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Paustenbach DJ, Brown SE, Heywood JJ, Donnell MT, Eaton DL. Risk characterization of N-nitrosodimethylamine in pharmaceuticals. Food Chem Toxicol 2024; 186:114498. [PMID: 38341171 DOI: 10.1016/j.fct.2024.114498] [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: 09/28/2023] [Revised: 01/23/2024] [Accepted: 01/31/2024] [Indexed: 02/12/2024]
Abstract
Since 2018, N-nitrosodimethylamine (NDMA) has been a reported contaminant in numerous pharmaceutical products. To guide the pharmaceutical industry, FDA identified an acceptable intake (AI) of 96 ng/day NDMA. The approach assumed a linear extrapolation from the Carcinogenic Potency Database (CPDB) harmonic-mean TD50 identified in chronic studies in rats. Although NDMA has been thought to act as a mutagenic carcinogen in experimental animals, it has not been classified as a known human carcinogen by any regulatory agency. Humans are exposed to high daily exogenous and endogenous doses of NDMA. Due to the likelihood of a threshold dose for NDMA-related tumors in animals, we believe that there is ample scientific basis to utilize the threshold-based benchmark dose or point-of-departure (POD) approach when estimating a Permissible Daily Exposure limit (PDE) for NDMA. We estimated that 29,000 ng/kg/day was an appropriate POD for calculating a PDE. Assuming an average bodyweight of 50 kg, we expect that human exposures to NDMA at doses below 5800 ng/day in pharmaceuticals would not result in an increased risk of liver cancer, and that there is little, if any, risk for any other type of cancer, when accounting for the mode-of-action in humans.
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Affiliation(s)
- D J Paustenbach
- Paustenbach and Associates, 970 West Broadway, Suite E, Jackson, WY, USA
| | - S E Brown
- Paustenbach and Associates, 207 Canyon Blvd, Boulder, CO, USA.
| | - J J Heywood
- Paustenbach and Associates, 207 Canyon Blvd, Boulder, CO, USA
| | - M T Donnell
- Valeo Sciences LLC, 333 Corporate Drive, Suite 130, Ladera Ranch, CA, USA
| | - D L Eaton
- Professor Emeritus, Department of Environmental & Occupational Health Sciences, University of Washington, Seattle, WA, USA
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2
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Malamardi S, Lambert K, Siddaiah JB, Erbas B, Mahesh PA. Effects of Ambient Air Pollutants on Hospital Admissions among Children Due to Asthma and Wheezing-Associated Lower Respiratory Infections in Mysore, India: A Time Series Study. CHILDREN (BASEL, SWITZERLAND) 2023; 10:1322. [PMID: 37628320 PMCID: PMC10453753 DOI: 10.3390/children10081322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 07/14/2023] [Accepted: 07/20/2023] [Indexed: 08/27/2023]
Abstract
Air pollutants are known to trigger asthma and wheezing-associated lower respiratory infections in children, but evidence regarding their effect on hospital admissions in India is limited. We conducted a time-series study over a period of five years to assess the role of ambient air pollutants in daily asthma-related hospital admissions in children in Mysore, India. Daily asthma and wheeze (associated with lower respiratory infections) admissions were modelled using a generalised additive model (GAM) to examine the non-linear effects and generalised linear models (GLM) for linear effects, if any. Models were adjusted by day of the week and lag days, with smooth terms for time, maximum temperature, and relative humidity, and they were stratified by sex and age group. Of the 362 children admitted, more than 50% were boys, and the mean age was 5.34 years (±4.66). The GAMs showed non-linear associations between NO2, PM2.5, and NH3. For example, a 10 µgm-3 (or 10%) increase in NO2 increased admissions by 2.42. These non-linear effects were more pronounced in boys. A linear effect was detected for PM10 with a relative risk (95% CI) of 1.028, 1.013, and 1.043 with admission. Further research is needed to explore whether these findings can be replicated in different cities in India. Air pollution needs to be controlled, and policies that focus on lower cut-off levels for vulnerable populations are necessary.
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Affiliation(s)
- Sowmya Malamardi
- Department of Public Health, School of Psychology & Public Health, College of Science Health and Engineering, La Trobe University, Melbourne, VIC 3083, Australia; (S.M.); (K.L.); (B.E.)
| | - Katrina Lambert
- Department of Public Health, School of Psychology & Public Health, College of Science Health and Engineering, La Trobe University, Melbourne, VIC 3083, Australia; (S.M.); (K.L.); (B.E.)
| | - Jayaraj Biligere Siddaiah
- Department of Respiratory Medicine, JSS Academy of Higher Education & Research (JSSAHER), JSS Medical College, Mysore 570015, Karnataka, India;
| | - Bircan Erbas
- Department of Public Health, School of Psychology & Public Health, College of Science Health and Engineering, La Trobe University, Melbourne, VIC 3083, Australia; (S.M.); (K.L.); (B.E.)
| | - Padukudru Anand Mahesh
- Department of Respiratory Medicine, JSS Academy of Higher Education & Research (JSSAHER), JSS Medical College, Mysore 570015, Karnataka, India;
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3
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Dourson ML. Probabilistic methods for non-cancer health effects. Regul Toxicol Pharmacol 2023:105411. [PMID: 37295488 DOI: 10.1016/j.yrtph.2023.105411] [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: 03/30/2023] [Revised: 05/17/2023] [Accepted: 05/19/2023] [Indexed: 06/12/2023]
Abstract
Noncancer risk assessment methods and harmonization with cancer assessment methods have advanced from the simple divide a No Observed Adverse Effect Level (NOAEL) by a default safety factor or a linear extrapolation to background of the early 1980's. This advance is due in part due to groups such as the American Industrial Health Council, the National Institute of Environmental Health Sciences, the Society for Risk Analysis, the Society of Toxicology, and the U.S. Environmental Protection Agency (Bogdanffy et al., 2001), the National Academy of Sciences (1983 and 2009), the International Programme on Chemical Safety (2005, 2009), and to many independent researchers outside of and within a workshop series sponsored by the Alliance for Risk Assessment (ARA, 2023) prompted by the NAS (2009). Several of the case studies from this workshop series, and earlier work such as Bogdanffy et al. (2001), demonstrate that the dose response assessment of non-cancer toxicity and the harmonization of cancer and non-cancer methods are more than just a simple reflection of treating all non-cancer toxicity as if it has a threshold, or all cancer toxicity as if it did not. Moreover, one recommendation of NAS (2009) was to develop a problem formulation with risk managers prior to conducting any risk assessment. If the development of this problem formulation only necessitates the determination of a safe, or virtually safe dose, then the estimation of a Reference Dose (RfD) or virtually safe dose (VSD) or similar constructs should be encouraged. Not all of our environmental problems need a precise quantitative solution.
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Affiliation(s)
- Michael L Dourson
- Toxicology Excellence for Risk Assessment, 4303 Kirby Avenue, Cincinnati, OH, 45223, USA.
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4
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Linear non-threshold (LNT) fails numerous toxicological stress tests: Implications for continued policy use. Chem Biol Interact 2022; 365:110064. [DOI: 10.1016/j.cbi.2022.110064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 06/24/2022] [Accepted: 07/18/2022] [Indexed: 11/16/2022]
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5
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Li D, Li L. Human Chemical Exposure from Background Emissions in the United States and the Implication for Quantifying Risks from Marginal Emission Increase. TOXICS 2021; 9:308. [PMID: 34822699 PMCID: PMC8621763 DOI: 10.3390/toxics9110308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 11/08/2021] [Accepted: 11/12/2021] [Indexed: 11/16/2022]
Abstract
The linear dose-response relationship has long been assumed in assessments of health risk from an incremental chemical emission relative to background emissions. In this study, we systematically examine the relevancy of such an assumption with real-world data. We used the reported emission data, as background emissions, from the 2017 U.S. National Emission Inventory for 95 organic chemicals to estimate the central tendencies of exposures of the general U.S. population. Previously published nonlinear dose-response relationships for chemicals were used to estimate health risk from exposure. We also explored and identified four intervals of exposure in which the nonlinear dose-response relationship may be linearly approximated with fixed slopes. Predicted rates of exposure to these 95 chemicals are all within the lowest of the four intervals and associated with low health risk. The health risk may be overestimated if a slope on the dose-response relationship extrapolated from toxicological assays based on high response rates is used for a marginal increase in emission not substantially higher than background emissions. To improve the confidence of human health risk estimates for chemicals, future efforts should focus on deriving a more accurate dose-response relationship at lower response rates and interface it with exposure assessments.
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Affiliation(s)
| | - Li Li
- Correspondence: (D.L.); (L.L.)
