 10.1002/ajim.20248] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Mineral dusts that contain crystalline silica have been associated directly or indirectly with the development of pneumoconiosis or silicosis, non-malignant respiratory diseases, lung cancer, and other diseases. The health impacts on workers with silica mixed dust exposure in tin mines and dose-response relationships between cumulative dust exposure and the mortality from lung cancer are investigated. METHODS A cohort of 7,837 workers registered in the employment records in 4 Chinese tin mines between 1972 and 1974 was identified for this study and the mortality follow-up was traced through 1994. Of the cohort, the cause of death was ascertained for 1,061 (97%) of the 1,094 deceased workers. Standardized mortality ratios (SMRs) were calculated for all workers, non-exposed workers, and dust-exposed workers with different exposure levels, silicotics, and non-silicotics based on Chinese national rates. RESULTS The mortality from all causes in four tin mines was nearly the same as the national mortality. Malignant neoplasm, cerebrovascular disease, and cardiovascular disease accounted for 68.6% of all deaths. Mortality excess from lung cancer, liver cancer, all malignant diseases, and non-malignant respiratory diseases was observed among dust-exposed workers; a 50-fold excess of pneumoconiosis was observed. There was an upward trend for SMRs of lung cancer was noted from no exposure to low, medium, and high exposure levels (SMRs=1.29, 2.65, 2.66, 3.33). The shape of the exposure-response curve for risk of lung cancer at high exposure levels was inconsistent in these four mines. CONCLUSIONS The findings indicated a positive dose-response relation between exposure to cumulative dust and the mortality of lung cancer. High arsenic content in dust particles, together with crystalline silica, may play an important role in causing increased mortality from lung cancer.
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Affiliation(s)
- Weihong Chen
- Department of Occupational and Environmental Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
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22
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Henry DA. International Labor Office Classification System in the age of imaging: relevant or redundant. J Thorac Imaging 2002; 17:179-88. [PMID: 12082369 DOI: 10.1097/00005382-200207000-00002] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The 1980 International Labor Office International Classification of Radiographs of Pneumoconioses is a widely used epidemiologic tool with a storied past. This article reviews its development and examines its applications to occupational lung disease and the controversies generated in that process. The question of its relevancy to current imaging practices is discussed.
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Affiliation(s)
- Daniel A Henry
- American College of Radiology Committee (formerly Task Force) on the Pneumoconioses and Department of Radiology, Medical College of Virginia Hospitals, School of Medicine, Virginia Commonwealth University, Richmond, USA.
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Abstract
OBJECTIVES To evaluate the relation between occupational dust exposure and lung cancer in tin mines. This is an update of a previous study of miners with high exposure to dust at four tin mines in southern China. METHODS A nested case-control study of 130 male lung cancer cases and 627 controls was initiated from a cohort study of 7855 subjects employed at least 1 year between 1972 and 1974 in four tin mines in China. Three of the tin mines were in Dachang and one was in Limu. Cumulative total exposure to dust and cumulative exposure to arsenic were calculated for each person based on industrial hygiene records. Measurements of arsenic, polycyclic aromatic hydrocarbons (PAHs), and radon in the work sites were also evaluated. Odds ratios (ORs), standard statistic analysis and logistic regression were used for analyses. RESULTS Increased risk of lung cancer was related to cumulative exposure to dust, duration of exposure, cumulative exposure to arsenic, and tobacco smoking. The risk ratios for low, medium, and high cumulative exposure to dust were 2.1 (95% confidence interval (95% CI) 1.1 to 3.8), 1.7 (95% CI 0.9 to 3.1), and 2.8 (95% CI 1.6 to 5.0) respectively after adjustment for smoking. The risk for lung cancer among workers with short, medium, and long exposure to dust were 1.9 (95% CI 1.0 to 3.5), 2.3 (95% CI 1.3 to 4.1), and 2.3 (95% CI 1.2 to 4.2) respectively after adjusting for smoking. Several sets of risk factors for lung cancer were compared, and the best predictive model included tobacco smoking (OR=1.6, 95% CI 1.1 to 2.4) and cumulative exposure to arsenic (ORs for different groups from low to high exposure were 2.1 (95% CI 1.1 to 3.9); 2.1 (95% CI 1.1 to 3.9); 1.8 (95% CI 1.0 to 3.6); and 3.6 (95% CI 1.8 5 to 7.3)). No excess of lung cancer was found among silicotic subjects in the Limu tin mine although there was a high prevalence of silicosis. Exposures to radon were low in the four tin mines and no carcinogenic PAHs were detected. CONCLUSIONS These findings provide little support for the hypothesis that respirable crystalline silica induces lung cancer. Ore dust in work sites acts as a carrier, the exposure to arsenic and tobacco smoking play a more important part in carcinogenesis of lung cancer in tin miners. Silicosis seems not to be related to the increased risk of lung cancer.
