Methods to Derive Uncertainty Intervals for Lifetime Risks for Lung Cancer Related to Occupational Radon Exposure

Area of Science:

• Environmental Health
• Occupational Health
• Radiation Epidemiology

Background:

• Lifetime risks quantify health risks from radiation exposure, crucial for radiation detriment assessment and radon dose conversion.
• Occupational radon exposure poses a significant risk for lung cancer mortality.
• Uncertainty intervals and statistical methods for lifetime risk estimates in radon literature are rarely presented.

Purpose of the Study:

• To introduce and discuss novel methods for deriving uncertainty intervals for lifetime lung cancer risk estimates.
• To model uncertainties in risk model parameters and baseline mortality rates.
• To apply these methods to the German "Wismut" uranium miners cohort study.

Main Methods:

• Utilized Approximate Normality Assumption (ANA) methods and Bayesian techniques to quantify uncertainty in risk model parameters.
• Assessed baseline lung cancer mortality rate uncertainty using WHO mortality database information.
• Employed Monte Carlo simulations for all uncertainty assessment methods.

Main Results:

• Uncertainty from risk model parameters was identified as the largest contributor to lifetime risk uncertainty.
• For a specific exposure scenario, the Lifetime Excess Absolute Risk (LEAR) for the "1960+" sub-cohort was 6.70% [3.26; 12.28] using ANA.
• ANA and Bayesian methods yielded similar results, with minor differences across lifetime risk measures.

Conclusions:

• Risk model parameter uncertainty significantly impacts lifetime risk calculations for radon protection.
• ANA methods are practical and recommended for most cases in assessing lifetime risk uncertainty.
• Findings necessitate consideration in developing radiation protection policies based on lifetime risks.