Abstract: Residential radon exposure is a serious public health concern, and as such appears in the recommendations of
European Code Against Cancer. The objective of this study was to assess the association between residential
radon levels and mortality due to different types of cancer, using misaligned data analysis techniques. Mortality
data (observed cases) for each of the 313 Galician municipalities were drawn from the records of the National
Statistics Institute for the study period (1999?2008). Expected cases were computed using Galician mortality
rates for 14 types of malignant tumors as reference, with a total of 56,385 deaths due to the tumors analyzed.
The effect estimates of indoor radon (3371 sampling points) were adjusted for sociodemographic variables, altitude,
and arsenic topsoil levels (1069 sampling points), using spatial/geostatistical models fitted with stochastic
partial differential equations and integrated nested Laplace approximations. Thesemodels are capable of processing
misaligned data. The results showed a statistical association between indoor radon and lung, stomach and
brain cancer inwomen in Galicia. Apart fromlung cancer (relative risk (RR)=1.09), inwhich a twofold increase
in radon exposure led to a 9% rise inmortality, the association was particularly relevant in stomach (RR=1.17)
and brain cancer (RR=1.28). Further analytical epidemiologic studies are needed to confirm these results, and an assessment should be made of the advisability of implementing interventions targeting such exposure in
higher-risk areas.