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Affiliation(s)
- W Chen
- Department of Labor Health and Occupational Diseases, Tongji Medical College, 13 Hang Kong Lu, Wuhan, Hubei, People's Republic of China.
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Wang XR, Yano E, Wang M, Wang Z, Christiani DC. Pulmonary function in long-term asbestos workers in China. J Occup Environ Med 2001; 43:623-9. [PMID: 11464393 DOI: 10.1097/00043764-200107000-00009] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The relationship of pulmonary function to exposure to asbestos and radiographic abnormalities has been controversial, especially when smoking is present as a confounder. The aim of the study was to provide further understanding on the radiographic-physiologic associations in nonsmoking and smoking asbestos workers. Radiographic asbestosis, pleural lesion, and pulmonary function were studied in 269 Chinese asbestos workers, with average exposure years of 23 for male workers and 18 for female workers. Their functional data were compared with those of 274 controls without exposure to dust. Although most of the male workers were smokers, none of the female workers smoked. In comparison with controls, asbestos workers had significantly lower lung volume and diffusing capacity, irrespective of gender. Female workers and smoking male workers had lower measurements of forced expiratory volume in 1 second and instantaneous forced expiratory flow at 50% and 25% of forced vital capacity. After adjustment for relevant covariates, asbestos exposure, asbestosis, and pleural abnormalities were associated with decreased parameters of pulmonary function, including lung volume, diffusing capacity, and airway flow. These data indicate that asbestos-related functional defects manifested by lung restriction and mild airway obstruction correlate with exposure to asbestos and with parenchymal and pleural abnormalities, independent of smoking.
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Affiliation(s)
- X R Wang
- Department of Environmental Health (Occupational Health Program), Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA
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Chen W, Zhuang Z, Attfield MD, Chen BT, Gao P, Harrison JC, Fu C, Chen JQ, Wallace WE. Exposure to silica and silicosis among tin miners in China: exposure-response analyses and risk assessment. Occup Environ Med 2001; 58:31-7. [PMID: 11119632 PMCID: PMC1740032 DOI: 10.1136/oem.58.1.31] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVES To investigate the risk of silicosis among tin miners and to investigate the relation between silicosis and cumulative exposure to dust (Chinese total dust and respirable crystalline silica dust). METHODS A cohort study of 3010 miners exposed to silica dust and employed for at least 1 year during 1960-5 in any of four Chinese tin mines was conducted. Historical total dust data from China were used to create a job exposure matrix for facility, job title, and calendar year. The total dust exposure data from China were converted to estimates of exposure to respirable crystalline silica for comparison with findings from other epidemiological studies of silicosis. Each worker's work history was abstracted from the complete employment records in mine files. Diagnoses of silicosis were based on 1986 Chinese pneumoconiosis Roentgen diagnostic criteria, which classified silicosis as stages I-III-similar to an International Labour Organisation (ILO) classification of 1/1 or greater. RESULTS There were 1015 (33.7%) miners identified with silicosis, who had a mean age of 48.3 years, with a mean of 21.3 years after first exposure (equivalent to 11.0 net years in a dusty job). Among those who had silicosis, 684 miners (67.4%) developed silicosis after exposure ended (a mean of 3.7 years after). The risk of silicosis was strongly related to cumulative exposure to silica dust and was well fitted by the Weibull distribution, with the risk of silicosis less than 0.1% when the Chinese measure of cumulative exposure to total dust (CTD) was under 10 mg/m(3)-years (or 0.36 mg/m(3)-years of respirable crystalline silica), increasing to 68.7% when CTD exposure was 150 mg/m(3)-years (or 5.4 mg/m(3)-years of respirable crystalline silica). Latency period was not correlated to the risk of silicosis or cumulative dose of exposure. This study predicts about a 36% cumulative risk of silicosis for a 45 year lifetime exposure to these tin mine dusts at the CTD exposure standard of 2 mg/m(3), and a 55% risk at 45 years exposure to the current United States Occupational Safety and Health Administration and Mine Safety and Health Administration standards of 0.1 mg/m(3) 100% respirable crystalline silica dust. CONCLUSIONS A clear exposure-response relation was detected for silicosis in Chinese tin miners. The study results were similar to most, but not all, findings from other large scale exposure-response studies.
