Response to the Waalkes et al., Letter to the editor concerning our “letter to the editor, Re: Lung tumors in mice induced by “whole-life” inorganic arsenic exposure at human relevant doses, Waalkes et al., Arch Toxicol, 2014”

Cohen, Samuel M.; Arnold, Lora L.; Klaunig, James E.; Goodman, Jay I.

doi:10.1007/s00204-015-1614-6

Cited by 6 publications

(5 citation statements)

References 9 publications

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“…Our independent analysis of the Waalkes et al (2014) and Tokar et al (2011Tokar et al ( , 2012) data showed that low-dose inorganic arsenic exposures increase lung tumor incidences in CD1 male mice. Our conclusions were consistent with the findings of Waalkes et al (2014), which have subsequently been called into question by Cohen et al ( , 2015. In their Letter to the Editor, Cohen et al (2016) raised several concerns with our analysis, however none of their concerns were sufficient to refute the conclusion of our analysis of the Waalkes et al (2014) and Tokar et al (2011Tokar et al ( , 2012 data.…”

supporting

confidence: 86%

Response to Cohen et al. (2016) regarding response to Druwe and Burgoon

Druwe

Burgoon

2016

Arch Toxicol

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selection. The formulas and rationale we used were published along with the raw data needed to repeat the analysis as a JUPYTER notebook, which we referenced in the first letter and again above. A JUPYTER notebook is an web based notebook that contains both computer code (e.g., such as that run in R) and rich text elements such as figures, equations etc. A JUPYTER document are humans-readable documents that can also execute computer code simultaneously. In this way, we have made all of our analyses and the data completely transparent and accessible in our analysis report.Cohen et al.'s second concern expressed that we did not provide a rationale for the use of the Bernoulli distribution. The Bernoulli distribution is discussed in the statistical literature as the standard distribution when dealing with binary cases, such as success/failure, heads/tails, cancer/ no-cancer (Freedman et al. 2007;Kruske 2011). The case of the Waalkes and Tokar data is a classic binary case of tumor/no tumor, making the Bernoulli distribution the simplest distribution with the fewest number of parameters choices.Cohen et al.'s third concern expressed that our ROPE interval was arbitrary. We provided a rationale for the ROPE analysis in the report referenced in the previous letter and again above. We stated, "Expanding the ROPE slightly, such as to ±0.10, still would not bring the 95 % HDI within the ROPE. We do not believe that a ±10 % rope is justified, when dealing with tumor incidences in the control population that are approximately 28 %. Specifically, we do not believe it is biologically plausible that a tumor incidence that spans from 18 to 38 % can be considered practically equivalent, whereas one that spans from 23 to 33 % is."We also wanted to address Cohen et al.'s contention that the Haseman criteria should apply to a common tumor as

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supporting

confidence: 86%

Response to Cohen et al. (2016) regarding response to Druwe and Burgoon

Druwe

Burgoon

2016

Arch Toxicol

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“…From an experimental study, Waalkes et al reported that in utero i As exposure causes tumors in CD1 male mice. The conclusion of this study has been questioned by Cohen et al because of the relatively high incidence of spontaneous cancer in CD1 mice, poor survival of the low‐dose group, and lack of a dose‐response relationship. While a recent reevaluation by Druwe and Burgoon states that the original findings of Waalkes et al are supported, methodological limitations and other issues still remain and the interpretation of the Waalkes study is unclear …”

Section: Epidemiology Of Arsenic Toxicitymentioning

confidence: 67%

State of the science review of the health effects of inorganic arsenic: Perspectives for future research

Tchounwou

Yedjou

Udensi

et al. 2018

Environmental Toxicology

134

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Human exposure to inorganic arsenic (iAs) is a global health issue. Although there is strong evidence for iAs-induced toxicity at higher levels of exposure, many epidemiological studies evaluating its effects at low exposure levels have reported mixed results. We comprehensively reviewed the literature and evaluated the scientific knowledge on human exposure to arsenic, mechanisms of action, systemic and carcinogenic effects, risk characterization, and regulatory guidelines. We identified areas where additional research is needed. These priority areas include: (1) further development of animal models of iAs carcinogenicity to identify molecular events involved in iAs carcinogenicity; (2) characterization of underlying mechanisms of iAs toxicity; (3) assessment of genderspecific susceptibilities and other factors that modulate arsenic metabolism; (4) sufficiently powered epidemiological studies to ascertain relationship between iAs exposure and reproductive/ developmental effects; (5) evaluation of genetic/epigenetic determinants of iAs effects in children;and (6) epidemiological studies of people chronically exposed to low iAs concentrations.

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“…This makes biological sense and it is unfortunate that the analysis performed by Druwe and Burgoon (2016) ignores this key point. In addition, Druwe and Burgoon do not address any of the other issues raised by Cohen et al ( , 2015, in particular for a Bayesian statistical approach, the lack of historical data, not just the 3 studies most recently reported from the Waalkes group.…”

mentioning

confidence: 99%