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6
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Tsuji JS, Lennox KP, Watson HN, Chang ET. Essential concepts for interpreting the dose-response of low-level arsenic exposure in epidemiological studies. Toxicology 2021; 457:152801. [PMID: 33905760 DOI: 10.1016/j.tox.2021.152801] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 04/20/2021] [Accepted: 04/22/2021] [Indexed: 11/25/2022]
Abstract
Scientifically robust selections of epidemiological studies and assessments of the dose-response of inorganic arsenic in the low-dose range must consider key issues specific to arsenic in order to reduce risk of bias. The abundance of toxicological, mechanistic, and epidemiological evidence on arsenic enables a nuanced assessment of risk of bias in epidemiological studies of low-level arsenic, as opposed to a generic evaluation based only on standard principles. Important concepts in this context include 1) arsenic metabolism and mode of action for toxicity and carcinogenicity; 2) effects of confounding factors such as diet, health status including nutritional deficiencies, use of tobacco and other substances, and body composition; 3) strengths and limitations of various metrics for assessing relevant exposures consistent with the mode of action; and 4) the potential for bias in the positive direction for the observed dose-response relationship as exposure increases in the low-dose range. As an example, evaluation of a recent dose-response modeling using eight epidemiological studies of inorganic arsenic and bladder cancer demonstrated that the pooled risk estimate was markedly affected by the single study that was ranked as having a high risk of bias, based on the above factors. The other seven studies were also affected by these factors to varying, albeit lesser, degrees that can influence the apparent dose-response in the low-dose range (i.e., drinking water concentration of 65 µg/L or dose of approximately ≤1 µg/kg-day). These issues are relevant considerations for assessing health risks of oral exposures to inorganic arsenic in the U.S. population, and setting evidence-based regulatory limits to protect human health.
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Cohen JM, Beck BD, Rhomberg LR. Historical perspective on the role of cell proliferation in carcinogenesis for DNA-reactive and non-DNA-reactive carcinogens: Arsenic as an example. Toxicology 2021; 456:152783. [PMID: 33872731 DOI: 10.1016/j.tox.2021.152783] [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] [Received: 01/29/2021] [Revised: 04/07/2021] [Accepted: 04/11/2021] [Indexed: 10/21/2022]
Abstract
Our understanding of the etiology of cancer has developed significantly over the past fifty years, beginning with a single-hit linear no-threshold (LNT) conceptual model based on early studies conducted in Drosophila. Over the past several decades, multiple lines of evidence have accumulated to support a contemporary model of chemical carcinogenesis: a multi-hit model involving a prolonged stress environment that over time may drive the mutation of multiple cells into an injured state that ultimately could lead to uncontrolled proliferation via clonal expansion of mutation-carrying daughter cells. Arsenic carcinogenicity offers a useful case study for further exploration of advanced conceptual models for chemical carcinogenesis. A threshold for arsenic carcinogenicity is supported by its mode of action, characterized by repeating cycles of cytotoxicity and cellular regeneration. Furthermore, preliminary meta-analyses of epidemiology dose-response data for inorganic arsenic (iAs) and bladder cancer, correlated to dose-response data measured in vitro, support a threshold of effect in humans on the order of 50-100 μg/L in drinking water. In light of recent developments in our understanding of cancer etiology, we urge strong consideration of the existing mode-of-action evidence supporting a threshold of effect for arsenic carcinogenicity, as well as consideration of the potential methodological pitfalls in evaluating epidemiology dose-response data that could potentially bias in the direction of low-dose linearity.
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8
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Rider CV, McHale CM, Webster TF, Lowe L, Goodson WH, La Merrill MA, Rice G, Zeise L, Zhang L, Smith MT. Using the Key Characteristics of Carcinogens to Develop Research on Chemical Mixtures and Cancer. ENVIRONMENTAL HEALTH PERSPECTIVES 2021; 129:35003. [PMID: 33784186 PMCID: PMC8009606 DOI: 10.1289/ehp8525] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 02/19/2021] [Accepted: 03/10/2021] [Indexed: 05/09/2023]
Abstract
BACKGROUND People are exposed to numerous chemicals throughout their lifetimes. Many of these chemicals display one or more of the key characteristics of carcinogens or interact with processes described in the hallmarks of cancer. Therefore, evaluating the effects of chemical mixtures on cancer development is an important pursuit. Challenges involved in designing research studies to evaluate the joint action of chemicals on cancer risk include the time taken to perform the experiments because of the long latency and choosing an appropriate experimental design. OBJECTIVES The objectives of this work are to present the case for developing a research program on mixtures of environmental chemicals and cancer risk and describe recommended approaches. METHODS A working group comprising the coauthors focused attention on the design of mixtures studies to inform cancer risk assessment as part of a larger effort to refine the key characteristics of carcinogens and explore their application. Working group members reviewed the key characteristics of carcinogens, hallmarks of cancer, and mixtures research for other disease end points. The group discussed options for developing tractable projects to evaluate the joint effects of environmental chemicals on cancer development. RESULTS AND DISCUSSION Three approaches for developing a research program to evaluate the effects of mixtures on cancer development were proposed: a chemical screening approach, a transgenic model-based approach, and a disease-centered approach. Advantages and disadvantages of each are discussed. https://doi.org/10.1289/EHP8525.
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Affiliation(s)
- Cynthia V. Rider
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Cliona M. McHale
- Division of Environmental Health Sciences, University of California Berkeley, School of Public Health, Berkeley, California, USA
| | - Thomas F. Webster
- Department of Environmental Health, School of Public Health, Boston University, Boston, Massachusetts, USA
| | - Leroy Lowe
- Getting to Know Cancer (NGO), Truro, Nova Scotia, Canada
| | - William H. Goodson
- Department of Surgery, California Pacific Medical Center Research Institute, San Francisco, California, USA
| | - Michele A. La Merrill
- Department of Environmental Toxicology, University of California Davis, Davis, California, USA
| | - Glenn Rice
- Office of Research & Development, Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Cincinnati, Ohio, USA
| | - Lauren Zeise
- Office of the Director, Office of Environmental Health and Hazard Assessment, California Environmental Protection Agency, Sacramento, California, USA
| | - Luoping Zhang
- Division of Environmental Health Sciences, University of California Berkeley, School of Public Health, Berkeley, California, USA
| | - Martyn T. Smith
- Division of Environmental Health Sciences, University of California Berkeley, School of Public Health, Berkeley, California, USA
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9
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Cox LA. Implications of nonlinearity, confounding, and interactions for estimating exposure concentration-response functions in quantitative risk analysis. ENVIRONMENTAL RESEARCH 2020; 187:109638. [PMID: 32450424 PMCID: PMC7235595 DOI: 10.1016/j.envres.2020.109638] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 05/04/2020] [Accepted: 05/05/2020] [Indexed: 05/04/2023]
Abstract
Recent advances in understanding of biological mechanisms and adverse outcome pathways for many exposure-related diseases show that certain common mechanisms involve thresholds and nonlinearities in biological exposure concentration-response (C-R) functions. These range from ultrasensitive molecular switches in signaling pathways, to assembly and activation of inflammasomes, to rupture of lysosomes and pyroptosis of cells. Realistic dose-response modeling and risk analysis must confront the reality of nonlinear C-R functions. This paper reviews several challenges for traditional statistical regression modeling of C-R functions with thresholds and nonlinearities, together with methods for overcoming them. Statistically significantly positive exposure-response regression coefficients can arise from many non-causal sources such as model specification errors, incompletely controlled confounding, exposure estimation errors, attribution of interactions to factors, associations among explanatory variables, or coincident historical trends. If so, the unadjusted regression coefficients do not necessarily predict how or whether reducing exposure would reduce risk. We discuss statistical options for controlling for such threats, and advocate causal Bayesian networks and dynamic simulation models as potentially valuable complements to nonparametric regression modeling for assessing causally interpretable nonlinear C-R functions and understanding how time patterns of exposures affect risk. We conclude that these approaches are promising for extending the great advances made in statistical C-R modeling methods in recent decades to clarify how to design regulations that are more causally effective in protecting human health.
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10
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Brescia S. Thresholds of adversity and their applicability to endocrine disrupting chemicals. Crit Rev Toxicol 2020; 50:213-218. [PMID: 32228218 DOI: 10.1080/10408444.2020.1740973] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Within the European Union, various legislative acts contain specific provisions on endocrine disruption, requiring the regulation of substances with endocrine disrupting properties via a hazard-based approach. Presumably this is due to an assumed lack of thresholds for the adverse effects of such substances. Conversely, in other jurisdictions, such as USA, Canada, Australia and Japan, endocrine disruptors (EDs) are regulated using a risk-based approach. As a consequence, in recent years there has been increasing controversy on whether thresholds can be inferred for endocrine-mediated effects. There is concern that the endocrine system is too complex to allow estimation of safe levels of exposure to such chemicals. This brief review aims to evaluate the available scientific evidence in this area and offer a sound and robust conclusion supported by this analysis. It is concluded that there is nothing special or unique about endocrine disruption or greater uncertainties in its assessment compared to other non-genotoxic forms of toxicity to justify adopting a non-threshold approach by default. Biology predicts that thresholds of adversity exist and are the rule for all endpoints, including those arising from endocrine disruption. A threshold approach to the risk assessment of endocrine disrupting chemicals is scientifically justified.
