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Lauer DJ, Russell AJ, Lynch HN, Thompson WJ, Mundt KA, Checkoway H. Triangulation of epidemiological evidence and risk of bias evaluation: A proposed framework and applied example using formaldehyde exposure and risk of myeloid leukemias. GLOBAL EPIDEMIOLOGY 2024; 7:100143. [PMID: 38659700 PMCID: PMC11039339 DOI: 10.1016/j.gloepi.2024.100143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 04/01/2024] [Accepted: 04/05/2024] [Indexed: 04/26/2024] Open
Abstract
Evidence triangulation may help identify the impact of study design elements on study findings and to tease out biased results when evaluating potential causal relationships; however, methods for triangulating epidemiologic evidence are evolving and have not been standardized. Building upon key principles of epidemiologic evidence triangulation and risk of bias assessment, and responding to the National Academies of Sciences, Engineering, and Medicine (NASEM) call for applied triangulation examples, the objective of this manuscript is to propose a triangulation framework and to apply it as an illustrative example to epidemiologic studies examining the possible relationship between occupational formaldehyde exposure and risk of myeloid leukemias (ML) including acute (AML) and chronic (CML) types. A nine-component triangulation framework for epidemiological evidence was developed incorporating study quality and ROB guidance from various federal health agencies (i.e., US EPA TSCA and NTP OHAT). Several components of the triangulation framework also drew from widely used epidemiological analytic tools such as stratified meta-analysis and sensitivity analysis. Regarding the applied example, fourteen studies were identified and assessed using the following primary study quality domains to explore potential key sources of bias: 1) study design and analysis; 2) study participation; 3) exposure assessment; 4) outcome assessment; and 5) potential confounding. Across studies, methodological limitations possibly contributing to biased results were observed within most domains. Interestingly, results from one study - often providing the largest and least-precise relative risk estimates, likely reflecting study biases, deviated from most primary study findings indicating no such associations. Triangulation of epidemiological evidence appears to be helpful in exploring inconsistent results for the identification of study results possibly reflecting various biases. Nonetheless, triangulation methodologies require additional development and application to real-world examples to enhance objectivity and reproducibility.
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Affiliation(s)
| | | | | | | | - Kenneth A. Mundt
- Department of Biostatistics and Epidemiology, School of Public Health and Health Sciences, University of Massachusetts, Amherst, MA, United States of America
| | - Harvey Checkoway
- Herbert Wertheim School of Public Health, University of California, San Diego, United States of America
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Vincent MJ, Fitch S, Bylsma L, Thompson C, Rogers S, Britt J, Wikoff D. Assessment of associations between inhaled formaldehyde and lymphohematopoietic cancer through the integration of epidemiological and toxicological evidence with biological plausibility. Toxicol Sci 2024; 199:172-193. [PMID: 38547404 PMCID: PMC11131035 DOI: 10.1093/toxsci/kfae039] [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] [Indexed: 05/29/2024] Open
Abstract
Formaldehyde is recognized as carcinogenic for the portal of entry sites, though conclusions are mixed regarding lymphohematopoietic (LHP) cancers. This systematic review assesses the likelihood of a causal relationship between formaldehyde and LHP cancers by integrating components recommended by NASEM. Four experimental rodent bioassays and 16 observational studies in humans were included following the implementation of the a priori protocol. All studies were assessed for risk of bias (RoB), and meta-analyses were conducted on epidemiological studies, followed by a structured assessment of causation based on GRADE and Bradford Hill. RoB analysis identified systemic limitations precluding confidence in the epidemiological evidence due to inadequate characterization of formaldehyde exposure and a failure to adequately adjust for confounders or effect modifiers, thus suggesting that effect estimates are likely to be impacted by systemic bias. Mixed findings were reported in individual studies; meta-analyses did not identify significant associations between formaldehyde inhalation (when measured as ever/never exposure) and LHP outcomes, with meta-SMRs ranging from 0.50 to 1.51, depending on LHP subtype. No associations with LHP-related lesions were reported in reliable animal bioassays. No biologically plausible explanation linking the inhalation of FA and LHP was identified, supported primarily by the lack of systemic distribution and in vivo genotoxicity. In conclusion, the inconsistent associations reported in a subset of the evidence were not considered causal when integrated with the totality of the epidemiological evidence, toxicological data, and considerations of biological plausibility. The impact of systemic biases identified herein could be quantitatively assessed to better inform causality and use in risk assessment.
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Affiliation(s)
| | - Seneca Fitch
- ToxStrategies, LLC, Asheville, North Carolina 28801, United States
| | - Lauren Bylsma
- EpidStrategies, a Division of ToxStrategies, LLC, Katy, Texas 77494, United States
| | - Chad Thompson
- ToxStrategies, LLC, Katy, Texas 77494, United States
| | - Sarah Rogers
- ToxStrategies, LLC, Asheville, North Carolina 28801, United States
| | - Janice Britt
- ToxStrategies, LLC, Asheville, North Carolina 28801, United States
| | - Daniele Wikoff
- ToxStrategies, LLC, Asheville, North Carolina 28801, United States
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Locatelli F, Martinelli L, Marchetti P, Caliskan G, Badaloni C, Caranci N, de Hoogh K, Gatti L, Giorgi Rossi P, Guarda L, Ottone M, Panunzi S, Stafoggia M, Silocchi C, Ricci P, Marcon A. Residential exposure to air pollution and incidence of leukaemia in the industrial area of Viadana, Northern Italy. ENVIRONMENTAL RESEARCH 2024; 254:119120. [PMID: 38734295 DOI: 10.1016/j.envres.2024.119120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 04/29/2024] [Accepted: 05/09/2024] [Indexed: 05/13/2024]
Abstract
BACKGROUND Exposure to air pollution has been proposed as one of the potential risk factors for leukaemia. Work-related formaldehyde exposure is suspected to cause leukaemia. METHODS We conducted a nested register-based case-control study on leukaemia incidence in the Viadana district, an industrial area for particleboard production in Northern Italy. We recruited 115 cases and 496 controls, frequency-matched by age, between 1999 and 2014. We assigned estimated exposures to particulate matter (PM10, PM2.5), nitrogen dioxide (NO2), and formaldehyde at residential addresses, averaged over the susceptibility window 3rd to 10th year prior to the index date. We considered potential confounding by sex, age, nationality, socio-economic status, occupational exposures to benzene and formaldehyde, and prior cancer diagnoses. RESULTS There was no association of exposures to PM10, PM2.5, and NO2 with leukaemia incidence. However, an indication of increased risk emerged for formaldehyde, despite wide statistical uncertainty (OR 1.46, 95%CI 0.65-3.25 per IQR-difference of 1.2 μg/m3). Estimated associations for formaldehyde were higher for acute (OR 2.07, 95%CI 0.70-6.12) and myeloid subtypes (OR 1.79, 95%CI 0.64-5.01), and in the 4-km buffer around the industrial facilities (OR 2.78, 95%CI 0.48-16.13), although they remained uncertain. CONCLUSIONS This was the first study investigating the link between ambient formaldehyde exposure and leukaemia incidence in the general population. The evidence presented suggests an association, although it remains inconclusive, and a potential significance of emissions related to industrial activities in the district. Further research is warranted in larger populations incorporating data on other potential risk factors.
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Affiliation(s)
- Francesca Locatelli
- Unit of Epidemiology and Medical Statistics, Department of Diagnostics and Public Health, University of Verona, Verona, Italy
| | - Luigi Martinelli
- Unit of Epidemiology and Medical Statistics, Department of Diagnostics and Public Health, University of Verona, Verona, Italy
| | - Pierpaolo Marchetti
- Unit of Epidemiology and Medical Statistics, Department of Diagnostics and Public Health, University of Verona, Verona, Italy
| | - Gulser Caliskan
- Unit of Epidemiology and Medical Statistics, Department of Diagnostics and Public Health, University of Verona, Verona, Italy; Department of Medical Epidemiology and Biostatistics, Karolinska Institute, Solna, Sweden
| | - Chiara Badaloni
- Department of Epidemiology, Lazio Region Health Service ASL Roma 1, Rome, Italy
| | - Nicola Caranci
- Department of Innovation in Healthcare and Social Services, Emilia-Romagna Region, Bologna, Italy
| | - Kees de Hoogh
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland; University of Basel, Basel, Switzerland
| | - Luciana Gatti
- Struttura Complessa Osservatorio Epidemiologico, Agenzia di Tutela della Salute della Val Padana, Mantova, Italy
| | - Paolo Giorgi Rossi
- Servizio di Epidemiologia, Azienda USL-IRCCS di Reggio Emilia, Emilia-Romagna, Reggio Emilia, Italy
| | - Linda Guarda
- Struttura Complessa Osservatorio Epidemiologico, Agenzia di Tutela della Salute della Val Padana, Mantova, Italy
| | - Marta Ottone
- Servizio di Epidemiologia, Azienda USL-IRCCS di Reggio Emilia, Emilia-Romagna, Reggio Emilia, Italy
| | - Silvia Panunzi
- Unit of Epidemiology and Medical Statistics, Department of Diagnostics and Public Health, University of Verona, Verona, Italy
| | - Massimo Stafoggia
- Department of Epidemiology, Lazio Region Health Service ASL Roma 1, Rome, Italy
| | - Caterina Silocchi
- Struttura Semplice Salute e Ambiente, Agenzia di Tutela della Salute della Val Padana, Mantova, Italy
| | - Paolo Ricci
- Former Director UOC Osservatorio Epidemiologico, Agenzia di Tutela della Salute della Val Padana, Mantova, Italy
| | - Alessandro Marcon
- Unit of Epidemiology and Medical Statistics, Department of Diagnostics and Public Health, University of Verona, Verona, Italy.
