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Borgert CJ. Hypothesis-driven weight of evidence evaluation indicates styrene lacks endocrine disruption potential. Crit Rev Toxicol 2023:1-16. [PMID: 37216681 DOI: 10.1080/10408444.2022.2112652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 08/01/2022] [Accepted: 08/02/2022] [Indexed: 05/24/2023]
Abstract
Styrene is among the U.S. EPA's List 2 chemicals for Tier 1 endocrine screening subject to the agency's two-tiered Endocrine Disruptor Screening Program (EDSP). Both U.S. EPA and OECD guidelines require a Weight of Evidence (WoE) to evaluate a chemical's potential for disrupting the endocrine system. Styrene was evaluated for its potential to disrupt estrogen, androgen, thyroid, and steroidogenic (EATS) pathways using a rigorous WoE methodology that included problem formulation, systematic literature search and selection, data quality evaluation, relevance weighting of endpoint data, and application of specific interpretive criteria. Sufficient data were available to assess the endocrine disruptive potential of styrene based on endpoints that would respond to EATS modes of action in some Tier 1-type and many Tier 2-type reproductive, developmental, and repeat dose toxicity studies. Responses to styrene were inconsistent with patterns of responses expected for chemicals and hormones known to operate via EATS MoAs, and thus, styrene cannot be deemed an endocrine disruptor, a potential endocrine disruptor, or to exhibit endocrine disruptive properties. Because Tier 1 EDSP screening results would trigger Tier 2 studies, like those evaluated here, subjecting styrene to further endocrine screening would produce no additional useful information and would be unjustified from animal welfare perspectives.
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Affiliation(s)
- Christopher J Borgert
- Applied Pharmacology and Toxicology Inc, Gainesville, FL, USA
- Department of Physiological Sciences, University of Florida College of Veterinary Medicine, Gainesville, FL, USA
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Banton MI, Bus JS, Collins JJ, Delzell E, Gelbke HP, Kester JE, Moore MM, Waites R, Sarang SS. Evaluation of potential health effects associated with occupational and environmental exposure to styrene - an update. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2019; 22:1-130. [PMID: 31284836 DOI: 10.1080/10937404.2019.1633718] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The potential chronic health risks of occupational and environmental exposure to styrene were evaluated to update health hazard and exposure information developed since the Harvard Center for Risk Analysis risk assessment for styrene was performed in 2002. The updated hazard assessment of styrene's health effects indicates human cancers and ototoxicity remain potential concerns. However, mechanistic research on mouse lung tumors demonstrates these tumors are mouse-specific and of low relevance to human cancer risk. The updated toxicity database supports toxicity reference levels of 20 ppm (equates to 400 mg urinary metabolites mandelic acid + phenylglyoxylic acid/g creatinine) for worker inhalation exposure and 3.7 ppm and 2.5 mg/kg bw/day, respectively, for general population inhalation and oral exposure. No cancer risk value estimates are proposed given the established lack of relevance of mouse lung tumors and inconsistent epidemiology evidence. The updated exposure assessment supports inhalation and ingestion routes as important. The updated risk assessment found estimated risks within acceptable ranges for all age groups of the general population and workers with occupational exposures in non-fiber-reinforced polymer composites industries and fiber-reinforced polymer composites (FRP) workers using closed-mold operations or open-mold operations with respiratory protection. Only FRP workers using open-mold operations not using respiratory protection have risk exceedances for styrene and should be considered for risk management measures. In addition, given the reported interaction of styrene exposure with noise, noise reduction to sustain levels below 85 dB(A) needs be in place.