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Affiliation(s)
- Susy Brescia
- Health and Safety Executive (HSE), Chemicals Regulation Division (CRD), Merseyside, UK
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11
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Tsuji JS, Chang ET, Gentry PR, Clewell HJ, Boffetta P, Cohen SM. Dose-response for assessing the cancer risk of inorganic arsenic in drinking water: the scientific basis for use of a threshold approach. Crit Rev Toxicol 2019; 49:36-84. [DOI: 10.1080/10408444.2019.1573804] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
| | - Ellen T. Chang
- Exponent, Inc., Menlo Park, CA and Stanford Cancer Institute, Stanford, CA, USA
| | | | | | - Paolo Boffetta
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Samuel M. Cohen
- Havlik-Wall Professor of Oncology, Department of Pathology and Microbiology and the Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
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12
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Buchholz BA, Carratt SA, Kuhn EA, Collette NM, Ding X, Van Winkle LS. Naphthalene DNA Adduct Formation and Tolerance in the Lung. NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH. SECTION B, BEAM INTERACTIONS WITH MATERIALS AND ATOMS 2019; 438:119-123. [PMID: 30631217 PMCID: PMC6322674 DOI: 10.1016/j.nimb.2018.07.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Naphthalene (NA) is a respiratory toxicant and possible human carcinogen. NA is a ubiquitous combustion product and significant component of jet fuel. The National Toxicology Program found that NA forms tumors in two species, in rats (nose) and mice (lung). However, it has been argued that NA does not pose a cancer risk to humans because NA is bioactivated by cytochrome P450 monooxygenase enzymes that have very high efficiency in the lung tissue of rodents but low efficiency in the lung tissue of humans. It is thought that NA carcinogenesis in rodents is related to repeated cycles of lung epithelial injury and repair, an indirect mechanism. Repeated in vivo exposure to NA leads to development of tolerance, with the emergence of cells more resistant to NA insult. We tested the hypothesis that tolerance involves reduced susceptibility to the formation of NA-DNA adducts. NA-DNA adduct formation in tolerant mice was examined in individual, metabolically-active mouse airways exposed ex vivo to 250 μΜ 14C-NA. Ex vivo dosing was used since it had been done previously and the act of creating a radioactive aerosol of a potential carcinogen posed too many safety and regulatory obstacles. Following extensive rinsing to remove unbound 14C-NA, DNA was extracted and 14C-NA-DNA adducts were quantified by AMS. The tolerant mice appeared to have slightly lower NA-DNA adduct levels than non-tolerant controls, but intra-group variations were large and the difference was statistically insignificant. It appears the tolerance may be more related to other mechanisms, such as NA-protein interactions in the airway, than DNA-adduct formation.
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Affiliation(s)
- Bruce A Buchholz
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA USA
| | - Sarah A Carratt
- Center for Health and the Environment, University of California, Davis, CA USA
| | - Edward A Kuhn
- Bioscience and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA USA
| | - Nicole M Collette
- Bioscience and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA USA
| | - Xinxin Ding
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ USA
| | - Laura S Van Winkle
- Center for Health and the Environment, University of California, Davis, CA USA
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13
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Calabrese EJ. The additive to background assumption in cancer risk assessment: A reappraisal. ENVIRONMENTAL RESEARCH 2018; 166:175-204. [PMID: 29890424 DOI: 10.1016/j.envres.2018.05.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 05/08/2018] [Accepted: 05/11/2018] [Indexed: 05/21/2023]
Abstract
The assumption that chemical and radiation induced cancers act in a manner that is additive to background was proposed in the mid-1970s. It was adopted by the U.S. Environmental Protection Agency (EPA) in 1986 and then subsequently by other regulatory agencies worldwide for cancer risk assessment. It ensured that cancer risks at low doses act in a linear fashion. The additive to background process assumes that the mechanism(s) resulting in induced (i.e., treatment related) and spontaneous (i.e., control group) cancers are identical. This assumption could not be properly evaluated due to inadequate mechanistic data when it was proposed in the 1970s. Using the findings of modern molecular toxicology, including oncogene activation/mutation, gene regulation, and molecular pathway analyses, the additive to background assumption was evaluated in the present paper. Based on published studies with 45 carcinogens over 13 diverse mammalian models and for a broad range of tumor types compelling evidence indicates that carcinogen-induced tumors are mediated in general via mechanisms that are not identical to those affecting the occurrence of the same type of spontaneous tumors in appropriate control groups. These findings, which challenge a fundamental assumption of the additive to background concept, have significant implications for cancer risk assessment policy, regulatory agency practices, as well as fundamental concepts of cancer biology.
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Affiliation(s)
- Edward J Calabrese
- Department of Environmental Health Sciences, University of Massachusetts, Morrill I, N344, Amherst, MA 01003, United States.
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14
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Lange SS, Mulholland SE, Honeycutt ME. What Are the Net Benefits of Reducing the Ozone Standard to 65 ppb? An Alternative Analysis. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:ijerph15081586. [PMID: 30049975 PMCID: PMC6121288 DOI: 10.3390/ijerph15081586] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 07/19/2018] [Accepted: 07/21/2018] [Indexed: 12/14/2022]
Abstract
In October 2015, the United States Environmental Protection Agency (EPA) lowered the level of the ozone National Ambient Air Quality Standard (NAAQS) from 0.075 ppm to 0.070 ppm (annual 4th highest daily maximum 8-h concentration, averaged over three years). The EPA estimated a 2025 annual national non-California net benefit of $1.5 to $4.5 billion (2011$, 7% discount rate) for a 0.070 ppm standard, and a −$1.0 to $14 billion net benefit for an alternative 0.065 ppm standard. The purpose of this work is to present a combined toxicological and economic assessment of the EPA’s benefit-cost analysis of the 2015 ozone NAAQS. Assessing the quality of the epidemiology studies based on considerations of bias, confounding, chance, integration of evidence, and application of the studies for future population risk estimates, we derived several alternative benefits estimates. We also considered the strengths and weaknesses of the EPA’s cost estimates (e.g., marginal abatement costs), as well as estimates completed by other authors, and provided our own alternative cost estimate. Based on our alternative benefits and cost calculations, we estimated an alternative net benefit of between −$0.3 and $1.8 billion for a 0.070 ppm standard (2011 $, 7% discount rate) and between −$23 and −$17 billion for a 0.065 ppm standard. This work demonstrates that alternative reasonable assumptions can generate very difference cost and benefits estimates that may impact how policy makers view the outcomes of a major rule.
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Affiliation(s)
- Sabine S Lange
- Toxicology Division, Texas Commission on Environmental Quality, P.O. Box 13087, MC-168, Austin, TX 78711, USA.
| | - Sean E Mulholland
- Department of Economics, Management, and Project Management, West Carolina University, Cullowhee, NC 28723, USA.
| | - Michael E Honeycutt
- Toxicology Division, Texas Commission on Environmental Quality, P.O. Box 13087, MC-168, Austin, TX 78711, USA.
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15
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Endocrine Disruption: Current approaches for regulatory testing and assessment of plant protection products are fit for purpose. Toxicol Lett 2018; 296:10-22. [PMID: 30006252 DOI: 10.1016/j.toxlet.2018.07.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 07/06/2018] [Accepted: 07/09/2018] [Indexed: 11/23/2022]
Abstract
The ongoing debate concerning the regulation of endocrine disruptors, has increasingly led to questions concerning the current testing of chemicals and whether this is adequate for the assessment of potential endocrine disrupting effects. This paper describes the current testing approaches for plant protection product (PPP) active substances in the European Union and the United States and how they relate to the assessment of endocrine disrupting properties for human and environmental health. This includes a discussion of whether the current testing approaches cover modalities other than the estrogen, androgen, thyroid and steroidogenesis (EATS) pathways, sensitive windows of exposure, adequate assessment of human endocrine disorders and wildlife species, and the determination of thresholds for endocrine disruption. It is concluded, that the scope and nature of the core and triggered data requirements for PPP active substances are scientifically robust to address adverse effects mediated through endocrine mode(s) of action and to characterise these effects in terms of dose response.
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16
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Haber LT, Dourson ML, Allen BC, Hertzberg RC, Parker A, Vincent MJ, Maier A, Boobis AR. Benchmark dose (BMD) modeling: current practice, issues, and challenges. Crit Rev Toxicol 2018. [PMID: 29516780 DOI: 10.1080/10408444.2018.1430121] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Benchmark dose (BMD) modeling is now the state of the science for determining the point of departure for risk assessment. Key advantages include the fact that the modeling takes account of all of the data for a particular effect from a particular experiment, increased consistency, and better accounting for statistical uncertainties. Despite these strong advantages, disagreements remain as to several specific aspects of the modeling, including differences in the recommendations of the US Environmental Protection Agency (US EPA) and the European Food Safety Authority (EFSA). Differences exist in the choice of the benchmark response (BMR) for continuous data, the use of unrestricted models, and the mathematical models used; these can lead to differences in the final BMDL. It is important to take confidence in the model into account in choosing the BMDL, rather than simply choosing the lowest value. The field is moving in the direction of model averaging, which will avoid many of the challenges of choosing a single best model when the underlying biology does not suggest one, but additional research would be useful into methods of incorporating biological considerations into the weights used in the averaging. Additional research is also needed regarding the interplay between the BMR and the UF to ensure appropriate use for studies supporting a lower BMR than default values, such as for epidemiology data. Addressing these issues will aid in harmonizing methods and moving the field of risk assessment forward.
