Health risk assessment with multiple reference indices.

Area of Science:

• Environmental Health
• Toxicology
• Risk Assessment

Background:

• Risk assessments are often challenged by conflicting conclusions from multiple reference indices.
• Current practices typically rely on a single reference index, introducing potential bias.
• This limitation hinders comprehensive analysis and consistent decision-making in risk management.

Purpose of the Study:

• To develop a mathematically objective approach for constructing an aggregated risk estimate from multiple reference indices.
• To ensure all available information is incorporated for a more robust risk assessment.
• To enhance consistency and comparability across different studies.

Main Methods:

• The Aggregated Risk Estimate based on Multiple Reference Indices (AREMRI) was developed.
• AREMRI employs a weighted linear combination of risk distributions derived from individual reference indices.
• Weights are determined by the degree of agreement among these distributions, exemplified using benzene inhalation cancer risk assessments from six regulatory agencies' inhalation unit risks (IURs).

Main Results:

• The agreement between single reference index-based risk distributions varied significantly (0.7% to 92%).
• Indices with higher agreement across multiple sources received greater weight in the AREMRI model.
• The AREMRI consistently yielded a risk estimate that was the third highest among the evaluated single-source estimates across all cases.

Conclusions:

• The proposed AREMRI approach enhances risk assessment by providing consistency and direct comparisons between studies.
• It offers valuable insights into uncertainties associated with toxicological reference values.
• This method supports more informed risk assessment and management decisions, particularly when dealing with significant uncertainty.