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Affiliation(s)
- M I Banton
- a Gorge View Consulting LLC , Hood River , OR , USA
| | - J S Bus
- b Health Sciences , Exponent , Midland , MI , USA
| | - J J Collins
- c Health Sciences , Saginaw Valley State University , Saginaw , MI , USA
| | - E Delzell
- d Private consultant , Birmingham , AL , USA
| | | | - J E Kester
- f Kester Consulting LLC , Wentzville , MO , USA
| | | | - R Waites
- h Sabic , Innovative Plastics US LLC , Mount Vernon , IN , USA
| | - S S Sarang
- i Shell Health , Shell International , Houston , TX , USA
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Nettore IC, Colao A, Macchia PE. Nutritional and Environmental Factors in Thyroid Carcinogenesis. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:ijerph15081735. [PMID: 30104523 PMCID: PMC6121258 DOI: 10.3390/ijerph15081735] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 08/05/2018] [Accepted: 08/05/2018] [Indexed: 02/06/2023]
Abstract
Several epidemiological studies suggest an increased incidence of thyroid carcinoma (TC) in recent years, especially for the papillary histotype (PTC), suggesting that specific carcinogens might promote molecular abnormalities that are typical of PTC. The increased incidence is probably attributed to more intensive and sensitive diagnostic procedures, even if recent data suggest that various toxic elements could explain the phenomenon. Ionizing radiation exposure represents the most accepted risk factor for differentiated thyroid cancer that includes both the follicular and papillary histotypes. In this review, we examined the other environmental carcinogens that play a role in TC, such as eating habits, living in volcanic areas, and xenobiotic elements. Among eating habits, iodine intake represents one of the more discussed elements, because its deficiency is associated with follicular thyroid carcinomas (FTCs), while its progressive increment seems to be responsible for PTC. The gas, ash, and lava emissions of volcanoes are composed of various toxic compounds that pollute ground water, vegetables, and animals, contaminating humans via the food chain. Finally, the risk of developing PTC has also been associated with exposure of the population to xenobiotics in the environment or in the home. Their carcinogenic effects are probably caused by their accumulation, but additional studies are necessary to better understand the mechanisms of action.
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Affiliation(s)
| | - Annamaria Colao
- Dipartimento di Medicina Clinica e Chirurgia, Università di Napoli Federico II, 80138 Napoli NA, Italy.
| | - Paolo Emidio Macchia
- Dipartimento di Medicina Clinica e Chirurgia, Università di Napoli Federico II, 80138 Napoli NA, Italy.
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Medda E, Santini F, De Angelis S, Franzellin F, Fiumalbi C, Perico A, Gilardi E, Mechi MT, Marsili A, Citroni A, Leandri A, Mantovani A, Vitti P, Olivieri A. Iodine nutritional status and thyroid effects of exposure to ethylenebisdithiocarbamates. ENVIRONMENTAL RESEARCH 2017; 154:152-159. [PMID: 28073049 DOI: 10.1016/j.envres.2016.12.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 11/29/2016] [Accepted: 12/21/2016] [Indexed: 06/06/2023]
Abstract
INTRODUCTION Italy is still characterized by a mild iodine deficiency and is among the most intensive users of chemical products for agriculture in Europe. The aim of this study was i) to evaluate thyroid effects of exposure to mancozeb, a fungicide widely used in agriculture, in a sample of Italian grapevine workers, and ii) to verify whether the iodine intake may modulate the risk of thyroid disruption due to the mancozeb metabolite ethylenthiourea (ETU). METHODS One hundred seventy-seven occupationally exposed male workers (29 from Chianti, a mild iodine deficient area, and 148 from Bolzano an iodine sufficient province) and 74 non-occupationally exposed male controls (34 from Chianti and 40 from Bolzano) were enrolled in the study. Serum biomarkers of thyroid function, as well as urinary iodine and ETU concentrations were assessed. Moreover all the recruited subjects underwent clinical examination and thyroid ultrasound. RESULTS Multivariate comparisons showed lower mean serum levels of FT4 in Chianti-workers as compared to Bolzano-workers. Moreover, an increased urinary iodine excretion (>250µg/L) was more frequently found among more exposed workers (ETU>20µg/L) than among less exposed ones and this effect was more pronounced in Chianti- than in Bolzano-workers. Chianti-workers also showed a significantly higher frequency of very low thyroid volume (≤6.0ml) as compared to controls. CONCLUSIONS These findings showed a mild thyroid disrupting effect due to occupational exposure to mancozeb, more pronounced in workers residing in an area characterized by a mild to moderate iodine deficiency as compared to workers residing in an area covered by a long-lasting iodine prophylaxis program.