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Affiliation(s)
- Lynne T Haber
- a Risk Science Center , University of Cincinnati , Cincinnati , OH , USA
| | - Michael L Dourson
- a Risk Science Center , University of Cincinnati , Cincinnati , OH , USA
| | | | - Richard C Hertzberg
- c Department of Environmental Health , Emory University , Atlanta , GA , USA
| | - Ann Parker
- a Risk Science Center , University of Cincinnati , Cincinnati , OH , USA
| | - Melissa J Vincent
- a Risk Science Center , University of Cincinnati , Cincinnati , OH , USA
| | - Andrew Maier
- a Risk Science Center , University of Cincinnati , Cincinnati , OH , USA
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Saracci R. The hazards of hazard identification in environmental epidemiology. Environ Health 2017; 16:85. [PMID: 28793913 PMCID: PMC5550949 DOI: 10.1186/s12940-017-0296-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 08/02/2017] [Indexed: 06/07/2023]
Abstract
Hazard identification is a major scientific challenge, notably for environmental epidemiology, and is often surrounded, as the recent case of glyphosate shows, by debate arising in the first place by the inherently problematic nature of many components of the identification process. Particularly relevant in this respect are components less amenable to logical or mathematical formalization and essentially dependent on scientists' judgment. Four such potentially hazardous components that are capable of distorting the correct process of hazard identification are reviewed and discussed from an epidemiologist perspective: (1) lexical mix-up of hazard and risk (2) scientific questions as distinct from testable hypotheses, and implications for the hierarchy of strength of evidence obtainable from different types of study designs (3) assumptions in prior beliefs and model choices and (4) conflicts of interest. Four suggestions are put forward to strengthen a process that remains in several aspects judgmental, but not arbitrary, in nature.
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Parrott JL, Bjerregaard P, Brugger KE, Gray LE, Iguchi T, Kadlec SM, Weltje L, Wheeler JR. Uncertainties in biological responses that influence hazard and risk approaches to the regulation of endocrine active substances. INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT 2017; 13:293-301. [PMID: 27862884 PMCID: PMC8215718 DOI: 10.1002/ieam.1866] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 09/19/2016] [Accepted: 11/09/2016] [Indexed: 05/18/2023]
Abstract
Endocrine-disrupting substances (EDS) may have certain biological effects including delayed effects, multigenerational effects, and may display nonmonotonic dose-response (NMDR) relationships that require careful consideration when determining environmental hazards. Endocrine disrupting substances can have specific and profound effects when exposure occurs during sensitive windows of the life cycle (development, reproduction). This creates the potential for delayed effects that manifest when exposure has ceased, possibly in a different life stage. This potential underscores the need for testing in appropriate (sensitive) life stages and full life cycle designs. Such tests are available in the Organisation for Economic Co-operation and Development (OECD) tool box and should be used to derive endpoints that can be considered protective of all life stages. Similarly, the potential for effects to be manifest in subsequent generations (multigenerational effects) has also been raised as a potential issue in the derivation of appropriate endpoints for EDS. However, multigenerational studies showing increasing sensitivity of successive generations are uncommon. Indeed this is reflected in the design of new higher tier tests to assess endocrine active substances (EAS) that move to extended one-generation designs and away from multi-generational studies. The occurrence of NMDRs is also considered a limiting factor for reliable risk assessment of EDS. Evidence to date indicates NMDRs are more prevalent in in vitro and mechanistic data, not often translating to adverse apical endpoints that would be used in risk assessment. A series of steps to evaluate NMDRs in the context of endocrine hazard and risk assessment procedures is presented. If careful consideration of delayed, multigenerational effects and NMDRs is made, it is feasible to assess environmental endocrine hazards and derive robust apical endpoints for risk assessment procedures ensuring a high level of environmental protection. Integr Environ Assess Manag 2017;13:293-301. © 2016 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).
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Affiliation(s)
- Joanne L Parrott
- Environment and Climate Change Canada, Burlington, Ontario, Canada
- Address correspondence to
| | - Poul Bjerregaard
- Department of Biology, University of Southern Denmark, Odense, Denmark
| | - Kristin E Brugger
- DuPont Crop Protection, Stine-Haskell Research Center, Newark, New Jersey, USA
| | - L Earl Gray
- USEPA, Reproductive Toxicology Branch, Office of Research and Development, Research Triangle Park, North Carolina
| | - Taisen Iguchi
- Department of Bioenvironmental Research, Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, National Institutes of Natural Sciences, Okazaki, Japan
| | - Sarah M Kadlec
- University of Minnesota, Integrated Biosciences Graduate Program, Duluth, Minnesota, USA
| | - Lennart Weltje
- BASF SE, Crop Protection-Ecotoxicology, Limburgerhof, Germany
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19
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Trans fatty acids and cholesterol levels: An evidence map of the available science. Food Chem Toxicol 2016; 98:269-281. [PMID: 27394654 DOI: 10.1016/j.fct.2016.07.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 07/01/2016] [Accepted: 07/04/2016] [Indexed: 01/01/2023]
Abstract
High intakes of industrial trans fatty acids (iTFA) increase circulating low density lipoprotein cholesterol (LDL-C) levels, which has implicated iTFA in coronary heart disease (CHD) risk. Published data on iTFA and LDL-C, however, represent higher intake levels than the U.S. population currently consume. This study used state-of-the-art evidence mapping approaches to characterize the full body of literature on LDL-C and iTFA at low intake levels. A total of 32 independent clinical trials that included at least one intervention or control group with iTFA at ≤3%en were found. Findings indicated that a wide range of oils and interventions were used, limiting the ability to determine an isolated effect of iTFA intake. Few data points were found for iTFA at <3%en, with the majority of low-level exposures actually representing control group interventions containing non-partially hydrogenated (PHO) oils. Further, it appears that few dose-response data points are available to assess the relationship of low levels of iTFA, particularly from PHO exposure, and LDL-C. Therefore, limited evidence is available to determine the effect of iTFA at current consumption levels on CHD risk.
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Perharič L, Fatur T, Drofenik J. European Union's strategy on endocrine disrupting chemicals and the current position of Slovenia. Arh Hig Rada Toksikol 2016; 67:99-105. [PMID: 27331297 DOI: 10.1515/aiht-2016-67-2728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 06/01/2016] [Indexed: 11/15/2022] Open
Abstract
In view of the European Union regulations 1107/2009 and 528/2012, which say that basic substances in plant protection and biocidal products marketed in the European Union (EU) should not have an inherent capacity to cause endocrine disruption, an initiative was started to define scientific criteria for the identification of endocrine disruptors (EDs). The objectives of the EU strategy on EDs are to protect human health and the environment, to assure the functioning of the market, and to provide clear and coherent criteria for the identification of EDs that could have broad application in the EU legislation. Policy issues were to be addressed by the Ad-hoc group of Commission Services, EU Agencies and Member States established in 2010, whereas the scientific issues were to be addressed by the Endocrine Disruptors Expert Advisory Group (ED EAG), established in 2011. The ED EAG adopted the 2002 World Health Organization (WHO) definition of endocrine disruptor and agreed that for its identification it is necessary to produce convincing evidence of a biologically plausible causal link between an adverse effect and endocrine disrupting mode of action. In 2014, the European Commission proposed four ED identification criteria options and three regulatory options, which are now being assessed for socio-economic, environmental, and health impact. Slovenia supports the establishing of identification criteria and favours option 4, according to which ED identification should be based on the WHO definition with the addition of potency as an element of hazard characterisation. As for regulatory options, Slovenia favours the risk-based rather than hazard-based regulation.
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Bogen KT. Linear-No-Threshold Default Assumptions for Noncancer and Nongenotoxic Cancer Risks: A Mathematical and Biological Critique. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2016; 36:589-604. [PMID: 26249816 DOI: 10.1111/risa.12460] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
To improve U.S. Environmental Protection Agency (EPA) dose-response (DR) assessments for noncarcinogens and for nonlinear mode of action (MOA) carcinogens, the 2009 NRC Science and Decisions Panel recommended that the adjustment-factor approach traditionally applied to these endpoints should be replaced by a new default assumption that both endpoints have linear-no-threshold (LNT) population-wide DR relationships. The panel claimed this new approach is warranted because population DR is LNT when any new dose adds to a background dose that explains background levels of risk, and/or when there is substantial interindividual heterogeneity in susceptibility in the exposed human population. Mathematically, however, the first claim is either false or effectively meaningless and the second claim is false. Any dose-and population-response relationship that is statistically consistent with an LNT relationship may instead be an additive mixture of just two quasi-threshold DR relationships, which jointly exhibit low-dose S-shaped, quasi-threshold nonlinearity just below the lower end of the observed "linear" dose range. In this case, LNT extrapolation would necessarily overestimate increased risk by increasingly large relative magnitudes at diminishing values of above-background dose. The fact that chemically-induced apoptotic cell death occurs by unambiguously nonlinear, quasi-threshold DR mechanisms is apparent from recent data concerning this quintessential toxicity endpoint. The 2009 NRC Science and Decisions Panel claims and recommendations that default LNT assumptions be applied to DR assessment for noncarcinogens and nonlinear MOA carcinogens are therefore not justified either mathematically or biologically.