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Affiliation(s)
- W Chen
- Department of Labor Health and Occupational Diseases, School of Public Health, Tonji Medical University, 13 Hang Kong Lu, Wuhan, Hubei, People's Republic of China.
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Wang XR, Christiani DC. Respiratory symptoms and functional status in workers exposed to silica, asbestos, and coal mine dusts. J Occup Environ Med 2000; 42:1076-84. [PMID: 11094786 DOI: 10.1097/00043764-200011000-00009] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This study aims to provide further understanding of physiologic and symptomatic changes and radiographic abnormalities due to exposure to silica, asbestos, and coal dusts. Questionnaires and pulmonary function tests were given to 220 silica, 277 asbestos, and 511 coal workers from three different industries in China. Posteroanterior chest radiographs were classified as stages 0, I, II, and III according to degree of parenchymal fibrosis. Significantly poorer pulmonary function and a higher prevalence of dyspnea and chronic cough were observed in workers with pneumoconiosis than those without, irrespective of dust type. Workers with stages II and III silicosis had worse pulmonary function and more common symptoms relative to workers with equivalent coal workers' pneumoconiosis or asbestosis. After adjusting for relevant confounders, reductions in the spirometric parameters and single breath diffusing capacity for carbon monoxide (DLCO) and the occurrence of respiratory symptoms were associated with increasing stage of silicosis, whereas lower DLCO and the occurrence of symptoms were associated with increasing stage of asbestosis and coal workers' pneumoconiosis. The study suggests that despite the differences in degree and pattern due to exposure to different fibrogenic dusts, respiratory impairments of all of the workers are associated with the presence and progression of parenchymal fibrosis and smoking.
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Affiliation(s)
- X R Wang
- Department of Environmental Health (Occupational Health Program), Harvard School of Public Health, Boston, MA 02115, USA
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27
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Hessel PA, Gamble JF, Gee JB, Gibbs G, Green FH, Morgan WK, Mossman BT. Silica, silicosis, and lung cancer: a response to a recent working group report. J Occup Environ Med 2000; 42:704-20. [PMID: 10914339 DOI: 10.1097/00043764-200007000-00005] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The relationship between crystalline silica and lung cancer has been the subject of many recent publications, conferences, and regulatory considerations. An influential, international body has determined that there was sufficient evidence to conclude that quartz and cristobalite are carcinogenic in humans. The present authors believe that the results of these studies are inconsistent and, when positive, only weakly positive. Other, methodologically strong, negative studies have not been considered, and several studies viewed as providing evidence supporting the carcinogenicity of silica have significant methodological weaknesses. Silica is not directly genotoxic and is a pulmonary carcinogen only in the rat, a species that seems to be inappropriate for assessing particulate carcinogenesis in humans. Data on humans demonstrate a lack of association between lung cancer and exposure to crystalline silica. Exposure-response relationships have generally not been found. Studies in which silicotic patients were not identified from compensation registries and in which enumeration was complete did not support a causal association between silicosis and lung cancer, which further argues against the carcinogenicity of crystalline silica.