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Affiliation(s)
- Emanuela Medda
- National Centre for Epidemiology Surveillance and Health Promotion, Italian National Institute of Health, Viale Regina Elena 299, 00161 Rome, Italy
| | - Ferruccio Santini
- Endocrinology Unit, Azienda Ospedaliero Universitaria Pisana, Pisa, Italy
| | - Simona De Angelis
- Department of Cell Biology and Neuroscience, Italian National Institute of Health, Viale Regina Elena 299, 00161 Rome, Italy
| | | | | | | | - Enzo Gilardi
- Department of Cell Biology and Neuroscience, Italian National Institute of Health, Viale Regina Elena 299, 00161 Rome, Italy
| | | | - Alessandro Marsili
- Endocrinology Unit, Azienda Ospedaliero Universitaria Pisana, Pisa, Italy
| | | | | | - Alberto Mantovani
- Department of Food Safety and Veterinary Public Health, Italian National Institute of Health, Viale Regina Elena 299, 00161 Rome, Italy
| | - Paolo Vitti
- Endocrinology Unit, Azienda Ospedaliero Universitaria Pisana, Pisa, Italy
| | - Antonella Olivieri
- Department of Cell Biology and Neuroscience, Italian National Institute of Health, Viale Regina Elena 299, 00161 Rome, Italy.
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Benvenga S, Antonelli A, Vita R. Thyroid nodules and thyroid autoimmunity in the context of environmental pollution. Rev Endocr Metab Disord 2015; 16:319-40. [PMID: 26825072 DOI: 10.1007/s11154-016-9327-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Evidence suggests that in most industrialized countries autoimmune disorders, including chronic lymphocytic thyroiditis, are increasing. This increase parallels the one regarding differentiated thyroid cancer, the increment of which is mainly due to the papillary histotype. A number of studies have pointed to an association between chronic lymphocytic thyroiditis and differentiated thyroid cancer. The upward trend of these two thyroid diseases is sustained by certain environmental factors, such as polluting substances acting as endocrine disrupting chemicals. Herein we will review the experimental and clinical literature that highlights the effects of environmental and occupational exposure to polluting chemicals in the development of autoimmune thyroid disease or differentiated thyroid cancer. Stakeholders, starting from policymarkers, should become more sensitive to the consequences for the thyroid resulting from exposure to EDC. Indeed, the economic burden resulting from such consequences has not been quantified thus far.
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Affiliation(s)
- Salvatore Benvenga
- Department of Clinical and Experimental Medicine, University of Messina, Policlinico G. Martino, Padiglione H, 4 piano, via Consolare Valeria, 98125, Messina, Italy.
- Master Program on Childhood, Adolescent and Women's Endocrine Health, University of Messina School of Medicine, Messina, Italy.
- Interdepartmental Program of Molecular and Clinical Endocrinology, and Women's Endocrine Health, University Hospital Policlinico G. Martino, Messina, Italy.
| | - Alessandro Antonelli
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Roberto Vita
- Department of Clinical and Experimental Medicine, University of Messina, Policlinico G. Martino, Padiglione H, 4 piano, via Consolare Valeria, 98125, Messina, Italy
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Gelbke HP, Banton M, Leibold E, Pemberton M, Samson SL. A critical review finds styrene lacks direct endocrine disruptor activity. Crit Rev Toxicol 2015; 45:727-64. [PMID: 26406562 DOI: 10.3109/10408444.2015.1064091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The European Commission lists styrene (S) as an endocrine disruptor based primarily on reports of increased prolactin (PRL) levels in S-exposed workers. The US Environmental Protection Agency included S in its list of chemicals to be tested for endocrine activity. Therefore, the database of S for potential endocrine activity is assessed. In vitro and in vivo screening studies, as well as non-guideline and guideline investigations in experimental animals indicate that S is not associated with (anti)estrogenic, (anti)androgenic, or thyroid-modulating activity or with an endocrine activity that may be relevant for the environment. Studies in exposed workers have suggested elevated PRL levels that have been further examined in a series of human and animal investigations. While there is only one definitively known physiological function of PRL, namely stimulation of milk production, many normal stress situations may lead to elevations without any chemical exposure. Animal studies on various aspects of dopamine (DA), the PRL-regulating neurotransmitter, in the central nervous system did not give mechanistic explanations on how S may affect PRL levels. Overall, a neuroendocrine disruption of PRL regulation cannot be deduced from a large experimental database. The effects in workers could not consistently be reproduced in experimental animals and the findings in humans represented acute reversible effects clearly below clinical and pathological levels. Therefore, unspecific acute workplace-related stress is proposed as an alternative mode of action for elevated PRL levels in workers.