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Dong Z, Liu Y, Duan L, Bekele D, Naidu R. Uncertainties in human health risk assessment of environmental contaminants: A review and perspective. ENVIRONMENT INTERNATIONAL 2015; 85:120-32. [PMID: 26386465 DOI: 10.1016/j.envint.2015.09.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 08/31/2015] [Accepted: 09/02/2015] [Indexed: 05/24/2023]
Abstract
Addressing uncertainties in human health risk assessment is a critical issue when evaluating the effects of contaminants on public health. A range of uncertainties exist through the source-to-outcome continuum, including exposure assessment, hazard and risk characterisation. While various strategies have been applied to characterising uncertainty, classical approaches largely rely on how to maximise the available resources. Expert judgement, defaults and tools for characterising quantitative uncertainty attempt to fill the gap between data and regulation requirements. The experiences of researching 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) illustrated uncertainty sources and how to maximise available information to determine uncertainties, and thereby provide an 'adequate' protection to contaminant exposure. As regulatory requirements and recurring issues increase, the assessment of complex scenarios involving a large number of chemicals requires more sophisticated tools. Recent advances in exposure and toxicology science provide a large data set for environmental contaminants and public health. In particular, biomonitoring information, in vitro data streams and computational toxicology are the crucial factors in the NexGen risk assessment, as well as uncertainties minimisation. Although in this review we cannot yet predict how the exposure science and modern toxicology will develop in the long-term, current techniques from emerging science can be integrated to improve decision-making.
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Affiliation(s)
- Zhaomin Dong
- The Faculty of Science and Information Technology, University of Newcastle, University Drive, Callaghan, NSW 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, Mawson Lakes, SA 5095, Australia
| | - Yanju Liu
- The Faculty of Science and Information Technology, University of Newcastle, University Drive, Callaghan, NSW 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, Mawson Lakes, SA 5095, Australia
| | - Luchun Duan
- The Faculty of Science and Information Technology, University of Newcastle, University Drive, Callaghan, NSW 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, Mawson Lakes, SA 5095, Australia
| | - Dawit Bekele
- The Faculty of Science and Information Technology, University of Newcastle, University Drive, Callaghan, NSW 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, Mawson Lakes, SA 5095, Australia
| | - Ravi Naidu
- The Faculty of Science and Information Technology, University of Newcastle, University Drive, Callaghan, NSW 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, Mawson Lakes, SA 5095, Australia.
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Chiu WA, Slob W. A Unified Probabilistic Framework for Dose-Response Assessment of Human Health Effects. ENVIRONMENTAL HEALTH PERSPECTIVES 2015; 123:1241-54. [PMID: 26006063 PMCID: PMC4671238 DOI: 10.1289/ehp.1409385] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 05/19/2015] [Indexed: 05/19/2023]
Abstract
BACKGROUND When chemical health hazards have been identified, probabilistic dose-response assessment ("hazard characterization") quantifies uncertainty and/or variability in toxicity as a function of human exposure. Existing probabilistic approaches differ for different types of endpoints or modes-of-action, lacking a unifying framework. OBJECTIVES We developed a unified framework for probabilistic dose-response assessment. METHODS We established a framework based on four principles: a) individual and population dose responses are distinct; b) dose-response relationships for all (including quantal) endpoints can be recast as relating to an underlying continuous measure of response at the individual level; c) for effects relevant to humans, "effect metrics" can be specified to define "toxicologically equivalent" sizes for this underlying individual response; and d) dose-response assessment requires making adjustments and accounting for uncertainty and variability. We then derived a step-by-step probabilistic approach for dose-response assessment of animal toxicology data similar to how nonprobabilistic reference doses are derived, illustrating the approach with example non-cancer and cancer datasets. RESULTS Probabilistically derived exposure limits are based on estimating a "target human dose" (HDMI), which requires risk management-informed choices for the magnitude (M) of individual effect being protected against, the remaining incidence (I) of individuals with effects ≥ M in the population, and the percent confidence. In the example datasets, probabilistically derived 90% confidence intervals for HDMI values span a 40- to 60-fold range, where I = 1% of the population experiences ≥ M = 1%-10% effect sizes. CONCLUSIONS Although some implementation challenges remain, this unified probabilistic framework can provide substantially more complete and transparent characterization of chemical hazards and support better-informed risk management decisions.
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Affiliation(s)
- Weihsueh A Chiu
- National Center for Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Washington, DC, USA
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24
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Haney J. Implications of dose-dependent target tissue absorption for linear and non-linear/threshold approaches in development of a cancer-based oral toxicity factor for hexavalent chromium. Regul Toxicol Pharmacol 2015; 72:194-201. [DOI: 10.1016/j.yrtph.2015.04.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 04/09/2015] [Accepted: 04/15/2015] [Indexed: 10/23/2022]
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Futran Fuhrman V, Tal A, Arnon S. Why endocrine disrupting chemicals (EDCs) challenge traditional risk assessment and how to respond. JOURNAL OF HAZARDOUS MATERIALS 2015; 286:589-611. [PMID: 25646754 DOI: 10.1016/j.jhazmat.2014.12.012] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 12/02/2014] [Accepted: 12/08/2014] [Indexed: 05/11/2023]
Abstract
Endocrine disrupting compounds (EDCs) are a diverse group of "chemicals of emerging concern" which have attracted much interest from the research community since the 1990s. Today there is still no definitive risk assessment tool for EDCs. While some decision making organizations have attempted to design methodology guidelines to evaluate the potential risk from this broadly defined group of constituents, risk assessors still face many uncertainties and unknowns. Until a risk assessment paradigm is designed specifically for EDCs and is vetted by the field, traditional risk assessment tools may be used with caution to evaluate EDCs. In doing so, each issue of contention should be addressed with transparency in order to leverage available information and technology without sacrificing integrity or accuracy. The challenges that EDCs pose to traditional risk assessment are described in this article to assist in this process.
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Affiliation(s)
- Vivian Futran Fuhrman
- Institute for Dryland, Environmental and Desert Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer 84990, Israel.
| | - Alon Tal
- Institute for Dryland, Environmental and Desert Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer 84990, Israel.
| | - Shai Arnon
- Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer 84990, Israel.
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Mechanisms of action for arsenic in cardiovascular toxicity and implications for risk assessment. Toxicology 2015; 331:78-99. [PMID: 25771173 DOI: 10.1016/j.tox.2015.02.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Revised: 02/09/2015] [Accepted: 02/27/2015] [Indexed: 11/20/2022]
Abstract
The possibility of an association between inorganic arsenic (iAs) exposure and cardiovascular outcomes has received increasing attention in the literature over the past decade. The United States Environmental Protection Agency (US EPA) is currently revising its Integrated Risk Assessment System (IRIS) review of iAs, and one of the non-cancer endpoints of interest is cardiovascular disease (CVD). Despite the increased interest in this area, substantial gaps remain in the available information, particularly regarding the mechanism of action (MOA) by which iAs could cause or exacerbate CVD. Few studies specifically address the plausibility of an association between iAs and CVD at the low exposure levels which are typical in the United States (i.e., below 100 μg As/L in drinking water). We have conducted a review and evaluation of the animal, mechanistic, and human data relevant to the potential MOAs of iAs and CVD. Specifically, we evaluated the most common proposed MOAs, which include disturbance of endothelial function and hepatic dysfunction. Our analysis of the available evidence indicates that there is not a well-established MOA for iAs in the development or progression of CVD. Few human studies of the potential MOAs have addressed plausibility at low doses and the applicability of extrapolation from animal studies to humans is questionable. However, the available evidence indicates that regardless of the specific MOA, the effects of iAs on physiological processes at the cellular level appear to operate via a threshold mechanism. This finding is consistent with the lack of association of CVD with iAs exposure in humans at levels below 100 μg/L, particularly when considering important exposure and risk modifiers such as nutrition and genetics. Based on this analysis, we conclude that there are no data supporting a linear dose-response relationship between iAs and CVD, indicating this relationship has a threshold.
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DeBord DG, Burgoon L, Edwards SW, Haber LT, Kanitz MH, Kuempel E, Thomas RS, Yucesoy B. Systems Biology and Biomarkers of Early Effects for Occupational Exposure Limit Setting. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2015; 12 Suppl 1:S41-54. [PMID: 26132979 PMCID: PMC4654673 DOI: 10.1080/15459624.2015.1060324] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
In a recent National Research Council document, new strategies for risk assessment were described to enable more accurate and quicker assessments. This report suggested that evaluating individual responses through increased use of bio-monitoring could improve dose-response estimations. Identification of specific biomarkers may be useful for diagnostics or risk prediction as they have the potential to improve exposure assessments. This paper discusses systems biology, biomarkers of effect, and computational toxicology approaches and their relevance to the occupational exposure limit setting process. The systems biology approach evaluates the integration of biological processes and how disruption of these processes by chemicals or other hazards affects disease outcomes. This type of approach could provide information used in delineating the mode of action of the response or toxicity, and may be useful to define the low adverse and no adverse effect levels. Biomarkers of effect are changes measured in biological systems and are considered to be preclinical in nature. Advances in computational methods and experimental -omics methods that allow the simultaneous measurement of families of macromolecules such as DNA, RNA, and proteins in a single analysis have made these systems approaches feasible for broad application. The utility of the information for risk assessments from -omics approaches has shown promise and can provide information on mode of action and dose-response relationships. As these techniques evolve, estimation of internal dose and response biomarkers will be a critical test of these new technologies for application in risk assessment strategies. While proof of concept studies have been conducted that provide evidence of their value, challenges with standardization and harmonization still need to be overcome before these methods are used routinely.