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Affiliation(s)
- P A Hessel
- University of Alberta, Edmonton, Canada.
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Welch LS, Hunting KL, Balmes J, Bresnitz EA, Guidotti TL, Lockey JE, Myo-Lwin T. Variability in the classification of radiographs using the 1980 International Labor Organization Classification for Pneumoconioses. Chest 1998; 114:1740-8. [PMID: 9872210 DOI: 10.1378/chest.114.6.1740] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
This study describes the extent of agreement in classification of chest radiographs using the International Labor Organization (ILO) classification among six readers from the United States and Canada. A set of 119 radiographs was created and read by three Canadian and three US readers. The two ratings of interest were profusion (scored from 0/- to 3/+) and pleural abnormalities consistent with pneumoconiosis (scored with the ILO system, then collapsed into a yes/no). We used a number of approaches to evaluate interreader agreement on profusion and pleural changes, determining concordance, observed agreement, kappa statistic, and a new measure to approximate sensitivity and specificity. This study found that five of six readers had good fair to good agreement for pleural findings and for profusion as a dichotomous variable (> or = 1/0 vs < or = 0/1) using the kappa statistic, while a sixth reader had poor agreement. We found that concordance, expressed as percent agreement, was higher for normal radiographs than for ones that showed disease, and describe the use of the kappa statistic to control for this finding. This analysis adds to the existing literature with the use of the kappa statistic, and by presenting a new measure for "underreading" and "overreading" tendencies.
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Affiliation(s)
- L S Welch
- Department of Occupational/Environmental Medicine, Washington Hospital Center, Washington, DC 20010-2975, USA
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Takahashi K, Pan G, Kasai H, Hanaoka T, Feng Y, Liu N, Zhang S, Xu Z, Tsuda T, Yamato H, Higashi T, Okubo T. Relationship between Asbestos Exposures and 8-Hydroxydeoxyguanosine Levels in Leukocytic DNA of Workers at a Chinese Asbestos-material Plant. INTERNATIONAL JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HEALTH 1997; 3:111-119. [PMID: 9891108 DOI: 10.1179/107735297800407767] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
The objective of the study was to evaluate the level of 8-hydroxydeoxyguanosine (8-OHdG) in DNA of peripheral-blood leukocytes as a biological marker of asbestos exposure and/or its fibrotic effects in an occupational population exposed to asbestos. The setting was a large-scale asbestos plant in China producing brake linings, asbestos rubber, and textile using chrysotile. From a base population of active and retired workers with various levels of cumulative exposure to asbestos and grades of asbestosis, 39 study subjects were randomly selected to reflect incremental grades of asbestosis based on Chinese diagnostic standards. They consisted of 19 "normal" (control) and ten "suspected" and ten "definite" asbestosis-grade subjects, group-matched for age and sex. Leukocytic DNA was extracted from 5-mL samples of peripheral blood and 8-OHdG level measured by high-pressure liquid chromatography. A cumulative asbestos exposure index (CEI) was calculated for each subject as the summed product of duration and level of asbestos exposure per job, incorporating a job-exposure matrix. Geometric mean 8-OHdG levels showed a positive gradient in relation to increasing grades of asbestosis (control: 1.78, suspected: 2.21, definite: 2.58), with a significant difference between the control and definite-asbestosis subgroups (p < 0.05). The 8-OHdG level of the two subgroups combined as one "asbestosis" group was significantly higher than that of the control group (control: 1.78, asbestosis: 2.39, p = 0.01). Further, 8-OHdG levels were moderately correlated with CEIs for all subjects (r = 0.35, p < 0.05) and with grades of asbestosis for all (r = 0.47, p < 0.01) and for male subjects (r = 0.43, p < 0.05). In multiple regression analyses, grade of asbestosis explained 27% of the total variation in 8-OHdG and was a better predictor than CEI or duration of exposure. Thus, the 8-OHdG level in leukocytic DNA is related to grade of asbestosis and to individual cumulative exposure and may serve as a biologic marker reflecting the status of oxidative DNA damage by asbestos.
