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Shao J, Fu P, Wang S, Cheng H, Zhang X. Occupational exposure to silica and risk of gastrointestinal cancers: a systematic review and meta-analysis of cohort studies. Int Arch Occup Environ Health 2024; 97:231-251. [PMID: 38356028 DOI: 10.1007/s00420-024-02045-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 01/09/2024] [Indexed: 02/16/2024]
Abstract
BACKGROUND Although silica is a proven lung carcinogen, there is no convincing evidence linking crystalline silica to gastrointestinal malignancies. METHODS We detailedly searched studies on the link between gastrointestinal malignancies and occupational silica exposure. Studies published between 1987 and 2023 were found by searching PubMed, Scopus, Cochrane Library, and Web of Science databases. Further studies were included from reference searching. We conducted a meta-analysis of the incidence and mortality of gastrointestinal malignancies and occupational silica exposure. We computed pooled-risk estimates using random effects models. Egger's regression asymmetry test and a funnel plot were used to identify publication bias. Moreover, sensitivity analysis and subgroup analysis were out. RESULTS We identified 40 research with individuals from 13 different countries. The results indicate that occupational silica exposure raises the risk of gastric and esophageal cancer incidence, with pooled standardized incidence ratio of 1.35 (95% CI 1.21-1.51, p < 0.001), 1.31 (95% CI 1.04-1.65, p = 0.023), respectively, but there was a lack of statistically significant relationship between standardized mortality ratio. In addition, we found that silica exposure did not increase the risk of colorectal and pancreatic cancers. Occupational silica exposure was found to increase the risk of liver cancer, with pooled SIR and SMR of 1.19 (95% CI 1.04-1.35, p = 0.009), 1.24 (95% CI 1.03-1.49, p = 0.026), respectively. CONCLUSIONS We discovered a link between occupational silica exposure and gastrointestinal malignancies, with cancers of the liver, stomach, and esophagus being the most prevalent. Colorectal and pancreatic cancer were not linked to occupational silica exposure.
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Affiliation(s)
- Jiyuan Shao
- Institute of Environmental Science, Shanxi University, Taiyuan, China
| | - Pengfei Fu
- Department of Biology, Hong Kong Baptist University, Hong Kong, SAR, China
- Golden Meditech Centre for NeuroRegeneration Sciences, Hong Kong Baptist University, Hong Kong, SAR, China
| | - Shengchun Wang
- Institute of Environmental Science, Shanxi University, Taiyuan, China
| | - Hong Cheng
- Institute of Environmental Science, Shanxi University, Taiyuan, China
| | - Xin Zhang
- Institute of Environmental Science, Shanxi University, Taiyuan, China.
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Ndlovu N, Richards G, Vorajee N, Murray J. Silicosis and pulmonary tuberculosis in deceased female South African miners. Occup Med (Lond) 2020; 69:272-278. [PMID: 31121039 DOI: 10.1093/occmed/kqz067] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Implementation of South Africa's 2002 Mining Charter increased women's participation in underground mining. However, occupational lung diseases (OLDs) in female gold miners have not been studied. AIMS To compare autopsy-diagnosed pulmonary silicosis, lymph gland silicosis (a precursor of pulmonary silicosis) and active pulmonary tuberculosis (PTB) in South African gold miners. METHODS The law allows for autopsies on miners for OLD compensation. Information is stored on the Pathology Automation (PATHAUT) database. We selected records of deceased miners who had worked only in gold mines, started employment from 2002, and were autopsied between 2005 and 2015. Using descriptive statistics, we compared demographic and employment characteristics, and disease proportions by sex. RESULTS The study comprised 847 gold miners: 68 women and 779 men. There were no statistically significant differences in proportions of autopsy-diagnosed pulmonary silicosis [3 (4%) in women and 54 (7%) in men], lymph gland silicosis [11 (16%) and 171 (22%)] or PTB [29 (43%) and 254 (33%)]. Age and employment duration in women and men with disease were similar. Most miners with pulmonary silicosis had started employment from 2003 [315 (77%)] and worked for under 10 years. CONCLUSION It is important to report research findings by sex. Proportions of silicosis and PTB were comparable in women and men, suggesting similar exposures. Silicosis detection after short employment indicates inadequate dust control, particularly as most entered the industry after implementation of interventions to control silica dust in 2003.