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Affiliation(s)
- D. Gayle DeBord
- National Institute for Occupational Safety and Health, Division of Applied Research and Technology, Cincinnati, Ohio
| | - Lyle Burgoon
- U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, North Carolina
| | - Stephen W. Edwards
- U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, North Carolina
| | - Lynne T. Haber
- Toxicology Excellence for Risk Assessment (TERA), Cincinnati, Ohio
| | - M. Helen Kanitz
- National Institute for Occupational Safety and Health, Division of Applied Research and Technology, Cincinnati, Ohio
| | - Eileen Kuempel
- National Institute for Occupational Safety and Health, Education and Information Division, Cincinnati, Ohio
| | - Russell S. Thomas
- U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, North Carolina
- The Hamner Institute for Health Sciences, Research Triangle Park, North Carolina
| | - Berran Yucesoy
- National Institute for Occupational Safety and Health, Heath Effects Laboratory Division, Morgantown, West Virginia
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Zhang Q, Bhattacharya S, Conolly RB, Clewell HJ, Kaminski NE, Andersen ME. Molecular signaling network motifs provide a mechanistic basis for cellular threshold responses. ENVIRONMENTAL HEALTH PERSPECTIVES 2014; 122:1261-70. [PMID: 25117432 PMCID: PMC4256703 DOI: 10.1289/ehp.1408244] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Accepted: 08/12/2014] [Indexed: 05/02/2023]
Abstract
BACKGROUND Increasingly, there is a move toward using in vitro toxicity testing to assess human health risk due to chemical exposure. As with in vivo toxicity testing, an important question for in vitro results is whether there are thresholds for adverse cellular responses. Empirical evaluations may show consistency with thresholds, but the main evidence has to come from mechanistic considerations. OBJECTIVES Cellular response behaviors depend on the molecular pathway and circuitry in the cell and the manner in which chemicals perturb these circuits. Understanding circuit structures that are inherently capable of resisting small perturbations and producing threshold responses is an important step towards mechanistically interpreting in vitro testing data. METHODS Here we have examined dose-response characteristics for several biochemical network motifs. These network motifs are basic building blocks of molecular circuits underpinning a variety of cellular functions, including adaptation, homeostasis, proliferation, differentiation, and apoptosis. For each motif, we present biological examples and models to illustrate how thresholds arise from specific network structures. DISCUSSION AND CONCLUSION Integral feedback, feedforward, and transcritical bifurcation motifs can generate thresholds. Other motifs (e.g., proportional feedback and ultrasensitivity)produce responses where the slope in the low-dose region is small and stays close to the baseline. Feedforward control may lead to nonmonotonic or hormetic responses. We conclude that network motifs provide a basis for understanding thresholds for cellular responses. Computational pathway modeling of these motifs and their combinations occurring in molecular signaling networks will be a key element in new risk assessment approaches based on in vitro cellular assays.
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Affiliation(s)
- Qiang Zhang
- Institute for Chemical Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina, USA
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Susceptibility Based Upon Chemical Interaction with Disease Processes: Potential Implications for Risk Assessment. Curr Environ Health Rep 2014. [DOI: 10.1007/s40572-014-0030-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Gore AC, Balthazart J, Bikle D, Carpenter DO, Crews D, Czernichow P, Diamanti-Kandarakis E, Dores RM, Grattan D, Hof PR, Hollenberg AN, Lange C, Lee AV, Levine JE, Millar RP, Nelson RJ, Porta M, Poth M, Power DM, Prins GS, Ridgway EC, Rissman EF, Romijn JA, Sawchenko PE, Sly PD, Söder O, Taylor HS, Tena-Sempere M, Vaudry H, Wallen K, Wang Z, Wartofsky L, Watson CS. Policy decisions on endocrine disruptors should be based on science across disciplines: a response to Dietrich et al. Horm Res Paediatr 2014; 80:305-8. [PMID: 24107550 DOI: 10.1159/000355668] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- A C Gore
- Division of Pharmacology and Toxicology, The University of Texas, Austin, Tex., USA
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The impact of recent advances in research on arsenic cancer risk assessment. Regul Toxicol Pharmacol 2014; 69:91-104. [DOI: 10.1016/j.yrtph.2014.02.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 02/05/2014] [Accepted: 02/07/2014] [Indexed: 11/23/2022]
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Oo C, Duchin KL. Can CYP3A Activity Be Evaluated for Drug Interaction Using a Nanogram Dose of Probe Drug? Clin Pharmacol Ther 2014; 95:489. [DOI: 10.1038/clpt.2014.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 12/30/2013] [Indexed: 11/10/2022]
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Gore AC, Balthazart J, Bikle D, Carpenter DO, Crews D, Czernichow P, Diamanti-Kandarakis E, Dores RM, Grattan D, Hof PR, Hollenberg AN, Lange C, Lee AV, Levine JE, Millar RP, Nelson RJ, Porta M, Poth M, Power DM, Prins GS, Ridgway EC, Rissman EF, Romijn JA, Sawchenko PE, Sly PD, Söder O, Taylor HS, Tena-Sempere M, Vaudry H, Wallen K, Wang Z, Wartofsky L, Watson CS. Reprint of: policy decisions on endocrine disruptors should be based on science across disciplines: a response to Dietrich et al. Horm Behav 2014; 65:190-3. [PMID: 24289987 DOI: 10.1016/j.yhbeh.2013.09.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- A C Gore
- Division of Pharmacology and Toxicology, The University of Texas, Austin, TX 78712, USA.
| | - J Balthazart
- University of Liège, GIGA Neurosciences, B-4000 Liège, Belgium
| | - D Bikle
- VA Medical Center, University of California, San Francisco, San Francisco, CA 94143, USA
| | - D O Carpenter
- Institute for Health and the Environment, University at Albany, State University of New York, Albany, NY 12222, USA
| | - D Crews
- Section of Integrative Biology, The University of Texas, Austin, TX 78712, USA
| | | | | | - R M Dores
- Department of Biological Sciences, University of Denver, Denver, CO 80208, USA
| | - D Grattan
- Department of Anatomy, University of Otago, North Dunedin 9016, New Zealand
| | - P R Hof
- Icahn School of Medicine at Mt Sinai, New York, NY 10029, USA
| | - A N Hollenberg
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA
| | - C Lange
- University of Minnesota Masonic Cancer Center, Minneapolis, MN 55455, USA
| | - A V Lee
- University of Pittsburgh Cancer Institute, Magee Women's Research Institute, Pittsburgh, PA 15213, USA
| | - J E Levine
- Wisconsin National Primate Research Center, Madison, WI 53715, USA
| | - R P Millar
- UCT/MRC Receptor Biology Unit, University of Cape Town, Cape Town, South Africa
| | - R J Nelson
- Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - M Porta
- Hospital del Mar Institute of Medical Research, School of Medicine, Universitat Autònoma de Barcelona, 080041 Barcelona, Spain
| | - M Poth
- Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - D M Power
- Department of Biosciences, Universidade do Algarve, 8005-139 Faro, Portugal
| | - G S Prins
- Department of Physiology and Biophysics, University of Illinois, Chicago, IL 60612, USA
| | - E C Ridgway
- Department of Medicine, University of Colorado School of Medicine, Denver, CO 80208, USA
| | - E F Rissman
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA
| | - J A Romijn
- Division of Medicine, Academic Medical Center, University of Amsterdam, 1012 WX Amsterdam, The Netherlands
| | - P E Sawchenko
- Laboratory of Neuronal Structure and Function, The Salk Institute, La Jolla, CA 92037, USA
| | - P D Sly
- Queensland Children's Medical Institute, University of Queensland, Royal Children's Hospital, Brisbane, Queensland 4000, Australia
| | - O Söder
- Karolinska Institutet at Karolinska University Hospital Solna, 171 76 Stockholm, Sweden
| | - H S Taylor
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale School of Medicine, New Haven, CT 06510, USA
| | - M Tena-Sempere
- Department of Cell Biology and Physiology, University of Córdoba, 14071 Córdoba, Spain
| | - H Vaudry
- Institut National de la Santé et de la Recherche Médicale U982, University of Rouen, 76821 Rouen, France
| | - K Wallen
- Department of Psychology, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30322, USA
| | - Z Wang
- Department of Psychology and Neuroscience, Florida State University, Tallahassee, FL 32306, USA
| | - L Wartofsky
- Department of Medicine, Washington Hospital Center, Washington, DC 20010, USA
| | - C S Watson
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
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Gore AC, Balthazart J, Bikle D, Carpenter DO, Crews D, Czernichow P, Diamanti-Kandarakis E, Dores RM, Grattan D, Hof PR, Hollenberg AN, Lange C, Lee AV, Levine JE, Millar RP, Nelson RJ, Porta M, Poth M, Power DM, Prins GS, Ridgway EC, Rissman EF, Romijn JA, Sawchenko PE, Sly PD, Söder O, Taylor HS, Tena-Sempere M, Vaudry H, Wallen K, Wang Z, Wartofsky L, Watson CS. Reprint of: policy decisions on endocrine disruptors should be based on science across disciplines: a response to Dietrich, et al. Front Neuroendocrinol 2014; 35:2-5. [PMID: 24268499 DOI: 10.1016/j.yfrne.2013.09.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 09/17/2013] [Indexed: 11/24/2022]
Affiliation(s)
- A C Gore
- Pharmacology and Toxicology, The University of Texas at Austin, Austin, TX 78712, United States.