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Cox LA, Thompson WJ, Mundt KA. Interventional probability of causation (IPoC) with epidemiological and partial mechanistic evidence: benzene vs. formaldehyde and acute myeloid leukemia (AML). Crit Rev Toxicol 2024; 54:252-289. [PMID: 38753561 DOI: 10.1080/10408444.2024.2337435] [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: 02/20/2024] [Accepted: 03/25/2024] [Indexed: 05/18/2024]
Abstract
INTRODUCTION Causal epidemiology for regulatory risk analysis seeks to evaluate how removing or reducing exposures would change disease occurrence rates. We define interventional probability of causation (IPoC) as the change in probability of a disease (or other harm) occurring over a lifetime or other specified time interval that would be caused by a specified change in exposure, as predicted by a fully specified causal model. We define the closely related concept of causal assigned share (CAS) as the predicted fraction of disease risk that would be removed or prevented by a specified reduction in exposure, holding other variables fixed. Traditional approaches used to evaluate the preventable risk implications of epidemiological associations, including population attributable fraction (PAF) and the Bradford Hill considerations, cannot reveal whether removing a risk factor would reduce disease incidence. We argue that modern formal causal models coupled with causal artificial intelligence (CAI) and realistically partial and imperfect knowledge of underlying disease mechanisms, show great promise for determining and quantifying IPoC and CAS for exposures and diseases of practical interest. METHODS We briefly review key CAI concepts and terms and then apply them to define IPoC and CAS. We present steps to quantify IPoC using a fully specified causal Bayesian network (BN) model. Useful bounds for quantitative IPoC and CAS calculations are derived for a two-stage clonal expansion (TSCE) model for carcinogenesis and illustrated by applying them to benzene and formaldehyde based on available epidemiological and partial mechanistic evidence. RESULTS Causal BN models for benzene and risk of acute myeloid leukemia (AML) incorporating mechanistic, toxicological and epidemiological findings show that prolonged high-intensity exposure to benzene can increase risk of AML (IPoC of up to 7e-5, CAS of up to 54%). By contrast, no causal pathway leading from formaldehyde exposure to increased risk of AML was identified, consistent with much previous mechanistic, toxicological and epidemiological evidence; therefore, the IPoC and CAS for formaldehyde-induced AML are likely to be zero. CONCLUSION We conclude that the IPoC approach can differentiate between likely and unlikely causal factors and can provide useful upper bounds for IPoC and CAS for some exposures and diseases of practical importance. For causal factors, IPoC can help to estimate the quantitative impacts on health risks of reducing exposures, even in situations where mechanistic evidence is realistically incomplete and individual-level exposure-response parameters are uncertain. This illustrates the strength that can be gained for causal inference by using causal models to generate testable hypotheses and then obtaining toxicological data to test the hypotheses implied by the models-and, where necessary, refine the models. This virtuous cycle provides additional insight into causal determinations that may not be available from weight-of-evidence considerations alone.
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Affiliation(s)
- Louis A Cox
- Cox Associates and University of Colorado, Denver, CO, USA
| | | | - Kenneth A Mundt
- Independent Consultants in Epidemiology, Amherst, MA, USA
- Adjunct Professor of Epidemiology, University of Massachusetts, Amherst, MA, USA
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Protano C, Buomprisco G, Cammalleri V, Pocino RN, Marotta D, Simonazzi S, Cardoni F, Petyx M, Iavicoli S, Vitali M. The Carcinogenic Effects of Formaldehyde Occupational Exposure: A Systematic Review. Cancers (Basel) 2021; 14:165. [PMID: 35008329 PMCID: PMC8749969 DOI: 10.3390/cancers14010165] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 12/28/2021] [Accepted: 12/28/2021] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Formaldehyde, classified as a carcinogen in 2004, as of today is widely used in many work activities. From its classification, further studies were performed to evaluate its carcinogenicity. The aim of the systematic review is to update the evidence on occupational exposure to formaldehyde and cancer onset. METHODS The review, in accordance with the PRISMA statement, includes articles in English reporting original results of studies conducted on workers exposed to formaldehyde, considering all types of cancer, published from 1 January 2000 to 30 July 2021 and selected from the Pubmed and Scopus databases. The studies' quality was assessed by the Newcastle-Ottawa Scale. RESULTS A total of 21 articles were included, conducted in different European, American, and Asian countries. The most investigated occupational areas are those characterized by a deliberate use of formaldehyde. Some studies evaluated all types of cancer, whereas others focused on specific sites such as thyroid and respiratory, lymphohematopoietic, or central nervous systems. The results showed weak associations with lung cancer, nasopharyngeal cancer, leukemia, and non-Hodgkin's lymphoma. CONCLUSIONS The results demonstrate the need for further original studies carried out on representative samples of workers exposed to measured levels of FA. These studies should be designed to reduce the bias due to co-exposure to other carcinogens.
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Affiliation(s)
- Carmela Protano
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy; (C.P.); (V.C.); (R.N.P.); (D.M.)
| | - Giuseppe Buomprisco
- Department of Human Anatomy, Histology, Forensic Medicine and Orthopedics, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy; (G.B.); (S.S.); (F.C.)
| | - Vittoria Cammalleri
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy; (C.P.); (V.C.); (R.N.P.); (D.M.)
| | - Roberta Noemi Pocino
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy; (C.P.); (V.C.); (R.N.P.); (D.M.)
| | - Daniela Marotta
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy; (C.P.); (V.C.); (R.N.P.); (D.M.)
| | - Stefano Simonazzi
- Department of Human Anatomy, Histology, Forensic Medicine and Orthopedics, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy; (G.B.); (S.S.); (F.C.)
| | - Francesca Cardoni
- Department of Human Anatomy, Histology, Forensic Medicine and Orthopedics, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy; (G.B.); (S.S.); (F.C.)
| | - Marta Petyx
- Department of Occupational and Environmental Medicine, Epidemiology and Hygiene, INAIL, Via Fontana Candida 1, 00078 Monte Porzio Catone, Rome, Italy; (M.P.); (S.I.)
| | - Sergio Iavicoli
- Department of Occupational and Environmental Medicine, Epidemiology and Hygiene, INAIL, Via Fontana Candida 1, 00078 Monte Porzio Catone, Rome, Italy; (M.P.); (S.I.)
| | - Matteo Vitali
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy; (C.P.); (V.C.); (R.N.P.); (D.M.)
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Pega F, Náfrádi B, Momen NC, Ujita Y, Streicher KN, Prüss-Üstün AM, Descatha A, Driscoll T, Fischer FM, Godderis L, Kiiver HM, Li J, Magnusson Hanson LL, Rugulies R, Sørensen K, Woodruff TJ. Global, regional, and national burdens of ischemic heart disease and stroke attributable to exposure to long working hours for 194 countries, 2000-2016: A systematic analysis from the WHO/ILO Joint Estimates of the Work-related Burden of Disease and Injury. ENVIRONMENT INTERNATIONAL 2021; 154:106595. [PMID: 34011457 PMCID: PMC8204267 DOI: 10.1016/j.envint.2021.106595] [Citation(s) in RCA: 123] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 04/16/2021] [Accepted: 04/20/2021] [Indexed: 05/21/2023]
Abstract
BACKGROUND World Health Organization (WHO) and International Labour Organization (ILO) systematic reviews reported sufficient evidence for higher risks of ischemic heart disease and stroke amongst people working long hours (≥55 hours/week), compared with people working standard hours (35-40 hours/week). This article presents WHO/ILO Joint Estimates of global, regional, and national exposure to long working hours, for 194 countries, and the attributable burdens of ischemic heart disease and stroke, for 183 countries, by sex and age, for 2000, 2010, and 2016. METHODS AND FINDINGS We calculated population-attributable fractions from estimates of the population exposed to long working hours and relative risks of exposure on the diseases from the systematic reviews. The exposed population was modelled using data from 2324 cross-sectional surveys and 1742 quarterly survey datasets. Attributable disease burdens were estimated by applying the population-attributable fractions to WHO's Global Health Estimates of total disease burdens. RESULTS In 2016, 488 million people (95% uncertainty range: 472-503 million), or 8.9% (8.6-9.1) of the global population, were exposed to working long hours (≥55 hours/week). An estimated 745,194 deaths (705,786-784,601) and 23.3 million disability-adjusted life years (22.2-24.4) from ischemic heart disease and stroke combined were attributable to this exposure. The population-attributable fractions for deaths were 3.7% (3.4-4.0) for ischemic heart disease and 6.9% for stroke (6.4-7.5); for disability-adjusted life years they were 5.3% (4.9-5.6) for ischemic heart disease and 9.3% (8.7-9.9) for stroke. CONCLUSIONS WHO and ILO estimate exposure to long working hours (≥55 hours/week) is common and causes large attributable burdens of ischemic heart disease and stroke. Protecting and promoting occupational and workers' safety and health requires interventions to reduce hazardous long working hours.