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Affiliation(s)
- N Ndlovu
- School of Public Health, University of the Witwatersrand, Johannesburg, South Africa
| | - G Richards
- Division of Critical Care, Charlotte Maxeke Hospital and Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - N Vorajee
- National Institute for Occupational Health, National Health Laboratory Service, Johannesburg, South Africa.,School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - J Murray
- School of Public Health, University of the Witwatersrand, Johannesburg, South Africa.,National Institute for Occupational Health, National Health Laboratory Service, Johannesburg, South Africa
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Laohasiriwong W, Srathonghon W, Phajan T, Assana S, Intamat S. Dust exposure and lung function of workers in the brick and clay pottery factories in the Northeast of Thailand. ACTA ACUST UNITED AC 2017. [DOI: 10.1080/00207233.2017.1341738] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Wongsa Laohasiriwong
- Department of Public Health Administration, Faculty of Public Health and Research and Training Centre for Enhancing Quality of Life for Working Age People, Khon Kaen University, Khon Kaen, Thailand
| | | | - Teerasak Phajan
- Community Public Health, Sirindhorn College Public Health, Khon Kaen, Thailand
| | - Supat Assana
- Community Public Health, Sirindhorn College Public Health, Khon Kaen, Thailand
| | - Somsak Intamat
- That Phanom Crown Prince Hospital, Nakorn Phanom, Thailand
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Möhner M, Pohrt A, Gellissen J. Occupational exposure to respirable crystalline silica and chronic non-malignant renal disease: systematic review and meta-analysis. Int Arch Occup Environ Health 2017; 90:555-574. [PMID: 28409224 PMCID: PMC5583269 DOI: 10.1007/s00420-017-1219-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 04/05/2017] [Indexed: 12/12/2022]
Abstract
Background While occupational exposure to respirable silica is known to lead to lung disease, most notably silicosis, its association with chronic kidney disease is unclear. Objectives This review explores the association between occupational exposure to respirable silica and chronic non-malignant renal disease such as glomerulonephritis. The evidence has been collected and compiled. Possible sources of bias are thoroughly discussed. Methods Cohort studies with silica exposure and case–control studies of renal disease were searched in PubMed until January 2015. Two authors independently abstracted data; any disagreement was resolved by consulting a third reviewer. A meta-analysis was performed to evaluate the association to silica exposure. Results A total of 23 cohort and four case–control studies were included in the analysis. The meta-analysis of cohort studies yielded elevated overall SMRs for renal disease. Some studies, however, included dose–response analyses, most of which did not show a positive trend. The approaches and results of the case–control studies were very heterogeneous. Conclusions While the studies of cohorts exposed to silica found elevated SMRs for renal disease, no clear evidence of a dose–response relationship emerged. The elevated risk may be attributed to diagnostic and methodological issues. In order to permit a reliable estimation of a possible causal link, exposed cohorts should be monitored for renal disease, as the information from mortality studies is hardly reliable in this field. Electronic supplementary material The online version of this article (doi:10.1007/s00420-017-1219-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Matthias Möhner
- Division of Work and Health, Federal Institute for Occupational Safety and Health, Nöldnerstr. 40/42, 10317, Berlin, Germany.
| | - Anne Pohrt
- Division of Work and Health, Federal Institute for Occupational Safety and Health, Nöldnerstr. 40/42, 10317, Berlin, Germany
| | - Johannes Gellissen
- Division of Work and Health, Federal Institute for Occupational Safety and Health, Nöldnerstr. 40/42, 10317, Berlin, Germany
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Poinen-Rughooputh S, Rughooputh MS, Guo Y, Rong Y, Chen W. Occupational exposure to silica dust and risk of lung cancer: an updated meta-analysis of epidemiological studies. BMC Public Health 2016; 16:1137. [PMID: 27814719 PMCID: PMC5095988 DOI: 10.1186/s12889-016-3791-5] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 10/21/2016] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Crystalline silica is considered as one of the most common and serious occupational hazards to workers' health. Although its association with lung cancer has been studied for many decades, the conclusion remains somewhat controversial. Our objectives are to review and summarize the epidemiological evidence on the relationship between occupational silica exposure and risk of lung cancer and to provide an update on this major occupational health concern. METHODS Eligible studies up to 29 April 2016 were identified. Pooled effect estimates were calculated according to the reported outcome and the study design. Cohort, case control and proportional mortality studies were examined separately. Studies reporting results according to silicotic status were grouped together and analyzed. Due to the significant amount of heterogeneity expected, random effects models were implemented. Subgroup and meta-regression analyses (both univariate and multivariate) were performed in an attempt to explain heterogeneity. Studies which had adequate exposure characterization were selected to find out whether there was an exposure-response relationship between silica and lung cancer. RESULTS The risk of lung cancer was found to be elevated in both silicotics and non-silicotics. The pooled standardized mortality ratio (SMR) was 2.32 with a 95 % confidence interval (95 % CI) of 1.91-2.81 and 1.78 (95 % CI 1.07-2.96) respectively. The pooled standardized incidence ratio (SIR) was 2.49 (95 % CI 1.87-3.33) and 1.18 (95 % CI 0.86-1.62) respectively. Subgroup analysis showed that workers in the mining industry had the highest risk of lung cancer with a pooled SMR of 1.48 (95 % CI 1.18-1.86) and the weakest association was seen in potteries with a pooled SMR of 1.14 (95 % CI 1.05-1.23). A positive exposure-response relation was found between cumulative silica exposure and risk of lung cancer. CONCLUSION The results of our meta-analysis supported the carcinogenic role of silica on the lungs, which was more pronounced at higher levels of exposure, in the presence of silicosis and in the mining industry. Further research is needed to evaluate whether non-silicotics are truly at risk, whether a predisposing factor would explain this potential risk, and to determine the mechanism of carcinogenicity of silica in humans.