| | - J Balthazart
- University of Liège, GIGA Neurosciences, B-4000 Liège, Belgium
| | - D Bikle
- VA Medical Center and University of California, San Francisco, San Francisco, CA 94143, United States
| | - D O Carpenter
- Institute for Health and the Environment, University at Albany, State University of New York, Albany, NY 12222, United States
| | - D Crews
- Section of Integrative Biology, The University of Texas, Austin, TX 78712, United States
| | - P Czernichow
- Professor Emeritus of Pediatrics, University of Paris, 75006 Paris, France
| | | | - R M Dores
- Department of Biological Sciences, University of Denver, Denver, CO 80208, United States
| | - D Grattan
- Department of Anatomy, University of Otago, North Dunedin 9016, New Zealand
| | - P R Hof
- Icahn School of Medicine at Mt Sinai, New York, NY 10029, United States
| | | | - C Lange
- University of Minnesota Masonic Cancer Center, Minneapolis, MN 55455, United States
| | - A V Lee
- University of Pittsburgh Cancer Institute and Magee Women's Research Institute, Pittsburgh, PA 15213, United States
| | - J E Levine
- Wisconsin National Primate Research Center, Madison, WI 53715, United States
| | - R P Millar
- UCT/MRC Receptor Biology Unit, University of Cape Town, Cape Town, South Africa
| | - R J Nelson
- Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, OH 43210, United States
| | - M Porta
- Hospital del Mar Institute of Medical Research and School of Medicine, Universitat Autònoma de Barcelona, 080041 Barcelona, Spain
| | - M Poth
- Uniformed Services University of the Health Sciences, Bethesda, MD 20814, United States
| | - D M Power
- Department of Biosciences, Universidade do Algarve, 8005-139 Faro, Portugal
| | - G S Prins
- Department of Physiology and Biophysics, University of Illinois, Chicago, IL 60612, United States
| | - E C Ridgway
- Department of Medicine, University of Colorado School of Medicine, Denver, CO 80208, United States
| | - E F Rissman
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Virginia, Charlottesville, VA 22908, United States
| | - J A Romijn
- Division of Medicine, Academic Medical Center, University of Amsterdam, 1012 WX Amsterdam, The Netherlands
| | - P E Sawchenko
- Laboratory of Neuronal Structure and Function, The Salk Institute, La Jolla, CA 92037, United States
| | - P D Sly
- Queensland Children's Medical Institute, University of Queensland, Royal Children's Hospital, Brisbane, Queensland 4000, Australia
| | - O Söder
- Karolinska Institutet at Karolinska University Hospital Solna, 171 76 Stockholm, Sweden
| | - H S Taylor
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale School of Medicine, New Haven, CT 06510, United States
| | - M Tena-Sempere
- Department of Cell Biology and Physiology, University of Córdoba, 14071 Córdoba, Spain
| | - H Vaudry
- Institut National de la Santé et de la Recherche Médicale U982, University of Rouen, 76821 Rouen, France
| | - K Wallen
- Department of Psychology and Yerkes National Primate Research Center, Emory University, Atlanta, GA 30322, United States
| | - Z Wang
- Department of Psychology and Neuroscience, Florida State University, Tallahassee, FL 32306, United States
| | - L Wartofsky
- Department of Medicine, Washington Hospital Center, Washington, DC 20010, United States
| | - C S Watson
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, United States
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35
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Gore AC, Balthazart J, Bikle D, Carpenter DO, Crews D, Czernichow P, Diamanti-Kandarakis E, Dores RM, Grattan D, Hof PR, Hollenberg AN, Lange C, Lee AV, Levine JE, Millar RP, Nelson RJ, Porta M, Poth M, Power DM, Prins GS, Ridgway EC, Rissman EF, Romijn JA, Sawchenko PE, Sly PD, Söder O, Taylor HS, Tena-Sempere M, Vaudry H, Wallen K, Wang Z, Wartofsky L, Watson CS. Policy decisions on endocrine disruptors should be based on science across disciplines: a response to Dietrich et al. Eur J Endocrinol 2013; 169:E1-4. [PMID: 24057478 DOI: 10.1530/eje-13-0763] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- A C Gore
- Division of Pharmacology and Toxicology, The University of Texas, Austin, Texas 78712, USA
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Scientifically unfounded precaution drives European Commission's recommendations on EDC regulation, while defying common sense, well-established science and risk assessment principles. Toxicon 2013; 76:A1-A2. [DOI: 10.1016/j.toxicon.2013.10.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Budinsky RA, Schrenk D, Simon T, Van den Berg M, Reichard JF, Silkworth JB, Aylward LL, Brix A, Gasiewicz T, Kaminski N, Perdew G, Starr TB, Walker NJ, Rowlands JC. Mode of action and dose–response framework analysis for receptor-mediated toxicity: The aryl hydrocarbon receptor as a case study. Crit Rev Toxicol 2013; 44:83-119. [DOI: 10.3109/10408444.2013.835787] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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39
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Gore AC, Balthazart J, Bikle D, Carpenter DO, Crews D, Czernichow P, Diamanti-Kandarakis E, Dores RM, Grattan D, Hof PR, Hollenberg AN, Lange C, Lee AV, Levine JE, Millar RP, Nelson RJ, Porta M, Poth M, Power DM, Prins GS, Ridgway EC, Rissman EF, Romijn JA, Sawchenko PE, Sly PD, Söder O, Taylor HS, Tena-Sempere M, Vaudry H, Wallen K, Wang Z, Wartofsky L, Watson CS. Policy decisions on endocrine disruptors should be based on science across disciplines: a response to Dietrich et al. Endocrinology 2013; 154:3957-60. [PMID: 24048095 PMCID: PMC5398595 DOI: 10.1210/en.2013-1854] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- A C Gore
- PhD, Editor-in-Chief, Endocrinology, Gustavus, Louise Pfeiffer Professor of Pharmacology, Toxicology, The University of Texas at Austin, Austin, Texas 78712.