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Affiliation(s)
- Frank Pega
- Department of Environment, Climate Change and Health, World Health Organization, Geneva, Switzerland.
| | - Bálint Náfrádi
- Labour Administration, Labour Inspection and Occupational Safety and Health Branch, International Labour Organization, Geneva, Switzerland
| | - Natalie C Momen
- Department of Environment, Climate Change and Health, World Health Organization, Geneva, Switzerland
| | - Yuka Ujita
- Labour Administration, Labour Inspection and Occupational Safety and Health Branch, International Labour Organization, Geneva, Switzerland
| | - Kai N Streicher
- Department of Environment, Climate Change and Health, World Health Organization, Geneva, Switzerland
| | - Annette M Prüss-Üstün
- Department of Environment, Climate Change and Health, World Health Organization, Geneva, Switzerland
| | - Alexis Descatha
- UNIV Angers, CHU Angers, Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail) - UMR_S 1085, Angers, France; AP-HP (Paris Hospital), Occupational Health Unit, Poincaré University Hospital, Garches, France; Versailles St-Quentin Univ-Paris Saclay Univ (UVSQ), UMS 011, UMR-S 1168, France; Inserm, U1168 UMS 011, Villejuif, France
| | - Tim Driscoll
- Sydney School of Public Health, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Frida M Fischer
- Department of Environmental Health, School of Public Health, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Lode Godderis
- Department of Public Health and Primary Care, KU Leuven, Leuven, Belgium
| | | | - Jian Li
- Department of Environmental Health Sciences, Fielding School of Public Health, School of Nursing, University of California Los Angeles, Los Angeles, CA, USA
| | | | - Reiner Rugulies
- National Research Centre for the Working Environment, Copenhagen, Denmark; Department of Public Health, University of Copenhagen, Copenhagen, Denmark; Department of Psychology, University of Copenhagen, Copenhagen, Denmark
| | - Kathrine Sørensen
- National Research Centre for the Working Environment, Copenhagen, Denmark
| | - Tracey J Woodruff
- Program on Reproductive Health and the Environment, University of California San Francisco, San Francisco, CA, USA
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Rana I, Rieswijk L, Steinmaus C, Zhang L. Formaldehyde and Brain Disorders: A Meta-Analysis and Bioinformatics Approach. Neurotox Res 2021; 39:924-948. [PMID: 33400181 PMCID: PMC8102312 DOI: 10.1007/s12640-020-00320-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 11/30/2020] [Accepted: 12/01/2020] [Indexed: 02/07/2023]
Abstract
While there is significant investigation and investment in brain and neurodegenerative disease research, current understanding of the etiologies of illnesses like Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and brain cancer remains limited. Environmental exposure to the pollutant formaldehyde, an emerging neurotoxin widely used in industry, is suspected to play a critical role in mediating these disorders, although findings are limited and inconsistent. Focusing on highly exposed groups, we performed a meta-analysis of human epidemiological studies of formaldehyde and neurodegenerative disease (N = 19) or brain tumors (N = 12). To assess the biological plausibility of observed associations, we then conducted a bioinformatics analysis using WikiPathways and the Comparative Toxicogenomics Database and identified candidate genes and pathways that may be related to these interactions. We reported the meta-relative risk (meta-RR) of ALS following high exposures to formaldehyde was increased by 78% (meta-RR = 1.78, 95% confidence interval, CI 1.20-2.65). Similarly, the meta-RR for brain cancer was increased by 71% (meta-RR = 1.71; 95% CI 1.07-2.73) among highly exposed individuals. Multiple sensitivity analyses did not reveal sources of heterogeneity or bias. Our bioinformatics analysis revealed that the oxidative stress genes superoxide dismutase (SOD1, SOD2) and the pro-inflammatory marker tumor necrosis factor (TNF) were identified as the top relevant genes, and the folate metabolism, vitamin B12 metabolism, and the ALS pathways were highly affected by formaldehyde and related to the most brain diseases of interest. Further inquiry revealed the two metabolic pathways are also intimately tied with the formaldehyde cycle. Overall, our bioinformatics analysis supports the link of formaldehyde exposure to ALS or brain tumor reported from our meta-analysis. This new multifactorial approach enabled us to both interrogate the robustness of the epidemiological data and identify genes and pathways that may be involved in these interactions, ultimately lending strong evidence and potential biological plausibility for the association between formaldehyde exposure and brain disease.
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Affiliation(s)
- Iemaan Rana
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA, USA
| | - Linda Rieswijk
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA, USA
- Institute of Data Science, Maastricht University, Maastricht, Netherlands
| | - Craig Steinmaus
- Division of Epidemiology and Biostatistics, School of Public Health, University of California Berkeley, Berkeley, CA, USA
| | - Luoping Zhang
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA, USA.
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Chang ET, Ye W, Zeng YX, Adami HO. The Evolving Epidemiology of Nasopharyngeal Carcinoma. Cancer Epidemiol Biomarkers Prev 2021; 30:1035-1047. [PMID: 33849968 DOI: 10.1158/1055-9965.epi-20-1702] [Citation(s) in RCA: 102] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 01/15/2021] [Accepted: 03/26/2021] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND The epidemiology of nasopharyngeal carcinoma (NPC) has long been a source of fascination due to the malignancy's striking geographic distribution, the involvement of the oncogenic Epstein-Barr virus (EBV), the unique association with intake of Chinese-style salt-preserved fish, and etiologic heterogeneity by histologic subtype. METHODS This review summarizes the current epidemiologic literature on NPC, highlighting recent results from our population-based case-control study in southern China. RESULTS Findings from our case-control study provide new insight into the epidemiology of NPC, including a diminished role of Chinese-style salt-preserved fish, a profound impact of EBV genetic sequence variation, modest positive associations with passive smoking and household air pollution, and possible effects of oral health and the oral microbiome. Recent findings from other studies include a protective association with infectious mononucleosis, suggesting a causal role of early EBV infection; familial risk conferred by shared genetic variation in the host antibody-mediated immune response to EBV infection; and an unclear association with occupational exposure to formaldehyde. CONCLUSIONS To shed further light on the interplay of environmental, genetic, and viral causes of NPC, large pooled studies must accumulate sufficient cases with detailed exposure data. IMPACT New epidemiologic findings have reshaped the causal model for NPC.
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Affiliation(s)
- Ellen T Chang
- Center for Health Sciences, Exponent, Inc., Menlo Park, California.
- Department of Cancer Prevention Center, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
| | - Weimin Ye
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - Yi-Xin Zeng
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, and Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
- Beijing Hospital, Beijing, P.R. China
| | - Hans-Olov Adami
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
- Clinical Effectiveness Group, Institute of Health and Society, University of Oslo, Oslo, Norway
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Kang DS, Kim HS, Jung JH, Lee CM, Ahn YS, Seo YR. Formaldehyde exposure and leukemia risk: a comprehensive review and network-based toxicogenomic approach. Genes Environ 2021; 43:13. [PMID: 33845901 PMCID: PMC8042688 DOI: 10.1186/s41021-021-00183-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 03/19/2021] [Indexed: 12/20/2022] Open
Abstract
Formaldehyde is a widely used but highly reactive and toxic chemical. The International Agency for Research on Cancer classifies formaldehyde as a Group 1 carcinogen, based on nasopharyngeal cancer and leukemia studies. However, the correlation between formaldehyde exposure and leukemia incidence is a controversial issue. To understand the association between formaldehyde exposure and leukemia, we explored biological networks based on formaldehyde-related genes retrieved from public and commercial databases. Through the literature-based network approach, we summarized qualitative associations between formaldehyde exposure and leukemia. Our results indicate that oxidative stress-mediated genetic changes induced by formaldehyde could disturb the hematopoietic system, possibly leading to leukemia. Furthermore, we suggested major genes that are thought to be affected by formaldehyde exposure and associated with leukemia development. Our suggestions can be used to complement experimental data for understanding and identifying the leukemogenic mechanism of formaldehyde.