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Affiliation(s)
| | - Marcy Banton
- b Lyondell Chemical Company , Houston, Texas , USA
| | | | | | - Susan Leanne Samson
- e Division of Endocrinology, Department of Medicine , Baylor College of Medicine , Houston, Texas , USA
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Marcello MA, Malandrino P, Almeida JFM, Martins MB, Cunha LL, Bufalo NE, Pellegriti G, Ward LS. The influence of the environment on the development of thyroid tumors: a new appraisal. Endocr Relat Cancer 2014; 21:T235-54. [PMID: 24948559 DOI: 10.1530/erc-14-0131] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Most epidemiological studies concerning differentiated thyroid cancers (DTC) indicate an increasing incidence over the last two decades. This increase might be partially explained by the better access to health services worldwide, but clinicopathological analyses do not fully support this hypothesis, indicating that there are carcinogenetic factors behind this noticeable increasing incidence. Although we have undoubtedly understood the biology and molecular pathways underlying thyroid carcinogenesis in a better way, we have made very little progresses in identifying a risk profile for DTC, and our knowledge of risk factors is very similar to what we knew 30-40 years ago. In addition to ionizing radiation exposure, the most documented and established risk factor for DTC, we also investigated the role of other factors, including eating habits, tobacco smoking, living in a volcanic area, xenobiotics, and viruses, which could be involved in thyroid carcinogenesis, thus, contributing to the increase in DTC incidence rates observed.
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Affiliation(s)
- M A Marcello
- Laboratory of Cancer Molecular Genetics (Gemoca)Faculty of Medical Sciences, University of Campinas (FCM-Unicamp), Rua Tessalia Vieira de Camargo, 126, Barao Geraldo, Campinas, Sao Paulo, 13083-887, BrazilEndocrinologyDepartment of Clinical and Molecular Biomedicine, Garibaldi-Nesima Medical Center, University of Catania, Catania, Italy
| | - P Malandrino
- Laboratory of Cancer Molecular Genetics (Gemoca)Faculty of Medical Sciences, University of Campinas (FCM-Unicamp), Rua Tessalia Vieira de Camargo, 126, Barao Geraldo, Campinas, Sao Paulo, 13083-887, BrazilEndocrinologyDepartment of Clinical and Molecular Biomedicine, Garibaldi-Nesima Medical Center, University of Catania, Catania, Italy
| | - J F M Almeida
- Laboratory of Cancer Molecular Genetics (Gemoca)Faculty of Medical Sciences, University of Campinas (FCM-Unicamp), Rua Tessalia Vieira de Camargo, 126, Barao Geraldo, Campinas, Sao Paulo, 13083-887, BrazilEndocrinologyDepartment of Clinical and Molecular Biomedicine, Garibaldi-Nesima Medical Center, University of Catania, Catania, Italy
| | - M B Martins
- Laboratory of Cancer Molecular Genetics (Gemoca)Faculty of Medical Sciences, University of Campinas (FCM-Unicamp), Rua Tessalia Vieira de Camargo, 126, Barao Geraldo, Campinas, Sao Paulo, 13083-887, BrazilEndocrinologyDepartment of Clinical and Molecular Biomedicine, Garibaldi-Nesima Medical Center, University of Catania, Catania, Italy
| | - L L Cunha
- Laboratory of Cancer Molecular Genetics (Gemoca)Faculty of Medical Sciences, University of Campinas (FCM-Unicamp), Rua Tessalia Vieira de Camargo, 126, Barao Geraldo, Campinas, Sao Paulo, 13083-887, BrazilEndocrinologyDepartment of Clinical and Molecular Biomedicine, Garibaldi-Nesima Medical Center, University of Catania, Catania, Italy
| | - N E Bufalo
- Laboratory of Cancer Molecular Genetics (Gemoca)Faculty of Medical Sciences, University of Campinas (FCM-Unicamp), Rua Tessalia Vieira de Camargo, 126, Barao Geraldo, Campinas, Sao Paulo, 13083-887, BrazilEndocrinologyDepartment of Clinical and Molecular Biomedicine, Garibaldi-Nesima Medical Center, University of Catania, Catania, Italy
| | - G Pellegriti