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Affiliation(s)
- Satiavani Poinen-Rughooputh
- Department of Occupational & Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030 China
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030 China
| | - Mahesh Shumsher Rughooputh
- Department of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030 China
| | - Yanjun Guo
- Department of Occupational & Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030 China
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030 China
| | - Yi Rong
- Department of Occupational & Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030 China
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030 China
| | - Weihong Chen
- Department of Occupational & Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030 China
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030 China
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An approach to adjust standardized mortality ratios for competing cause of death in cohort studies. Int Arch Occup Environ Health 2015; 89:593-8. [PMID: 26483290 PMCID: PMC4828478 DOI: 10.1007/s00420-015-1097-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 10/02/2015] [Indexed: 11/11/2022]
Abstract
Purpose The calculation of standardized mortality ratios (SMRs) is a standard tool for the estimation of health risks in occupational epidemiology. An increasing number of studies deal with the analysis of the mortality in employees suffering from an occupational disease like silicosis or coal-worker pneumoconiosis (CWP). Their focus lies not on the mortality risk due to the occupational disease itself, but on other diseases such as lung cancer or heart diseases. Using population-based reference rates in these studies can cause misleading results because mortality rates of the general population do not reflect the elevated mortality due to the occupational disease investigated. Hence, the purpose of the present paper is to develop an approach to adjust the risk estimates for other causes of death with respect to the effect of an occupational disease as a competing cause of death in occupational mortality cohort studies. Methods To overcome the problems associated with SMRs, the paper makes use of proportional mortality ratios (PMR), which are a further approach for the estimation of health risks in occupational epidemiology. The cause-specific SMR can be rewritten as a product of PMR times the overall SMR. The PMR can be adjusted by ignoring the competing cause of death. Hence, an adjusted cause-specific SMR can be derived by multiplying this adjusted PMR with the overall SMR. This approach is applied to studies concerning lung cancer risk in coal miners suffering from CWP. Results and conclusions The usual approach for calculating SMRs leads to an underestimation of the real lung cancer risk in subgroups of miners suffering from CWP. The same effect can be observed in workers exposed to respirable silica already suffering from silicosis. The presented approach results in more realistic risk estimation in mortality cohort studies of employees suffering from an occupational disease. It is easily calculable on the basis of usually published values of observed cases and the corresponding cause-specific SMR.
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Mossman BT, Glenn RE. Bioreactivity of the crystalline silica polymorphs, quartz and cristobalite, and implications for occupational exposure limits (OELs). Crit Rev Toxicol 2013; 43:632-60. [PMID: 23863112 DOI: 10.3109/10408444.2013.818617] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Silica or silicon dioxides (SiO₂) are naturally occurring substances that comprise the vast majority of the earth's crust. Because of their prevalence and commercial applications, they have been widely studied for their potential to induce pulmonary fibrosis and other disorders. Historically, the focus in the workplace has been on the development of inflammation and fibrotic lung disease, the basis for promulgating workplace standards to protect workers. Crystalline silica (CS) polymorphs, predominantly quartz and cristobalite, are used in industry but are different in their mineralogy, chemistry, surface features, size dimensions and association with other elements naturally and during industrial applications. Epidemiologic, clinical and experimental studies in the literature historically have predominantly focused on quartz polymorphs. Thus, in this review, we summarize past scientific evaluations and recent peer-reviewed literature with an emphasis on cristobalite, in an attempt to determine whether quartz and cristobalite polymorphs differ in their health effects, toxicity and other properties that may dictate the need for various standards of protection in the workplace. In addition to current epidemiological and clinical reports, we review in vivo studies in rodents as well as cell culture studies that shed light on mechanisms intrinsic to the toxicity, altered cell responses and protective or defense mechanisms in response to these minerals. The medical and scientific literature indicates that the mechanisms of injury and potential causation of inflammation and fibrotic lung disease are similar for quartz and cristobalite. Our analysis of these data suggests similar occupational exposure limits (OELs) for these minerals in the workplace.
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Affiliation(s)
- Brooke T Mossman
- Department of Pathology, University of Vermont College of Medicine, Burlington, VT 05405-0068, USA.