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Affiliation(s)
- Doo Seok Kang
- Department of Life Science, Institute of Environmental Medicine for Green Chemistry, Dongguk University Biomedi Campus, 32 Dongguk-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, 10326, Republic of Korea
| | - Hyun Soo Kim
- Department of Life Science, Institute of Environmental Medicine for Green Chemistry, Dongguk University Biomedi Campus, 32 Dongguk-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, 10326, Republic of Korea
| | - Jong-Hyeon Jung
- Faculty of Health Science, Daegu Haany University, Gyeongsan, Gyeongbuk, 38610, Republic of Korea
| | - Cheol Min Lee
- Department of Chemical and Biological Engineering, College of Natural Science and Engineering, Seokyeong University, Seoul, 02173, Republic of Korea
| | - Yeon-Soon Ahn
- Department of Preventive Medicine and Institute of Occupational and Environmental Medicine, Wonju College of Medicine, Yonsei University, Wonju, Gangwon, 26426, Republic of Korea
| | - Young Rok Seo
- Department of Life Science, Institute of Environmental Medicine for Green Chemistry, Dongguk University Biomedi Campus, 32 Dongguk-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, 10326, Republic of Korea.
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Mundt KA, Dell LD, Boffetta P, Beckett EM, Lynch HN, Desai VJ, Lin CK, Thompson WJ. The importance of evaluating specific myeloid malignancies in epidemiological studies of environmental carcinogens. BMC Cancer 2021; 21:227. [PMID: 33676443 PMCID: PMC7936449 DOI: 10.1186/s12885-021-07908-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 02/12/2021] [Indexed: 11/10/2022] Open
Abstract
INTRODUCTION Although myelodysplastic syndrome (MDS), acute myeloid leukemia (AML), myeloproliferative neoplasms (MPN) - including chronic myeloid leukemia (CML) - and myelodysplastic/myeloproliferative neoplasms (MDS/MPN) are largely clinically distinct myeloid malignancies, epidemiological studies rarely examine them separately and often combine them with lymphoid malignancies, limiting possible etiological interpretations for specific myeloid malignancies. METHODS We systematically evaluated the epidemiological literature on the four chemical agents (1,3-butadiene, formaldehyde, benzene, and tobacco smoking, excluding pharmaceutical, microbial and radioactive agents, and pesticides) classified by the International Agency for Research on Cancer as having sufficient epidemiological evidence to conclude that each causes "myeloid malignancies." Literature searches of IARC Monographs and PubMed identified 85 studies that we critically assessed, and for appropriate subsets, summarized results using meta-analysis. RESULTS Only two epidemiological studies on 1,3-butadiene were identified, but reported findings were inadequate to evaluate specific myeloid malignancies. Studies on formaldehyde reported results for AML and CML - and not for MDS or MPN - but reported no increased risks. For benzene, several specific myeloid malignancies were evaluated, with consistent associations reported with AML and MDS and mixed results for CML. Studies of tobacco smoking examined all major myeloid malignancies, demonstrating consistent relationships with AML, MDS and MPN, but not with CML. CONCLUSIONS Surprisingly few epidemiological studies present results for specific myeloid malignancies, and those identified were inconsistent across studies of the same exposure, as well as across chemical agents. This exercise illustrates that even for agents classified as having sufficient evidence of causing "myeloid malignancies," the epidemiological evidence for specific myeloid malignancies is generally limited and inconsistent. Future epidemiological studies should report findings for the specific myeloid malignancies, as combining them post hoc - where appropriate - always remains possible, whereas disaggregation may not. Furthermore, combining results across possibly discrete diseases reduces the chances of identifying important malignancy-specific causal associations.
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Affiliation(s)
| | - L D Dell
- Ramboll US Consulting Inc., Amherst, MA, USA
| | - P Boffetta
- Stony Brook Cancer Center, Stony Brook, NY, USA
- Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
| | | | | | - V J Desai
- Mount Sinai Hospital, New York, NY, USA
| | - C K Lin
- Cardno ChemRisk, Boston, MA, USA
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11
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Gentry R, Thompson CM, Franzen A, Salley J, Albertini R, Lu K, Greene T. Using mechanistic information to support evidence integration and synthesis: a case study with inhaled formaldehyde and leukemia. Crit Rev Toxicol 2021; 50:885-918. [PMID: 33538218 DOI: 10.1080/10408444.2020.1854678] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Formaldehyde is one of the most comprehensively studied chemicals, with over 30 years of research focused on understanding the development of cancer following inhalation. The causal conclusions regarding the potential for leukemia are largely based on the epidemiological literature, with little consideration of cancer bioassays, dosimetry studies, and mechanistic research, which challenge the biological plausibility of the disease. Recent reanalyzes of the epidemiological literature have also raised significant questions related to the purported associations between formaldehyde and leukemia. Because of this, considerable scientific debate and uncertainty remain on whether there is a causal association between formaldehyde inhalation exposure and leukemia. Further complexity in evaluating this association is related to the endogenous production of formaldehyde. Multiple modes of action (MOA) have been postulated for the development of leukemia following formaldehyde inhalation that includes unsupported hypotheses of direct or indirect toxicity to the target cell population. Herein, the available evidence relevant to evaluating the postulated MOAs for leukemia following formaldehyde inhalation exposure is organized in the IPCS MOA Framework. The integration of all the available evidence clearly highlights the limited amount of data that support any of the postulated MOAs and demonstrates a significant amount of research supporting the null hypothesis that there is no causal association between formaldehyde inhalation exposure and leukemia. These analyses result in a lack of confidence in any of the postulated MOAs, increasing confidence in the conclusion that there is a lack of biological plausibility for a causal association between formaldehyde inhalation exposure and leukemia.
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Affiliation(s)
| | | | | | | | - Richard Albertini
- Independent Consultant, Emeritus Professor, University of Vermont, Burlington, Vermont, USA
| | - Kun Lu
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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12
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Kwak K, Paek D, Park J. Occupational exposure to formaldehyde and risk of lung cancer: A systematic review and meta-analysis. Am J Ind Med 2020; 63:312-327. [PMID: 32003024 DOI: 10.1002/ajim.23093] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/15/2020] [Indexed: 01/08/2023]
Abstract
BACKGROUND Formaldehyde exposure is associated with nasopharyngeal cancer and leukemia. Previously-described links between formaldehyde exposure and lung cancer have been weak and inconsistent. We performed a systematic review and meta-analysis to evaluate quantitatively the association between formaldehyde exposure and lung cancer. METHODS We searched for articles on occupational formaldehyde exposure and lung cancer in PubMed, EMBASE, Web of Science, and CINAHL databases. In total, 32 articles were selected and 31 studies were included in a meta-analysis. Subgroup analyses and quality assessments were also performed. RESULTS The risk of lung cancer among workers exposed to formaldehyde was not significantly increased, with an overall pooled risk estimate of 1.04 (95% confidence interval [CI], 0.97-1.12). The pooled risk estimate of lung cancer was increased when higher exposure studies were considered (1.19; 95% CI, 0.96-1.46). More statistically robust results were obtained when high quality (1.13; 95% CI, 1.08-1.19) and recent (1.13; 95% CI, 1.07-1.19) studies were used in deriving pooled risk estimates. CONCLUSIONS No significant increase in the risk of lung cancer was evident in the overall pooled risk estimate; even in higher formaldehyde exposure groups. Our findings do not provide strong evidence in favor of formaldehyde as a risk factor for lung cancer. However, since risk estimates were significantly increased for high-quality and recent studies, the possibility that exposure to formaldehyde can increase the risk of lung cancer might still be considered.
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Affiliation(s)
- Kyeongmin Kwak
- Department of Occupational and Environmental MedicineKorea University Ansan HospitalAnsan Republic of Korea
- Department of Environmental SciencesSeoul National University Graduate School of Public HealthSeoul Republic of Korea
| | - Domyung Paek
- Department of Environmental SciencesSeoul National University Graduate School of Public HealthSeoul Republic of Korea
- Institute of Health and EnvironmentSeoul National UniversitySeoul Republic of Korea
| | - Jong‐Tae Park
- Department of Occupational and Environmental MedicineKorea University Ansan HospitalAnsan Republic of Korea
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13
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Catalani S, Donato F, Madeo E, Apostoli P, De Palma G, Pira E, Mundt KA, Boffetta P. Occupational exposure to formaldehyde and risk of non hodgkin lymphoma: a meta-analysis. BMC Cancer 2019; 19:1245. [PMID: 31870335 PMCID: PMC6929467 DOI: 10.1186/s12885-019-6445-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 12/09/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Formaldehyde, a widely used chemical, is considered a human carcinogen. We report the results of a meta-analyses of studies on the relationship between occupational exposure to formaldehyde and risk of non-Hodgkin lymphoma (NHL). METHODS We performed a systematic review and meta-analysis according to international guidelines and we identified 12 reports of occupational populations exposed to formaldehyde. We evaluated inter-study heterogeneity and we applied a random effects model. We conducted a cumulative meta-analysis and a meta-analysis according to estimated average exposure of each study population. RESULTS The meta-analysis resulted in a summary relative risk (RR) for NHL of 0.93 (95% confidence interval 0.83-1.04). The cumulative meta-analysis suggests that higher RRs were detected in studies published before 1986, while studies available after 1986 did not show an association. No differences were found between different levels of occupational exposure. Conclusions Notwithstanding some limitations, the results of this meta-analysis do not support the hypothesis of an association between occupational exposure to formaldehyde and risk of NHL.
