Society For Risk Analysis Annual Meeting 2013

Session Schedule & Abstracts

* Disclaimer: All presentations represent the views of the authors, and not the organizations that support their research. Please apply the standard disclaimer that any opinions, findings, and conclusions or recommendations in abstracts, posters, and presentations at the meeting are those of the authors and do not necessarily reflect the views of any other organization or agency. Meeting attendees and authors should be aware that this disclaimer is intended to apply to all abstracts contained in this document. Authors who wish to emphasize this disclaimer should do so in their presentation or poster. In an effort to make the abstracts as concise as possible and easy for meeting participants to read, the abstracts have been formatted such that they exclude references to papers, affiliations, and/or funding sources. Authors who wish to provide attendees with this information should do so in their presentation or poster.

Common abbreviations

Integrating Diverse Streams of Evidence for Chemical Assessments: Getting from Association to Causation, Part II

Room: Key Ballroom 2   1:30 PM - 3:00 PM

Chair(s): Kimberly Wise

Sponsored by DRSG

M3-B.1  13:30  Bradford Hill Viewpoints and Hypothesis-Based Weight of Evidence. Goodman JE*, Rhomberg LR; Gradient

Abstract: In a seminal 1965 paper, Sir Austin Bradford Hill identified nine factors that suggest causation, particularly when evaluating epidemiology data: strength, consistency, specificity, temporality, biological gradient, plausibility, coherence, experiment, and analogy. These "viewpoints" were presented as aids for thinking through the evidence for causality – in more current terms, as guidance for evaluating the weight of evidence. They were not intended as "criteria" – the term most often used to describe them today. Hill said: "What [my nine viewpoints] can do, with greater or lesser strength, is to help us make up our minds on the fundamental question – is there any other way of explaining the set of facts before us, is there any other answer equally, or more, likely than cause and effect?" That is, Hill called for an evaluation of how well patterns among the whole "set of facts before us" can be accounted for. The degree of credence one should place in the causal role of a substance in question is a function of how much more likely it would be for the set of observations to occur if the substance were causal vs. if it were not. This is the guiding principle behind the Hypothesis-Based Weight-of-Evidence (HBWoE) approach. We will describe this approach, and the role of Bradford Hill's viewpoints in it, for evaluating epidemiology data. We will also describe how recently proposed "extended Hill criteria" can be used to conduct an HBWoE evaluation of epidemiology, toxicology, mechanistic, and other kinds of data in an integrated fashion.

M3-B.2  13:50  Integration three ways: Classical versus mode of action approaches to weight of evidence determinations. Borgert CJ*; Applied Pharmacology and Toxicology

Abstract: In scientific investigations, the questions posed - i.e. the hypotheses tested - determine the measurements and conditions under which they are taken, the procedures used to record and analyze data, and the context in which results are interpreted. In risk assessment, the questions addressed are typically articulated in the problem formulation phase. Decades ago, regulatory agencies couched problem formulation according to the questions answerable by the science of the day. As regulatory requirements for risk assessment became codified, so too did the rudiments of problem formulation. Unfortunately, codifying problem formulation prevents risk assessment from evolving to keep pace with scientific advancements. Today, more specific questions can be addressed and answered more precisely with more advanced science, but this science is not being used effectively because typically, the risk assessment problem formulation step still poses antiquated questions. Problem formulation needs to be modernized so that modern science can better inform risk considerations. Using a well-studied chemical, chloroform, as an example, three Weight of Evidence approaches - the classical IRIS Approach, the Human Relevance Framework Approach, and a Hypothesis-Based Mode of Action Approach - are applied, compared, and contrasted. The analysis illustrates why improving the problem formulation phase is critical to making risk assessment more scientifically accurate, more practical, and more relevant for protecting human health and the environment.

M3-B.3  14:10  The EPA Causality Framework for Assessment of Air Pollution-Related Health Effects. Ross MA*, Owens BO, Vandenberg JM; U.S. Environmental Protection Agency

Abstract: The periodic review of U.S. National Ambient Air Quality Standards (NAAQS) for each of the six criteria air pollutants -- ozone, particulate matter, carbon monoxide, nitrogen oxides, sulfur oxides and lead -- starts with the synthesis and evaluation of the most policy-relevant science in Integrated Science Assessments (ISAs). EPA has developed an approach for formal characterization of the strength of the scientific evidence and drawing conclusions on causality for exposure-effect relationships. The framework establishes uniform language concerning causality and brings greater consistency and specificity to the ISAs. EPA drew on relevant approaches for similar scientific decision-making processes by EPA and other organizations. In Findings from multiple lines of evidence -- controlled human exposure, epidemiologic and toxicological studies -- are evaluated and integrated to draw conclusions on health effects with regard to factors such as consistency, coherence and biological plausibility. The relative importance of different types of evidence varies by pollutant or assessment, as does the availability of different types of evidence for causality determination. The use of the framework is demonstrated with several examples of determinations for various health outcomes and pollutants, particularly drawing from the recently-completed ISA for Lead (Pb). Disclaimer: The views expressed are those of the authors and do not necessarily reflect the views or policies of the US EPA.

M3-B.4  14:30  Discussion: Pulling the Pieces Together. Beck NB*; American Chemistry Council

Abstract: This part of the program (the last talk of the double session) will be a discussion and questions-and-answers session to more fully tie the seven previous talks together and to explore the similarities/differences and benefits of each of the approaches that have been discussed.

[back to schedule]