The objective of this study was to assess the
lung cancer risk resulting from indoor
radon exposure in the province of Quebec, Canada, and to evaluate the efficacy of mitigation measures to reduce this exposure. Concentrations of
radon were determined in a representative sample of houses, and the corresponding
lung cancer risk estimates were generated using the BEIR IV model, taking into account smoking, residential mobility, and regional variations in
radon concentrations. Mean (geometric)
radon concentrations in basements (n = 418) and on first floors (n = 319) were, respectively, 34.4 (95% CI-30.6 to 38.8) and 16.5 Bq m(-3) (14.2 to 19.3). A total of 109 deaths from
lung cancer are predicted to occur as a result of this exposure in a cohort of 60,000 people. Detecting all residences with high
radon concentrations (equal to or above 200 Bq m(-3)) and implementing mitigation measures in each of them would reduce by 4 the number of
lung cancer deaths attributable to indoor
radon exposure. A reduction of 0.05% in the prevalence of smoking would prevent as many deaths from
lung cancer as would
radon mitigation. From a public health perspective, in order to reduce mortality from
lung cancer, most efforts should be focused on smoking, not on the relatively minor and hardly preventable population risk arising from household
radon exposure.