Lung cancer mortality attributable to residential radon exposure in Spain and its regions.

Lung cancer has the highest cancer mortality rate in developed countries. The principal risk factor for lung cancer is tobacco use, with residential radon being the leading risk factor among never smokers and the second among ever smokers. We sought to estimate mortality attributable to residential radon exposure in Spain and its Autonomous Regions, with correction for dwelling height and differentiation by tobacco use. We applied a prevalence-based method for estimating attributable mortality. For estimations, we considered exposure to radon in the different Autonomous Regions corrected for dwelling height, using the National Statistics Institute Housing Census and prevalence of tobacco use (never smokers, smokers and ex-smokers). The results showed that 3.8% (838 deaths) of lung cancer mortality was attributable to radon exposure of over 100 Bq/m3, a figure that rises to 6.9% (1,533 deaths) when correction for dwelling height is not performed. By Autonomous Region, the highest population attributable fractions, corrected for dwelling height, were obtained for Galicia, Extremadura, and the Canary Islands, where 7.0, 6.9, and 5.5% of lung cancer mortality was respectively attributable to radon exposure. The greatest part of the attributable mortality occurred in men and among smokers and ex-smokers. Residential radon exposure is a major contributor to lung cancer mortality, though this contribution is highly variable among the different territories, indicating the need for targeted prevention policies. Correction of estimates for dwelling height is fundamental for providing reliable estimates of radon-attributable mortality.