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Affiliation(s)
- Simona Catalani
- Department of Medicine and Surgery Specialties, Radiological Sciences and Public Health University of Brescia, 25133, Brescia, Italy.
| | - Francesca Donato
- Department of Public Health and Pediatric Sciences, University of Turin, Turin, Italy
| | - Egidio Madeo
- Department of Medicine and Surgery Specialties, Radiological Sciences and Public Health University of Brescia, 25133, Brescia, Italy
| | - Pietro Apostoli
- Department of Medicine and Surgery Specialties, Radiological Sciences and Public Health University of Brescia, 25133, Brescia, Italy
| | - Giuseppe De Palma
- Department of Medicine and Surgery Specialties, Radiological Sciences and Public Health University of Brescia, 25133, Brescia, Italy
| | - Enrico Pira
- Department of Public Health and Pediatric Sciences, University of Turin, Turin, Italy
| | | | - Paolo Boffetta
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
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14
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Yu G, Zhang Y, Liu S, Fan L, Yang Y, Huang Y, Song J. Small interfering RNA targeting of peroxiredoxinⅡ gene enhances formaldehyde-induced toxicity in bone marrow cells isolated from BALB/c mice. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 181:89-95. [PMID: 31176251 DOI: 10.1016/j.ecoenv.2019.05.086] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 05/29/2019] [Accepted: 05/31/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUDS Formaldehyde (FA) is an important chemicals that can induce sick house syndrome and may be an incentive of childhood leukemia, however the exact mechanism is unclear. Oxidative stress may be an underlying reason of cancer occurring, while diverse antioxidants can protect the bone marrow cells (BMCs) from damaged. PeroxiredoxinⅡ (PrxⅡ) is an important member of the peroxiredoxin family, can remove reactive oxygen species (ROS), and is closely related with the occurrence of tumor. The present study aimed to detect a possible relationship between PrxⅡ gene and FA-induced bone marrow toxicity. METHODS The BMCs were taken out from BALB/c mice, then exposed to control and different doses of FA (50, 100, 200 μmol/L). The cell viability, ROS level and expressions of PrxⅡ gene were examined. Afterwards, we used a small interfering RNA (siRNA) to inhibit the expression of PrxⅡ gene, and chose 100 μmol/L FA for exposure dose, to examine the cell viability, ROS level, cell cycle, apoptotic rate, expressions of PrxⅡ gene in BMCs. RESULTS After a 24 h exposure to different doses of FA, the cell viability, expressions of PrxⅡ gene were decreased with the increasing of FA concentration, while the ROS level was increased. Inhibiting PrxⅡ gene's expression could enhance above FA-induced events. Additionally, siRNA targeting of PrxⅡcould aggravate cell cycle arrest to inhibit cell's growth and development, as well as increase apoptotic rates induced by FA. CONCLUSION These results demonstrated that PrxⅡ gene was involved in FA-induced bone marrow toxicity, and siRNA targeting of PrxⅡcould enhance this toxic process.
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Affiliation(s)
- Guangyan Yu
- (Department of Occupational and Environmental Health, School of Public Health, Jilin University, Changchun, Jilin Province130021, China.
| | - Yixin Zhang
- (Department of Occupational and Environmental Health, School of Public Health, Jilin University, Changchun, Jilin Province130021, China
| | - Shimeng Liu
- (Department of Occupational and Environmental Health, School of Public Health, Jilin University, Changchun, Jilin Province130021, China
| | - Lida Fan
- (Department of Occupational and Environmental Health, School of Public Health, Jilin University, Changchun, Jilin Province130021, China
| | - Yixue Yang
- (Department of Occupational and Environmental Health, School of Public Health, Jilin University, Changchun, Jilin Province130021, China
| | - Yulu Huang
- (Department of Occupational and Environmental Health, School of Public Health, Jilin University, Changchun, Jilin Province130021, China
| | - Jiayi Song
- (Department of Occupational and Environmental Health, School of Public Health, Jilin University, Changchun, Jilin Province130021, China
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15
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Checkoway H, Lees PSJ, Dell LD, Gentry PR, Mundt KA. Peak Exposures in Epidemiologic Studies and Cancer Risks: Considerations for Regulatory Risk Assessment. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2019; 39:1441-1464. [PMID: 30925210 PMCID: PMC6850123 DOI: 10.1111/risa.13294] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 12/22/2018] [Accepted: 12/24/2018] [Indexed: 05/20/2023]
Abstract
We review approaches for characterizing "peak" exposures in epidemiologic studies and methods for incorporating peak exposure metrics in dose-response assessments that contribute to risk assessment. The focus was on potential etiologic relations between environmental chemical exposures and cancer risks. We searched the epidemiologic literature on environmental chemicals classified as carcinogens in which cancer risks were described in relation to "peak" exposures. These articles were evaluated to identify some of the challenges associated with defining and describing cancer risks in relation to peak exposures. We found that definitions of peak exposure varied considerably across studies. Of nine chemical agents included in our review of peak exposure, six had epidemiologic data used by the U.S. Environmental Protection Agency (US EPA) in dose-response assessments to derive inhalation unit risk values. These were benzene, formaldehyde, styrene, trichloroethylene, acrylonitrile, and ethylene oxide. All derived unit risks relied on cumulative exposure for dose-response estimation and none, to our knowledge, considered peak exposure metrics. This is not surprising, given the historical linear no-threshold default model (generally based on cumulative exposure) used in regulatory risk assessments. With newly proposed US EPA rule language, fuller consideration of alternative exposure and dose-response metrics will be supported. "Peak" exposure has not been consistently defined and rarely has been evaluated in epidemiologic studies of cancer risks. We recommend developing uniform definitions of "peak" exposure to facilitate fuller evaluation of dose response for environmental chemicals and cancer risks, especially where mechanistic understanding indicates that the dose response is unlikely linear and that short-term high-intensity exposures increase risk.
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Affiliation(s)
- Harvey Checkoway
- Department of Family Medicine & Public HealthSan Diego School of Medicine, University of CaliforniaLa JollaCAUSA
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16
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Andersen ME, Gentry PR, Swenberg JA, Mundt KA, White KW, Thompson C, Bus J, Sherman JH, Greim H, Bolt H, Marsh GM, Checkoway H, Coggon D, Clewell HJ. Considerations for refining the risk assessment process for formaldehyde: Results from an interdisciplinary workshop. Regul Toxicol Pharmacol 2019; 106:210-223. [PMID: 31059732 DOI: 10.1016/j.yrtph.2019.04.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 04/17/2019] [Accepted: 04/21/2019] [Indexed: 01/06/2023]
Abstract
Anticipating the need to evaluate and integrate scientific evidence to inform new risk assessments or to update existing risk assessments, the Formaldehyde Panel of the American Chemistry Council (ACC), in collaboration with the University of North Carolina, convened a workshop: "Understanding Potential Human Health Cancer Risk - From Data Integration to Risk Evaluation" in October 2017. Twenty-four (24) invited-experts participated with expertise in epidemiology, toxicology, science integration and risk evaluation. Including members of the organizing committee, there were 29 participants. The meeting included eleven presentations encompassing an introduction and three sessions: (1) "integrating the formaldehyde science on nasal/nasopharyngeal carcinogenicity and potential for causality"; (2) "integrating the formaldehyde science on lymphohematopoietic cancer and potential for causality; and, (3) "formaldehyde research-data suitable for risk assessment". Here we describe key points from the presentations on epidemiology, toxicology and mechanistic studies that should inform decisions about the potential carcinogenicity of formaldehyde in humans and the discussions about approaches for structuring an integrated, comprehensive risk assessment for formaldehyde. We also note challenges expected when attempting to reconcile divergent results observed from research conducted within and across different scientific disciplines - especially toxicology and epidemiology - and in integrating diverse, multi-disciplinary mechanistic evidence.
