Review of EPA's 2022 Draft Formaldehyde Assessment (2023) / Chapter Skim
Currently Skimming:
2 Methods and Organization
2 Methods and Organization
Pages 21-44
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 21... ...
Expert judgment is integral to the systematic review process, from question formulation, protocol development, study selection, and evaluation through determination of the strength of evidence of each evidence stream. It is particularly influential at the evidence integration step.
|
From page 22... ...
Process provides a framework for the IRIS process, showing where systematic review fits into the process and documenting the parallel, but separate, reviews for the three relevant evidence streams: human, animal, and mechanistic. The framework describes the flow of evidence utilization through the steps of evaluation of studies, evidence integration for hazard identification, and derivation of toxicity values.
|
From page 23... ...
The report assessed scientific, technical, and process changes made by EPA in response to the 2011 NRC recommendations. The 2014 NRC committee noted that EPA was making significant progress, and was incorporating systematic review principles as it implemented changes to the IRIS process.
|
From page 24... ...
The methods used in the 2022 Draft Assessment encompass eight steps that generally align with the processes described in the 2014 NRC report: evidence identification, evidence evaluation, evidence synthesis, and evidence integration to inform hazard identification and dose-response estimation. Finding: The 2022 Draft Assessment is responsive to the broad intent of the 2011 NRC review of EPA's 2010 Draft Assessment and the 2014 NRC review of the IRIS process.
|
From page 25... ...
The research questions inform the development of the assessment methods, which are typically documented in a protocol that is established before the assessment begins. The protocol provides comprehensive documentation of inclusion and exclusion criteria for compiling evidence, as well as the methods for the subsequent steps of the systematic review.
|
From page 26... ...
Specific methods for health outcome are described in the Main Assessment and the Appendices of the 2022 Draft Assessment. EPA notes that presenting "the assessment methods within the assessment documents rather than in a separate protocol is consistent with the practices within the IRIS Program at the time the formaldehyde assessment was being developed during 2012–2017" (EPA, 2023, p.
|
From page 27... ...
. Conclusion: Prepublished protocols are essential for future IRIS assessments to ensure transparency for systematic reviews in risk assessment.
|
From page 28... ...
The 2014 committee also recommended that contractors who perform the evidence identification for a systematic review adhere to the same standards and provide evidence of experience and expertise in the field. Approach to Evidence Identification in the 2022 Draft Assessment The steps EPA followed in conducting the literature search and the PECO assessment for inclusion and exclusion of studies are described in the Main Assessment as well as in the Appendices.
|
From page 29... ...
, the human and animal studies selected for inclusion are assessed for study quality, including risk of bias. FIGURE 2-4 Aspects of EPA's approach to study evaluation.
|
From page 30... ...
The domains included were related to study factors that influence internal validity, that is, whether the study is potentially affected by bias, which can lead to under- or overestimation of risk. The domains used for study evaluation are described in the Assessment Overview and the preface of the Main Assessment and in Appendix A
|
From page 31... ...
Animal studies are also evaluated in terms of domains that would influence internal validity or study sensitivity. Tables in Appendix A describe these domains, as does the text in the sections that precede the tables.
|
From page 32... ...
EVIDENCE SYNTHESIS (STEPS 5 AND 6) Evidence synthesis involves separately interpreting the results from human, animal, and mechanistic studies and reaching judgments as to the strength of evidence in each evidence stream.
|
From page 33... ...
Moreover, the committee emphasizes that all of the above-mentioned methods have undergone pilot testing, stakeholder vetting, and peer review and have been made public. Approach to Evidence Synthesis in the 2022 Draft Assessment EPA applies a set of considerations and a framework for assessing the strength of evidence in each of the evidence streams within an outcome class, which are described in the preface of the Main Assessment (p.
|
From page 34... ...
FIGURE 2-6 Aspects of EPA's approach relevant to evidence integration judgments. State of Practice The state of practice for evidence integration dates to landmark publications in the 1960s, including the 1964 report of the U.S.
|
From page 35... ...
The 2014 committee also recommended that EPA develop templates for structured narrative justifications of the evidence-integration process and conclusions. Approach to Evidence Integration in the 2022 Draft Assessment EPA described evidence integration as a two-step process (Figure III of preamble to the Main Assessment, p.
|
From page 36... ...
The second step of evidence integration brings together the strength of evidence for the human and animal streams and consideration of mechanistic evidence. The description of this step also mentions the coherence of the evidence streams and information on susceptible populations.
|
From page 37... ...
. EPA's inclusion of mechanistic evidence as a separate evidence stream is appropriate, but EPA faced substantial challenges in considering this evidence, especially in the context of systematic review.
|
From page 38... ...
EPA has pioneered the use of mechanistic evidence and the committee evaluated the use of this evidence in the formaldehyde assessment with these challenges in mind. In the 2022 Draft Assessment, EPA classifies mechanistic studies as in vitro or as results of modeling, and assesses them as a separate evidence stream (e.g., Section F.2.4, "Literature Inventory")
|
From page 39... ...
This component of EPA's process is depicted in Figure 2-8. FIGURE 2-8 Dose-response assessment in EPA's systematic review approach.
|
From page 40... ...
study along with the Hanrahan et al. study would affect the candidate reference concentration for sensory irritation, in accordance with the recommendation of the 2014 National Research Council (NRC)
|
From page 41... ...
2022. Principles and framework for assessing the risk of bias for studies included in comparative quantitative environmental systematic reviews.
|
From page 42... ...
2019. Synthe sising quantitative evidence in systematic reviews of complex health interventions.
|
From page 43... ...
2019. Handbook for conducting a literature-based health assessment using OHAT approach for systematic review and evidence integration.
|
From page 44... ...
2014. The Navigation Guide systematic review methodology: a rigorous and transparent method for translating environmental health science into better health outcomes.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.