Mitigating radon in existing housing in Canada: a cost effectiveness analysis

摘要

The percentage of Canadians in 2012 living in homes with radon concentrations above the Radon Guidelines threshold of 200 Bq/m3 was estimated to be 6.9%, but homeowners are responsible for all the mitigation costs and compliance is voluntary. A cost-utility analysis is conducted to determine the incremental cost effectiveness ratios (ICERs) for the gradual implementation of radon screening and mitigation of existing housing in Canada. The structural uncertainty resulting from the choice of model structure is assessed by comparing the results from a Markov cohort model with those from a discrete event simulation. A period life-table analysis is based on data derived from two recent Canadian radon surveys, the BEIR VI exposure-age-concentration model for attributable risk of lung cancer mortality, and Canadian mortality and quality of life data for the 2012 population. A societal perspective, a lifetime horizon and a discount rate of 1.5% are adopted. At a radon mitigation threshold of 100 Bq/m3, the discounted ICER for current rates of screening and mitigation of existing housing compared to no specific radon measures in Canada is $58,866/QALY using a Markov cohort model and $59,556/QALY using discrete event simulation. The interaction of the built and social environment is important to represent when modeling interventions to reduce radon and associated lung cancer. The sensitivity of the ICER estimates to a mitigation tax credit incentive and to the housing stock renewal rate is investigated because renovations rates have recently become higher than new housing starts in Canada as a result of changing housing and employment policies over the last two decades. The mitigation of radon in existing housing in Canada is cost effective at higher radon mitigation thresholds and the cost effectiveness would improve under a theoretical incentive program for home owners to increase the rates of radon testing and mitigation.