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Affiliation(s)
- K Takahashi
- Department of Environmental Epidemiology, University of Occupational and Environmental Health, Orio, Yahatanishiku, Kitakyushu City 807, Japan
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Abstract
OBJECTIVES To explore whether the inhalation of coal mine dust increases the risk of premature death in miners, a survival analysis was conducted in a cohort of 2738 patients with simple pneumoconiosis in the Huai-Bei coal mine, in China. METHODS Age specific mortalities were calculated by disease severity in terms of pneumoconiotic category with the life table method. The progressions from simple pneumoconiosis to death or progressive massive fibrosis (PMF) were analysed with the Cox's regression model with time as the dependent variable to identify risk factors. RESULTS During a follow up period (mean 8 y) 3.2% of patients with simple pneumoconiosis developed PMF. The patients with development of PMF presented higher age specific mortalities than those remaining in a state of simple pneumoconiosis (SMR: 3.42; P < 0.01). After adjustment for tuberculosis and duration of work, the relative risk of premature death due to development of PMF was 2.4. Tuberculosis was found to be a main risk factor which not only facilitated premature death (relative risk (RR): 2.0; P < 0.01), but was also a strong facilitator for development of PMF (RR: 7.0; P < 0.01). Also, a long term of work underground and drilling as a main job were identified as risk factors for development of PMF. CONCLUSION The results imply that patients with simple pneumoconiosis will have altered survival, and premature death among them is related to an increased risk of the development of PMF and the complication of tuberculosis.
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Affiliation(s)
- Q Yi
- Department of Pathobiology, Purdue University, West Lafayette, IN 47906, USA
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Chen RA, Hodous TK, Liang ZX, Petersen M, Den YC, Mclaughlin JK, Chen JQ, Blot WJ. A comparison of radiographic interpretation of silica exposed workers using the 1963 and the 1986 Chinese roentgenodiagnostic criteria of pneumoconioses. JOURNAL OF TONGJI MEDICAL UNIVERSITY = TONG JI YI KE DA XUE XUE BAO 1992; 12:120-3. [PMID: 1331488 DOI: 10.1007/bf02887794] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
As part of a larger study relating to silica exposure, silicosis, and lung cancer mortality in Chinese mine and factory workers, 1936 old posterior-anterior chest X-rays were re-interpreted according to the 1986 Chinese Roentgenodiagnostic Criteria of pneumoconioses. Each film was independently read by three individuals from a panel of eleven radiologists, and this reading was compared to the original one. Subsequent to the independent readings, a groups of three readers interpreted the films together, called the consensus readings. Comparisons were made by Chinese stage of pneumoconiosis. For the entire cohort, there was a crude agreement of 57.4% between the old and the new interpretations. Agreement within one step of full agreement was 92.5%. The interpretations done by median reading and by consensus were very similar. In general, there was a tendency for the old readings to be slightly higher compared to the new interpretations. This tendency was most marked in the tin mines, followed in decreasing order by the iron/copper mines, the potteries, and the tungsten mines. The agreement between the old and new interpretations is felt to be satisfactory.
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Affiliation(s)
- R A Chen
- Department of Labour Health and Occupational Diseases, Tongji Medical University, Wuhan
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