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Chen M, Tse LA. Laryngeal cancer and silica dust exposure: a systematic review and meta-analysis. Am J Ind Med 2012; 55:669-76. [PMID: 22457229 DOI: 10.1002/ajim.22037] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/26/2012] [Indexed: 01/16/2023]
Abstract
BACKGROUND Individual epidemiological studies generally lack the power to examine the association between silica exposure or silicosis and laryngeal cancer. We summarized pertinent evidence from published literature by using meta-analysis. METHODS A systematic literature search was performed to identify cohort and case-control studies, and the method of meta-analysis was used to combine standardized mortality ratios (SMRs) or standardized incidence ratios (SIRs) from cohort studies and odds ratios (ORs) from case-control studies. RESULTS A significantly increased risk of laryngeal cancer (pooled OR = 1.39, 95% confidence interval (95% CI): 1.17-1.67) among workers exposed to silica dust was observed by combining six case-control studies with adjustment for smoking and alcohol consumption. A similarly increased but statistically non-significant risk estimate was observed from cohort studies, with a pooled SMR of 1.38 (95% CI: 0.79-1.96) for silicosis cases; and a pooled SMR of 1.13 (95% CI: 0.82-1.45) and a pooled SIR of 1.50 (95% CI: 0.59-2.42) for workers with silica dust exposure. CONCLUSION This systematic review demonstrated a weak association between silica or silicosis and laryngeal cancer. Owing to the inherent limitations of the original studies, interpretation of the results of this meta-analysis should be cautious.
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Affiliation(s)
- Minghui Chen
- The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, HKSAR, China
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Lung cancer and interstitial lung diseases: a systematic review. Pulm Med 2012; 2012:315918. [PMID: 22900168 PMCID: PMC3414065 DOI: 10.1155/2012/315918] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Revised: 05/29/2012] [Accepted: 06/01/2012] [Indexed: 12/21/2022] Open
Abstract
Interstitial lung diseases (ILDs) represent a heterogeneous group of more than two hundred diseases of either known or unknown etiology with different pathogenesis and prognosis. Lung cancer, which is the major cause of cancer death in the developed countries, is mainly attributed to cigarette smoking and exposure to inhaled carcinogens. Different studies suggest a link between ILDs and lung cancer, through different pathogenetic mechanisms, such as inflammation, coagulation, dysregulated apoptosis, focal hypoxia, activation, and accumulation of myofibroblasts as well as extracellular matrix accumulation. This paper reviews current evidence on the association between lung cancer and interstitial lung diseases such as idiopathic pulmonary fibrosis, sarcoidosis, systemic sclerosis, dermatomyositis/polymyositis, rheumatoid arthritis, systemic lupus erythematosus, and pneumoconiosis.
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Scarselli A, Binazzi A, Forastiere F, Cavariani F, Marinaccio A. Industry and job-specific mortality after occupational exposure to silica dust. Occup Med (Lond) 2011; 61:422-9. [DOI: 10.1093/occmed/kqr060] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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Is exposure to silica associated with lung cancer in the absence of silicosis? A meta-analytical approach to an important public health question. Int Arch Occup Environ Health 2008; 82:997-1004. [DOI: 10.1007/s00420-008-0387-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Accepted: 11/05/2008] [Indexed: 01/24/2023]
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Scarselli A, Binazzi A, Marinaccio A. Occupational exposure to crystalline silica: estimating the number of workers potentially at high risk in Italy. Am J Ind Med 2008; 51:941-9. [PMID: 18651580 DOI: 10.1002/ajim.20619] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Occupational exposure to free silica is widespread in several economic sectors and is well known to cause silicosis. This study was designed to establish a database of enterprises and workers in industrial sectors involving silica exposure in Italy and to estimate the number of workers potentially at high risk of exposure. METHODS The industrial sectors at risk of silica exposure were identified by selecting the industrial sector that employed people who were compensated for silicosis in 2000-2004. The enterprises and the number of workers (blue-collar) potentially at risk of silica exposure were selected from the Italian database of workplaces. RESULTS The number of workers potentially at high risk of silica exposure, were 28,712. The most involved sectors were: construction, mining and quarrying, metal working, and manufacturing of non-metallic products. Among regions in Italy, some exposure-disease scenarios were cited in literature, particularly in Sardinia, Liguria, and Tuscany. CONCLUSIONS Establishing a database of industries related to silica dust exposure and identifying the number of workers potentially at high risk can be useful to reinforce preventive measures and to control exposure.
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Affiliation(s)
- Alberto Scarselli
- National Institute for Occupational Safety and Prevention (ISPESL), Occupational Medicine Department, Epidemiology Unit, Rome, Italy.
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