Risk Assessment for Benefits Analysis: Conceptual Framework. D. A. Axelrad, K. Baetcke, C. Dockins, C. Griffiths, R. Hertzberg, R. Hill, A. Lowit, P. A. Murphy, N. Owens, N. Simon, L. K. Teuschler, and P. White, US Environmental Protection Agency, DC
Risk Assessment for Benefits Analysis is a multi-disciplinary effort exploring methods for increased integration of human health risk assessment and human health benefits analysis at the U.S. Environmental Protection Agency. In order to quantify health benefits of reduced exposure to environmental contaminants, economists generally rely on dose-response relationships estimated by risk assessors. Further, to be useful for benefits analysis, the health endpoints that are quantified for toxic substances using animal toxicity data must be translated into illnesses or symptoms that are readily understood by and perceptible to the layperson. This presentation will describe the framework for a case study that addresses these issues through a combination of toxicology, epidemiology, statistics and economics. The case study assesses a chemical that affects the thyroid, and considers the benefits for both noncancer health effects (hypothyroidism) and thyroid cancers. The effects are presumed to be due to a mode of action involving interference with thyroid-pituitary functioning that would lead to nonlinear dose-response. The case study uses data from animal testing for cancer (tumor incidence data) and for other key events (e.g., changes in thyroid hormone levels) to estimate dose-response relationships. Human data on thyroid disease are used to link animal dose-response modeling estimates to discrete human effects that can be used in benefits analysis. Finally, available valuation studies are reviewed for applicability to the human thyroid disease outcome (benefits transfer), and opportunities for original research on thyroid effects valuation are identified. The purpose of the case study is to explore new methods for quantifying health benefits, particularly for effects with nonlinear dose-response relationships; applicability of case study methods to other substances and effects will be considered.
Disclaimer: The views expressed in this presentation are those of the authors, and do not necessarily represent the views of the U.S. Environmental Protection Agency.
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