Grant Details
Grant Number: |
5R01CA076031-05 Interpret this number |
Primary Investigator: |
Piegorsch, Walter |
Organization: |
University Of South Carolina At Columbia |
Project Title: |
Low Dose Risk Bounds Via Simultaneous Confidence Bands |
Fiscal Year: |
2001 |
Abstract
DESCRIPTION (Adapted from applicant's abstract): Quantifying environmental and
other detrimental risks from exposure to hazardous agents is an important
component in the process of risk evaluation and assessment. The primary goal of
this project is to extend and study statistical confidence bands for use in
low-dose risk extrapolation. Application is directed to environmental and
occupational risk assessment studies where human or animal data are used to set
benchmark or other safe low-dose levels of a hazardous agent, but where study
information is limited to high dose levels of the agent. Methods are considered
for estimating upper confidence limits on predicted risk for various endpoints
measured on both continuous and discrete scales. From the simultaneous
confidence bounds, lower confidence limits on the benchmark dose (BMD)
associated with a particular risk are calculated. An important feature of the
simultaneous construction is that any inferences based on inverting the
simultaneous confidence bounds apply automatically to inverse bounds on the
BMD.
The methodology extends previous results for simultaneous confidence bands to
normally and non-normally distributed data with dose-dependent variance models,
and to higher-dimensional parameter spaces associated with non-linear
dose-response functions. An evaluation phase of the project studies the
small-sample operating characteristics of the new methodology via Monte Carlo
computer calculations, and applies the new methods to existing data for a
number of endpoints encountered in quantitative risk assessment/low-dose
extrapolation problems. The new methods fill existing gaps in low-dose risk
extrapolation, and have application to a wide variety of data-analytic
scenarios in quantitative risk assessment.
Publications
None