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Affiliation(s)
- Melvin E Andersen
- ScitoVation LLC, 100 Capitola Drive, Drive 106, Durham, NC, 27713, USA.
| | | | - James A Swenberg
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA
| | - Kenneth A Mundt
- Ramboll US Corporation, Amherst, MA (currently with Cardno Chemrisk, Boston, MA, USA
| | | | | | - James Bus
- Center for Toxicology and Mechanistic Biology, Exponent, Alexandria, VA, USA
| | | | | | - Hermann Bolt
- Leibniz Institute for Working Environment and Human Factors (IfADo), Dortmund, Germany
| | - Gary M Marsh
- Department of Biostatistics, Center for Occupational Biostatistics and Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Harvey Checkoway
- University of California, San Diego, Department of Family Medicine and Public Health, USA
| | - David Coggon
- MRC Lifecourse Epidemiology Unit, University of Southampton, United Kingdom
| | - Harvey J Clewell
- Ramboll US Corporation, 6 Davis Drive, Suite 13, Research Triangle Park, NC, 27709, USA
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17
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Kwon SC, Kim I, Song J, Park J. Does formaldehyde have a causal association with nasopharyngeal cancer and leukaemia? Ann Occup Environ Med 2018; 30:5. [PMID: 29423228 PMCID: PMC5791191 DOI: 10.1186/s40557-018-0218-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 01/17/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The South Korean criteria for occupational diseases were amended in July 2013. These criteria included formaldehyde as a newly defined occupational carcinogen, based on cases of "leukemia or nasopharyngeal cancer caused by formaldehyde exposure". This inclusion was based on the Internal Agency for Research on Cancer classification, which classified formaldehyde as definite human carcinogen for nasopharyngeal cancer in 2004 and leukemia in 2012. METHODS We reviewed reports regarding the causal relationship between occupational exposure to formaldehyde in Korea and the development of these cancers, in order to determine whether these cases were work-related. RESULTS Previous reports regarding excess mortality from nasopharyngeal cancer caused by formaldehyde exposure seemed to be influenced by excess mortality from a single plant. The recent meta-risk for nasopharyngeal cancer was significantly increased in case-control studies, but was null for cohort studies (excluding unexplained clusters of nasopharyngeal cancers). A recent analysis of the largest industrial cohort revealed elevated risks of both leukemia and Hodgkin lymphoma at the peak formaldehyde exposure, and both cancers exhibited significant dose-response relationships. A nested case-control study of embalmers revealed that mortality from myeloid leukemia increased significantly with increasing numbers of embalms and with increasing formaldehyde exposure. The recent meta-risks for all leukemia and myeloid leukemia increased significantly. In South Korea, a few cases were considered occupational cancers as a result of mixed exposures to various chemicals (e.g., benzene), although no cases were compensated for formaldehyde exposure. The peak formaldehyde exposure levels in Korea were 2.70-14.8 ppm in a small number of specialized studies, which considered anatomy students, endoscopy employees who handled biopsy specimens, and manufacturing workers who were exposed to high temperatures. CONCLUSION Additional evidence is needed to confirm the relationship between formaldehyde exposure and nasopharyngeal cancer. All lymphohematopoietic malignancies, including leukemia, should be considered in cases with occupational formaldehyde exposure.
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Affiliation(s)
- Soon-Chan Kwon
- Department of Occupational and Environmental Medicine, College of Medicine Soonchunhyang University, Cheonan, Republic of Korea
| | - Inah Kim
- Department of Occupational and Environmental Medicine, College of Medicine, Hanyang University, 222 wangshimni-ro, Seoul, 04763 Republic of Korea
| | - Jaechul Song
- Department of Occupational and Environmental Medicine, College of Medicine, Hanyang University, 222 wangshimni-ro, Seoul, 04763 Republic of Korea
| | - Jungsun Park
- Department of Occupational Health, Catholic University of Daegu, Daegu, Republic of Korea
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Mundt KA, Gentry PR, Dell LD, Rodricks JV, Boffetta P. Six years after the NRC review of EPA's Draft IRIS Toxicological Review of Formaldehyde: Regulatory implications of new science in evaluating formaldehyde leukemogenicity. Regul Toxicol Pharmacol 2017; 92:472-490. [PMID: 29158043 DOI: 10.1016/j.yrtph.2017.11.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 10/27/2017] [Accepted: 11/15/2017] [Indexed: 11/28/2022]
Abstract
Shortly after the International Agency for Research on Cancer (IARC) determined that formaldehyde causes leukemia, the United States Environmental Protection Agency (EPA) released its Draft IRIS Toxicological Review of Formaldehyde ("Draft IRIS Assessment"), also concluding that formaldehyde causes leukemia. Peer review of the Draft IRIS Assessment by a National Academy of Science committee noted that "causal determinations are not supported by the narrative provided in the draft" (NRC 2011). They offered recommendations for improving the Draft IRIS assessment and identified several important research gaps. Over the six years since the NRC peer review, significant new science has been published. We identify and summarize key recommendations made by NRC and map them to this new science, including extended analysis of epidemiological studies, updates of earlier occupational cohort studies, toxicological experiments using a sensitive mouse strain, mechanistic studies examining the role of exogenous versus endogenous formaldehyde in bone marrow, and several critical reviews. With few exceptions, new findings are consistently negative, and integration of all available evidence challenges the earlier conclusions that formaldehyde causes leukemia. Given formaldehyde's commercial importance, environmental ubiquity and endogenous production, accurate hazard classification and risk evaluation of whether exposure to formaldehyde from occupational, residential and consumer products causes leukemia are critical.
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Affiliation(s)
- Kenneth A Mundt
- Environment and Health, Ramboll Environ, Amherst MA, United States.
| | - P Robinan Gentry
- Environment and Health, Ramboll Environ, Amherst MA, United States
| | - Linda D Dell
- Environment and Health, Ramboll Environ, Amherst MA, United States
| | | | - Paolo Boffetta
- Icahn School of Medicine at Mount Sinai, New York, NY, USA
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19
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Mundt KA, Gallagher AE, Dell LD, Natelson EA, Boffetta P, Gentry PR. Does occupational exposure to formaldehyde cause hematotoxicity and leukemia-specific chromosome changes in cultured myeloid progenitor cells? Crit Rev Toxicol 2017; 47:592-602. [PMID: 28462599 DOI: 10.1080/10408444.2017.1301878] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Several cross-sectional studies of a single population of workers exposed to formaldehyde at one of two factories using or producing formaldehyde-melamine resins in China have concluded that formaldehyde exposure induces damage to hematopoietic cells that originate in the bone marrow. Moreover, the investigators interpret observed differences between groups as evidence that formaldehyde induces myeloid leukemias, although the mechanisms for inducing these diseases are not obvious and recently published scientific findings do not support causation. Our objective was to evaluate hematological parameters and aneuploidy in relation to quantitative exposure measures of formaldehyde. We obtained the study data for the original study (Zhang et al. 2010 ) and performed linear regression analyses. Results showed that differences in white blood cell, granulocyte, platelet, and red blood cell counts are not exposure dependent. Among formaldehyde-exposed workers, no association was observed between individual average formaldehyde exposure estimates and frequency of aneuploidy, suggested by the original study authors to be indicators of myeloid leukemia risk.
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Affiliation(s)
| | | | | | - Ethan A Natelson
- b Houston Methodist Hospital - Texas Medical Center , Houston , TX , USA
| | - Paolo Boffetta
- c Icahn School of Medicine at Mount Sinai , New York , NY , USA
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20
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Nielsen GD, Larsen ST, Wolkoff P. Re-evaluation of the WHO (2010) formaldehyde indoor air quality guideline for cancer risk assessment. Arch Toxicol 2017; 91:35-61. [PMID: 27209488 PMCID: PMC5225186 DOI: 10.1007/s00204-016-1733-8] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Accepted: 04/27/2016] [Indexed: 11/11/2022]
Abstract
In 2010, the World Health Organization (WHO) established an indoor air quality guideline for short- and long-term exposures to formaldehyde (FA) of 0.1 mg/m3 (0.08 ppm) for all 30-min periods at lifelong exposure. This guideline was supported by studies from 2010 to 2013. Since 2013, new key studies have been published and key cancer cohorts have been updated, which we have evaluated and compared with the WHO guideline. FA is genotoxic, causing DNA adduct formation, and has a clastogenic effect; exposure-response relationships were nonlinear. Relevant genetic polymorphisms were not identified. Normal indoor air FA concentrations do not pass beyond the respiratory epithelium, and therefore FA's direct effects are limited to portal-of-entry effects. However, systemic effects have been observed in rats and mice, which may be due to secondary effects as airway inflammation and (sensory) irritation of eyes and the upper airways, which inter alia decreases respiratory ventilation. Both secondary effects are prevented at the guideline level. Nasopharyngeal cancer and leukaemia were observed inconsistently among studies; new updates of the US National Cancer Institute (NCI) cohort confirmed that the relative risk was not increased with mean FA exposures below 1 ppm and peak exposures below 4 ppm. Hodgkin's lymphoma, not observed in the other studies reviewed and not considered FA dependent, was increased in the NCI cohort at a mean concentration ≥0.6 mg/m3 and at peak exposures ≥2.5 mg/m3; both levels are above the WHO guideline. Overall, the credibility of the WHO guideline has not been challenged by new studies.
