Dose-response modeling of quantitative response data for risk assessment

The current regulation of non-carcinogenic effects has generally been based on dividing a safety factor into an experimental no-observed-effect-level (NOEL), giving a regulatory reference dose (RfD). This approach does not attempt to estimate the risk as a function of dose; it assumes no significant risk for the dose below the RfD. This paper proposes a mathematical model for finding the upper confidence limit on risk and lower confidence limit on dose for quantitative risk assessment when the responses follow a normal distribution. The proposed procedure appears to be conservative; this is supported by results of a simulation study. The procedure is illustrated by application to real data.