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40
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Gore AC, Balthazart J, Bikle D, Carpenter DO, Crews D, Czernichow P, Diamanti-Kandarakis E, Dores RM, Grattan D, Hof PR, Hollenberg AN, Lange C, Lee AV, Levine JE, Millar RP, Nelson RJ, Porta M, Poth M, Power DM, Prins GS, Ridgway EC, Rissman EF, Romijn JA, Sawchenko PE, Sly PD, Söder O, Taylor HS, Tena-Sempere M, Vaudry H, Wallen K, Wang Z, Wartofsky L, Watson CS. Policy decisions on endocrine disruptors should be based on science across disciplines: a response to Dietrichet al. Andrology 2013; 1:802-5. [DOI: 10.1111/j.2047-2927.2013.00151.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- A. C. Gore
- Division of Pharmacology and Toxicology; The University of Texas; Austin TX USA
| | - J. Balthazart
- University of Liège; GIGA Neurosciences; Liège Belgium
| | - D. Bikle
- VA Medical Center and University of California, San Francisco; San Francisco CA USA
| | - D. O. Carpenter
- Institute for Health and the Environment; University at Albany; State University of New York; Albany NY USA
| | - D. Crews
- Section of Integrative Biology; The University of Texas; Austin TX USA
| | | | | | - R. M. Dores
- Department of Biological Sciences; University of Denver; Denver CO USA
| | - D. Grattan
- Department of Anatomy; University of Otago; North Dunedin New Zealand
| | - P. R. Hof
- Icahn School of Medicine at Mt Sinai; New York NY USA
| | - A. N. Hollenberg
- Beth Israel Deaconess Medical Center; Harvard Medical School; Boston MA USA
| | - C. Lange
- University of Minnesota Masonic Cancer Center; Minneapolis MN USA
| | - A. V. Lee
- University of Pittsburgh Cancer Institute and Magee Women's Research Institute; Pittsburgh PA USA
| | - J. E. Levine
- Wisconsin National Primate Research Center; Madison WI USA
| | - R. P. Millar
- UCT/MRC Receptor Biology Unit; University of Cape Town; Cape Town South Africa
| | - R. J. Nelson
- Department of Neuroscience; The Ohio State University Wexner Medical Center; Columbus OH USA
| | - M. Porta
- Hospital del Mar Institute of Medical Research and School of Medicine; Universitat Autònoma de Barcelona; Barcelona Spain
| | - M. Poth
- Uniformed Services University of the Health Sciences; Bethesda MD USA
| | - D. M. Power
- Department of Biosciences; Universidade do Algarve; Faro Portugal
| | - G. S. Prins
- Department of Physiology and Biophysics; University of Illinois; Chicago IL USA
| | - E. C. Ridgway
- Department of Medicine; University of Colorado School of Medicine; Denver CO USA
| | - E. F. Rissman
- Department of Biochemistry and Molecular Genetics; School of Medicine; University of Virginia; Charlottesville VA USA
| | - J. A. Romijn
- Division of Medicine; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
| | - P. E. Sawchenko
- Laboratory of Neuronal Structure and Function; The Salk Institute; La Jolla CA USA
| | - P. D. Sly
- Queensland Children's Medical Institute; University of Queensland; Royal Children's Hospital; Brisbane Qld Australia
| | - O. Söder
- Karolinska Institutet at Karolinska University Hospital Solna; Stockholm Sweden
| | - H. S. Taylor
- Department of Obstetrics, Gynecology and Reproductive Sciences; Yale School of Medicine; New Haven CT USA
| | - M. Tena-Sempere
- Department of Cell Biology and Physiology; University of Córdoba; Córdoba Spain
| | - H. Vaudry
- Institut National de la Santé et de la Recherche Médicale U982; University of Rouen; Rouen France
| | - K. Wallen
- Department of Psychology and Yerkes National Primate Research Center; Emory University; Atlanta GA USA
| | - Z. Wang
- Department of Psychology and Neuroscience; Florida State University; Tallahassee FL USA
| | - L. Wartofsky
- Department of Medicine; Washington Hospital Center; Washington DC USA
| | - C. S. Watson
- Department of Biochemistry and Molecular Biology; University of Texas Medical Branch; Galveston TX USA
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Andersen ME, Preston RJ, Maier A, Willis AM, Patterson J. Dose–response approaches for nuclear receptor-mediated modes of action for liver carcinogenicity: Results of a workshop. Crit Rev Toxicol 2013; 44:50-63. [DOI: 10.3109/10408444.2013.835785] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Dietrich D, von Aulock S, Marquardt HWJ, Blaauboer BJ, Dekant W, Kehrer J, Hengstler JG, Collier AC, Gori GB, Pelkonen O, Lang F, Nijkamp FP, Stemmer K, Li A, Savolainen K, Hayes AW, Gooderham N, Harvey A. Open letter to the European Commission: scientifically unfounded precaution drives European Commission's recommendations on EDC regulation, while defying common sense, well-established science, and risk assessment principles. Arch Toxicol 2013; 87:1739-41. [PMID: 23979651 DOI: 10.1007/s00204-013-1117-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 08/06/2013] [Indexed: 11/25/2022]
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Dietrich DR, von Aulock S, Marquardt H, Blaauboer B, Dekant W, Kehrer J, Hengstler J, Collier A, Gori GB, Pelkonen OP, Lang F, Nijkamp FP, Stemmer K, Li A, Savolainen K, Hayes AW, Gooderham N, Harvey A. Scientifically unfounded precaution drives European Commission's recommendations on EDC regulation, while defying common sense, well-established science and risk assessment principles. Toxicol In Vitro 2013; 27:2110-4. [PMID: 23850741 DOI: 10.1016/j.tiv.2013.07.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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44
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Dietrich DR, von Aulock S, Marquardt H, Blaauboer B, Dekant W, Kehrer J, Hengstler J, Collier A, Gori GB, Pelkonen O, Lang F, Nijkamp FP, Stemmer K, Li A, Savolainen K, Hayes AW, Gooderham N, Harvey A. Scientifically unfounded precaution drives European Commission's recommendations on EDC regulation, while defying common sense, well-established science and risk assessment principles. Food Chem Toxicol 2013; 62:A1-4. [PMID: 23835284 DOI: 10.1016/j.fct.2013.07.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Dietrich DR, Aulock SV, Marquardt H, Blaauboer B, Dekant W, Kehrer J, Hengstler J, Collier A, Gori GB, Pelkonen O, Lang F, Barile FA, Nijkamp FP, Stemmer K, Li A, Savolainen K, Hayes AW, Gooderham N, Harvey A. Scientifically unfounded precaution drives European Commission's recommendations on EDC regulation, while defying common sense, well-established science and risk assessment principles. Chem Biol Interact 2013; 205:A1-5. [PMID: 23832050 DOI: 10.1016/j.cbi.2013.07.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Dourson M, Becker RA, Haber LT, Pottenger LH, Bredfeldt T, Fenner-Crisp PA. Advancing human health risk assessment: integrating recent advisory committee recommendations. Crit Rev Toxicol 2013; 43:467-92. [PMID: 23844697 PMCID: PMC3725687 DOI: 10.3109/10408444.2013.807223] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Revised: 05/16/2013] [Accepted: 05/17/2013] [Indexed: 11/13/2022]
Abstract
Over the last dozen years, many national and international expert groups have considered specific improvements to risk assessment. Many of their stated recommendations are mutually supportive, but others appear conflicting, at least in an initial assessment. This review identifies areas of consensus and difference and recommends a practical, biology-centric course forward, which includes: (1) incorporating a clear problem formulation at the outset of the assessment with a level of complexity that is appropriate for informing the relevant risk management decision; (2) using toxicokinetics and toxicodynamic information to develop Chemical Specific Adjustment Factors (CSAF); (3) using mode of action (MOA) information and an understanding of the relevant biology as the key, central organizing principle for the risk assessment; (4) integrating MOA information into dose-response assessments using existing guidelines for non-cancer and cancer assessments; (5) using a tiered, iterative approach developed by the World Health Organization/International Programme on Chemical Safety (WHO/IPCS) as a scientifically robust, fit-for-purpose approach for risk assessment of combined exposures (chemical mixtures); and (6) applying all of this knowledge to enable interpretation of human biomonitoring data in a risk context. While scientifically based defaults will remain important and useful when data on CSAF or MOA to refine an assessment are absent or insufficient, assessments should always strive to use these data. The use of available 21st century knowledge of biological processes, clinical findings, chemical interactions, and dose-response at the molecular, cellular, organ and organism levels will minimize the need for extrapolation and reliance on default approaches.
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Affiliation(s)
- Michael Dourson
- Toxicology Excellence for Risk Assessment, Cincinnati, OH, USA.
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47
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Henry H. EPA's Stage 2 Disinfection Byproducts Rules (DBPR) and Northern Kentucky Water: An Economic and Scientific Review. Dose Response 2013; 11:517-42. [PMID: 24298228 PMCID: PMC3834744 DOI: 10.2203/dose-response.12-056.henry] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Implementation of EPA's Stage 2 Disinfection Byproducts Rules (DBPR) in Northern Kentucky will cause a water rate increase of over 25%. Hence a review was undertaken, considering both economics and science in the context of President Obama's 2009 scientific integrity directive. The rules purport to avoid up to 0.49% of new bladder cancers by reducing the levels of DBPs in drinking water - a benefit so small that failure to implement will not cause unreasonable risk to health (URTH). It suggests at most one Northern Kentucky death avoided over 17 years for a cost of $136,000,000 ($1700 per household). Even this small benefit is probably overstated. EPA finds no "causal link" between DBPs and bladder cancer, and EPA acknowledges problems with the epidemiological data used in their calculation: the data appear contradictory and inconsistent, may be skewed toward "positive" results, and suggest different cancer sites than animal studies. Two similar international agencies disagree with EPA's conclusions. The science is based on the Linear No Threshold (LNT) dose response model for DBPs, but this may not be the correct model. 83% of EPA's epidemiological data show a statistical possibility that low levels of DBPs might be beneficial or have no effect.
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Affiliation(s)
- Hugh Henry
- Department of Physics, Northern Kentucky University
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48
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Scientifically unfounded precaution drives European Commission's recommendations on EDC regulation, while defying common sense, well-established science and risk assessment principles. Toxicol Res (Camb) 2013. [DOI: 10.1039/c3tx90013d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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49
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Development of a cancer-based chronic inhalation reference value for hexavalent chromium based on a nonlinear-threshold carcinogenic assessment. Regul Toxicol Pharmacol 2012; 64:466-80. [DOI: 10.1016/j.yrtph.2012.10.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Revised: 10/15/2012] [Accepted: 10/16/2012] [Indexed: 12/29/2022]
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50
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Quantitative risk assessment methods for cancer and noncancer effects. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012. [PMID: 22974743 DOI: 10.1016/b978-0-12-415813-9.00009-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Human health risk assessments have evolved from the more qualitative approaches to more quantitative approaches in the past decade. This has been facilitated by the improvement in computer hardware and software capability and novel computational approaches being slowly recognized by regulatory agencies. These events have helped reduce the reliance on experimental animals as well as better utilization of published animal toxicology data in deriving quantitative toxicity indices that may be useful for risk management purposes. This chapter briefly describes some of the approaches as described in the guidance documents from several of the regulatory agencies as it pertains to hazard identification and dose-response assessment of a chemical. These approaches are contrasted with more novel computational approaches that provide a better grasp of the uncertainty often associated with chemical risk assessments.
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