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Affiliation(s)
- Gunnar Damgård Nielsen
- National Research Centre for the Working Environment, Lersø Parkallé 105, 2100, Copenhagen, Denmark.
| | - Søren Thor Larsen
- National Research Centre for the Working Environment, Lersø Parkallé 105, 2100, Copenhagen, Denmark
| | - Peder Wolkoff
- National Research Centre for the Working Environment, Lersø Parkallé 105, 2100, Copenhagen, Denmark
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21
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Marsh GM, Morfeld P, Zimmerman SD, Liu Y, Balmert LC. An updated re-analysis of the mortality risk from nasopharyngeal cancer in the National Cancer Institute formaldehyde worker cohort study. J Occup Med Toxicol 2016; 11:8. [PMID: 26937249 PMCID: PMC4774098 DOI: 10.1186/s12995-016-0097-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 02/18/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND To determine whether the National Cancer Institute's (NCI) suggestion of a persistent increased mortality risk for nasopharyngeal cancer (NPC) in relation to formaldehyde (FA) exposure is robust with respect to alternative methods of data analysis. METHODS NCI provided the cohort data updated through 2004. We computed U.S. and local county rate-based standardized mortality ratios (SMRs) and internal cohort rate-based relative risks (RR) in relation to four formaldehyde exposure metrics (highest peak, average intensity, cumulative, and duration of exposure), using both NCI categories and alternative categorizations. We modeled the plant group-related interaction structure using continuous and categorical forms of each FA exposure metric and evaluated the impact of NCI's decision to exclude non-exposed workers from the baseline category. RESULTS Overall, our results corroborate the findings of our earlier reanalyses of data from the 1994 NCI cohort update. Six of 11 NPC deaths observed in the NCI study occurred in Plant 1, two (including the only additional NPC death) occurred in Plant 3 among workers in the lowest exposure category of highest peak, average intensity and cumulative FA exposure and in the second exposure category of duration of exposure, and the remaining cases occurred individually in three of eight remaining plants. A large, statistically significant, local rate-based NPC SMR of 7.34 (95 % CI = 2.69-15.97) among FA-exposed workers in Plant 1 contrasted with an 18 % deficit in NPC deaths (SMR = 0.82, 95 % CI = .17-2.41) among exposed workers in Plants 2-10. Overall, the new NCI findings led to: (1) reduced SMRs and RRs in the remaining nine study plants in unaffected exposure categories, (2) attenuated exposure-response relations for FA and NPC for all the FA metrics considered and (3) strengthened and expanded evidence that the earlier NCI internal analyses were non-robust and mis-specified as they did not account for a statistically significant interaction structure between plant group (Plant 1 vs. Plants 2-10) and FA exposure. CONCLUSIONS Our updated reanalysis provided little or no evidence to support NCI's suggestion of a persistent association between FA exposure and mortality from NPC. NCI's suggestion continues to be driven heavily by anomalous findings in one study plant (Plant 1).
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Affiliation(s)
- Gary M. Marsh
- />Center for Occupational Biostatistics and Epidemiology and Department of Biostatistics, Graduate School of Public Health, University of Pittsburgh, 130 DeSoto Street, Pittsburgh, PA 15261 USA
| | - Peter Morfeld
- />Institute and Policlinic for Occupational Medicine, Environmental Medicine and Preventive Research, University of Cologne, Cologne, Germany
- />Institute for Occupational Epidemiology and Risk Assessment of Evonik Industries, Essen, Germany
| | - Sarah D. Zimmerman
- />Center for Occupational Biostatistics and Epidemiology and Department of Biostatistics, Graduate School of Public Health, University of Pittsburgh, 130 DeSoto Street, Pittsburgh, PA 15261 USA
| | - Yimeng Liu
- />Center for Occupational Biostatistics and Epidemiology and Department of Biostatistics, Graduate School of Public Health, University of Pittsburgh, 130 DeSoto Street, Pittsburgh, PA 15261 USA
| | - Lauren C. Balmert
- />Center for Occupational Biostatistics and Epidemiology and Department of Biostatistics, Graduate School of Public Health, University of Pittsburgh, 130 DeSoto Street, Pittsburgh, PA 15261 USA
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Checkoway H, Dell LD, Boffetta P, Gallagher AE, Crawford L, Lees PSJ, Mundt KA. Formaldehyde Exposure and Mortality Risks From Acute Myeloid Leukemia and Other Lymphohematopoietic Malignancies in the US National Cancer Institute Cohort Study of Workers in Formaldehyde Industries. J Occup Environ Med 2015; 57:785-94. [PMID: 26147546 PMCID: PMC4479664 DOI: 10.1097/jom.0000000000000466] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OBJECTIVES To evaluate associations between cumulative and peak formaldehyde exposure and mortality from acute myeloid leukemia (AML) and other lymphohematopoietic malignancies. METHODS Cox proportional hazards analyses. RESULTS Acute myeloid leukemia was unrelated to cumulative exposure. Hodgkin lymphoma relative risk estimates in the highest exposure categories of cumulative and peak exposures were, respectively, 3.76 (Ptrend = 0.05) and 5.13 (Ptrend = 0.003). There were suggestive associations with peak exposure observed for chronic myeloid leukemia, albeit based on very small numbers. No other lymphohematopoietic malignancy was associated with either chronic or peak exposure. CONCLUSIONS Insofar as there is no prior epidemiologic evidence supporting associations between formaldehyde and either Hodgkin leukemia or chronic myeloid leukemia, any causal interpretations of the observed risk patterns are at most tentative. Findings from this re-analysis do not support the hypothesis that formaldehyde is a cause of AML.
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Affiliation(s)
- Harvey Checkoway
- From the Department of Family Medicine & Public Health (Dr Checkoway), University of California, San Diego School of Medicine, La Jolla; ENVIRON International Corporation (Mss Dell and Crawford, Drs Gallagher and Mundt), Amherst, Mass; Mount Sinai Hospital (Dr Boffetta), New York, NY; and Johns Hopkins Bloomberg School of Public Health (Dr Lees), Baltimore, Md
| | - Linda D. Dell
- From the Department of Family Medicine & Public Health (Dr Checkoway), University of California, San Diego School of Medicine, La Jolla; ENVIRON International Corporation (Mss Dell and Crawford, Drs Gallagher and Mundt), Amherst, Mass; Mount Sinai Hospital (Dr Boffetta), New York, NY; and Johns Hopkins Bloomberg School of Public Health (Dr Lees), Baltimore, Md
| | - Paolo Boffetta
- From the Department of Family Medicine & Public Health (Dr Checkoway), University of California, San Diego School of Medicine, La Jolla; ENVIRON International Corporation (Mss Dell and Crawford, Drs Gallagher and Mundt), Amherst, Mass; Mount Sinai Hospital (Dr Boffetta), New York, NY; and Johns Hopkins Bloomberg School of Public Health (Dr Lees), Baltimore, Md
| | - Alexa E. Gallagher
- From the Department of Family Medicine & Public Health (Dr Checkoway), University of California, San Diego School of Medicine, La Jolla; ENVIRON International Corporation (Mss Dell and Crawford, Drs Gallagher and Mundt), Amherst, Mass; Mount Sinai Hospital (Dr Boffetta), New York, NY; and Johns Hopkins Bloomberg School of Public Health (Dr Lees), Baltimore, Md
| | - Lori Crawford
- From the Department of Family Medicine & Public Health (Dr Checkoway), University of California, San Diego School of Medicine, La Jolla; ENVIRON International Corporation (Mss Dell and Crawford, Drs Gallagher and Mundt), Amherst, Mass; Mount Sinai Hospital (Dr Boffetta), New York, NY; and Johns Hopkins Bloomberg School of Public Health (Dr Lees), Baltimore, Md
| | - Peter SJ. Lees
- From the Department of Family Medicine & Public Health (Dr Checkoway), University of California, San Diego School of Medicine, La Jolla; ENVIRON International Corporation (Mss Dell and Crawford, Drs Gallagher and Mundt), Amherst, Mass; Mount Sinai Hospital (Dr Boffetta), New York, NY; and Johns Hopkins Bloomberg School of Public Health (Dr Lees), Baltimore, Md
| | - Kenneth A. Mundt
- From the Department of Family Medicine & Public Health (Dr Checkoway), University of California, San Diego School of Medicine, La Jolla; ENVIRON International Corporation (Mss Dell and Crawford, Drs Gallagher and Mundt), Amherst, Mass; Mount Sinai Hospital (Dr Boffetta), New York, NY; and Johns Hopkins Bloomberg School of Public Health (Dr Lees), Baltimore, Md
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Jones RM, Dell L, Torres C, Simmons CE, Poole J, Boelter FW, Harper P. Exposure Reconstruction and Risk Analysis for Six Semiconductor Workers With Lymphohematopoietic Cancers. J Occup Environ Med 2015; 57:649-58. [PMID: 25719533 PMCID: PMC4448668 DOI: 10.1097/jom.0000000000000413] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To investigate whether workplace exposures to recognized lymphohematopoietic carcinogens were possibly related to cancers in six semiconductor-manufacturing workers. METHODS A job-exposure matrix was developed for chemical and physical process agents and anticipated by-products. Potential cumulative occupational exposures of the six cases were reconstructed. The role of workplace exposures in cancer was evaluated through quantitative risk assessment and by comparison with epidemiological literature. RESULTS Two workers were potentially exposed to agents capable of causing their diagnosed cancers. Reconstructed exposures were similar to levels in outdoor environments and lower than exposures associated with increased risks in epidemiological studies. Cancer risks were estimated to be less than 1 in 10,000 persons. CONCLUSIONS The development of cancer among the six workers was unlikely to be explained by occupational exposures to recognized lymphohematopoietic carcinogens.