- Laboratory of Cancer Molecular Genetics (Gemoca)Faculty of Medical Sciences, University of Campinas (FCM-Unicamp), Rua Tessalia Vieira de Camargo, 126, Barao Geraldo, Campinas, Sao Paulo, 13083-887, BrazilEndocrinologyDepartment of Clinical and Molecular Biomedicine, Garibaldi-Nesima Medical Center, University of Catania, Catania, Italy
| | - L S Ward
- Laboratory of Cancer Molecular Genetics (Gemoca)Faculty of Medical Sciences, University of Campinas (FCM-Unicamp), Rua Tessalia Vieira de Camargo, 126, Barao Geraldo, Campinas, Sao Paulo, 13083-887, BrazilEndocrinologyDepartment of Clinical and Molecular Biomedicine, Garibaldi-Nesima Medical Center, University of Catania, Catania, Italy
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Hartoft-Nielsen ML, Boas M, Bliddal S, Rasmussen AK, Main K, Feldt-Rasmussen U. Do Thyroid Disrupting Chemicals Influence Foetal Development during Pregnancy? J Thyroid Res 2011; 2011:342189. [PMID: 21918727 PMCID: PMC3170895 DOI: 10.4061/2011/342189] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Revised: 05/13/2011] [Accepted: 06/02/2011] [Indexed: 11/20/2022] Open
Abstract
Maternal euthyroidism during pregnancy is crucial for normal development and, in particular, neurodevelopment of the foetus. Up to 3.5 percent of pregnant women suffer from hypothyroidism. Industrial use of various chemicals—endocrine disrupting chemicals (EDCs)—has been shown to cause almost constant exposure of humans with possible harmful influence on health and hormone regulation. EDCs may affect thyroid hormone homeostasis by different mechanisms, and though the effect of each chemical seems scarce, the added effects may cause inappropriate consequences on, for example, foetal neurodevelopment.
This paper focuses on thyroid hormone influence on foetal development in relation to the chemicals suspected of thyroid disrupting properties with possible interactions with maternal thyroid homeostasis. Knowledge of the effects is expected to impact the general debate on the use of these chemicals. However, more studies are needed to elucidate the issue, since human studies are scarce.
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Affiliation(s)
- Marie-Louise Hartoft-Nielsen
- Department of Medical Endocrinology PE-2131, Rigshospitalet, University Hospital of Copenhagen, 2100 Copenhagen, Denmark
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Abstract
Common environmental exposures may affect thyroid function in humans. Foetuses and infants are most vulnerable to these effects because they need thyroid hormone for normal neurodevelopment. Perchlorate, thiocyanate and nitrate are all competitive inhibitors of the sodium/iodine symporter (NIS) in pharmacologic doses, but their effects on human thyroid function at environmental exposure levels remain unclear. Many compounds, including polychlorinated biphenyls (PCBs), polybrominated diphenylethers (PBDEs), bisphenol-A (BPA) and triclosan, may have direct actions on the thyroid hormone receptor, but these effects are complex and are not yet well understood. Isoflavones inhibit thyroperoxidase (TPO) activity, and, therefore, may cause goitre and hypothyroidism if ingested at high levels, particularly in iodine-deficient individuals. Organochlorine pesticides and dioxins may decrease serum T(4) half-life by activating hepatic enzymes. Additional studies are needed to further elucidate the risk posed by these and other potentially thyroid-disrupting compounds.
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Affiliation(s)
- Elizabeth N Pearce
- Section of Endocrinology, Diabetes, and Nutrition, Boston University Medical Center, 88 East Newton street, Evans 201, Boston, MA 02118, USA.
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Current World Literature. Curr Opin Endocrinol Diabetes Obes 2009; 16:401-5. [PMID: 19687666 DOI: 10.1097/med.0b013e32833118e2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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