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Affiliation(s)
- Rachael M. Jones
- From ENVIRON International Corporation (Dr Jones, Ms Simmons, and Ms Boelter) and School of Public Health, University of Illinois at Chicago (Dr Jones); ENVIRON International Corporation (Ms Dell), Amherst, MA; ENVIRON International Corporation (Mr Torres), Atlanta, GA; ENVIRON International Corporation (Dr Poole), Tampa, FL; and ENVIRON International Corporation (Mr Harper), Phoenix, AZ. Ms Simmons is currently employed by Simmons Environmental and Occupational Health Solutions. Mr Torres is currently employed by Gates Rubber
| | - Linda Dell
- From ENVIRON International Corporation (Dr Jones, Ms Simmons, and Ms Boelter) and School of Public Health, University of Illinois at Chicago (Dr Jones); ENVIRON International Corporation (Ms Dell), Amherst, MA; ENVIRON International Corporation (Mr Torres), Atlanta, GA; ENVIRON International Corporation (Dr Poole), Tampa, FL; and ENVIRON International Corporation (Mr Harper), Phoenix, AZ. Ms Simmons is currently employed by Simmons Environmental and Occupational Health Solutions. Mr Torres is currently employed by Gates Rubber
| | - Craig Torres
- From ENVIRON International Corporation (Dr Jones, Ms Simmons, and Ms Boelter) and School of Public Health, University of Illinois at Chicago (Dr Jones); ENVIRON International Corporation (Ms Dell), Amherst, MA; ENVIRON International Corporation (Mr Torres), Atlanta, GA; ENVIRON International Corporation (Dr Poole), Tampa, FL; and ENVIRON International Corporation (Mr Harper), Phoenix, AZ. Ms Simmons is currently employed by Simmons Environmental and Occupational Health Solutions. Mr Torres is currently employed by Gates Rubber
| | - Catherine E. Simmons
- From ENVIRON International Corporation (Dr Jones, Ms Simmons, and Ms Boelter) and School of Public Health, University of Illinois at Chicago (Dr Jones); ENVIRON International Corporation (Ms Dell), Amherst, MA; ENVIRON International Corporation (Mr Torres), Atlanta, GA; ENVIRON International Corporation (Dr Poole), Tampa, FL; and ENVIRON International Corporation (Mr Harper), Phoenix, AZ. Ms Simmons is currently employed by Simmons Environmental and Occupational Health Solutions. Mr Torres is currently employed by Gates Rubber
| | - James Poole
- From ENVIRON International Corporation (Dr Jones, Ms Simmons, and Ms Boelter) and School of Public Health, University of Illinois at Chicago (Dr Jones); ENVIRON International Corporation (Ms Dell), Amherst, MA; ENVIRON International Corporation (Mr Torres), Atlanta, GA; ENVIRON International Corporation (Dr Poole), Tampa, FL; and ENVIRON International Corporation (Mr Harper), Phoenix, AZ. Ms Simmons is currently employed by Simmons Environmental and Occupational Health Solutions. Mr Torres is currently employed by Gates Rubber
| | - Fred W. Boelter
- From ENVIRON International Corporation (Dr Jones, Ms Simmons, and Ms Boelter) and School of Public Health, University of Illinois at Chicago (Dr Jones); ENVIRON International Corporation (Ms Dell), Amherst, MA; ENVIRON International Corporation (Mr Torres), Atlanta, GA; ENVIRON International Corporation (Dr Poole), Tampa, FL; and ENVIRON International Corporation (Mr Harper), Phoenix, AZ. Ms Simmons is currently employed by Simmons Environmental and Occupational Health Solutions. Mr Torres is currently employed by Gates Rubber
| | - Paul Harper
- From ENVIRON International Corporation (Dr Jones, Ms Simmons, and Ms Boelter) and School of Public Health, University of Illinois at Chicago (Dr Jones); ENVIRON International Corporation (Ms Dell), Amherst, MA; ENVIRON International Corporation (Mr Torres), Atlanta, GA; ENVIRON International Corporation (Dr Poole), Tampa, FL; and ENVIRON International Corporation (Mr Harper), Phoenix, AZ. Ms Simmons is currently employed by Simmons Environmental and Occupational Health Solutions. Mr Torres is currently employed by Gates Rubber
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Coggon D, Ntani G, Harris EC, Palmer KT. Upper airway cancer, myeloid leukemia, and other cancers in a cohort of British chemical workers exposed to formaldehyde. Am J Epidemiol 2014; 179:1301-11. [PMID: 24714728 PMCID: PMC4189094 DOI: 10.1093/aje/kwu049] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The International Agency for Research on Cancer controversially has classified formaldehyde as causing nasopharyngeal carcinoma and myeloid leukemia. To provide further information on this question, we extended follow-up of a cohort of 14,008 chemical workers at 6 factories in England and Wales, covering the period 1941-2012. Mortality was compared with national death rates for England and Wales, and associations with incident upper airway cancer and leukemia were explored in nested case-control analyses. We observed excess deaths from cancers of the esophagus (100 observed vs. 93.1 expected), stomach (182 vs. 141.4), rectum (107 vs. 86.8), liver (35 vs. 26.9), and lung (813 vs. 645.8), but none of these tumors exhibited a clear exposure-response relationship. Nested case-control analyses of 115 men with upper airway cancer (including 1 nasopharyngeal cancer), 92 men with leukemia, and 45 men with myeloid leukemia indicated no elevations of risk in the highest exposure category (high exposure for ≥1 year). When the 2 highest exposure categories were combined, the odds ratio for myeloid leukemia was 1.26 (95% confidence interval: 0.39, 4.08). Our results provide no support for an increased hazard of myeloid leukemia, nasopharyngeal carcinoma, or other upper airway tumors from formaldehyde exposure. These results indicate that any excess risk of these cancers, even from relatively high exposures, is at most small.
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Marsh GM, Morfeld P, Collins JJ, Symons JM. Issues of methods and interpretation in the National Cancer Institute formaldehyde cohort study. J Occup Med Toxicol 2014; 9:22. [PMID: 24855485 PMCID: PMC4030030 DOI: 10.1186/1745-6673-9-22] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 04/04/2014] [Indexed: 11/17/2022] Open
Abstract
In 2004, the International Agency for Research on Cancer (IARC) reclassified formaldehyde (FA) from a probable (Group 2A) to a known human carcinogen (Group 1) citing results for nasopharyngeal cancer (NPC) mortality from the follow-up through 1994 of the National Cancer Institute formaldehyde cohort study. To the contrary, in 2012, the Committee for Risk Assessment of the European Chemicals Agency disagreed with the proposal to classify FA as a known human carcinogen (Carc. 1A), proposing a lower but still protective category, namely as a substance which is presumed to have carcinogenic potential for humans (Carc. 1B). Thus, U.S. and European regulatory agencies currently disagree about the potential human carcinogenicity of FA. In 2013, the National Cancer Institute reported results from their follow-up through 2004 of the formaldehyde cohort and concluded that the results continue to suggest a link between FA exposure and NPC. We discuss in this commentary why we believe that this interpretation is neither consistent with the available data from the most recent update of the National Cancer Institute cohort study nor with other research findings from that cohort, other large cohort studies and the series of publications by some of the current authors, including an independent study of one of the National Cancer Institute's study plants. Another serious concern relates to the incorrectness of the data from the follow-up through 1994 of the National Cancer Institute study stemming from incomplete mortality ascertainment. While these data were corrected by the National Cancer Institute in subsequent supplemental publications, incorrect data from the original publications have been cited extensively in recent causal evaluations of FA, including IARC. We conclude that the NCI publications that contain incorrect data from the incomplete 1994 mortality follow-up should be retracted entirely or corrected via published errata in the corresponding journals, and efforts should be made to re-analyze data from the 2004 follow-up of the NCI cohort study.
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Affiliation(s)
- Gary M Marsh
- Center for Occupational Biostatistics and Epidemiology and Department of Biostatistics, Graduate School of Public Health, University of Pittsburgh, 130 DeSoto Street, Pittsburgh, PA 15261, USA
| | - Peter Morfeld
- Institute and Policlinic for Occupational Medicine, Environmental Medicine and Preventive Research, University of Cologne, Cologne, Germany
- Institute for Occupational Epidemiology and Risk Assessment of Evonik Industries, Essen, Germany
| | - James J Collins
- Epidemiology Department, 1803 Building, The Dow Chemical Company, Midland, MI, USA
| | - James Morel Symons
- Epidemiology Program, Integrated Health Services, E.I. du Pont de Nemours and Company, Newark, DE, USA
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McLaughlin JK, Tarone RE. Mortality from solid tumors in the updated NCI formaldehyde cohort. Am J Ind Med 2014; 57:486-7. [PMID: 24501017 DOI: 10.1002/ajim.22275] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2013] [Indexed: 11/09/2022]
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Pinkerton LE, Hein MJ, Meyers A, Kamel F. Assessment of ALS mortality in a cohort of formaldehyde-exposed garment workers. Amyotroph Lateral Scler Frontotemporal Degener 2013; 14:353-5. [PMID: 23570513 DOI: 10.3109/21678421.2013.778284] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Lynne E Pinkerton
- Industrywide Studies Branch, Division of Surveillance, Hazard Evaluations and Field Studies, National Institute for Occupational Safety and Health, 4676 Columbia Parkway, Cincinnati, OH 45226, USA.
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