[Residential radon and lung cancer. An ecologic study in Galicia, Spain]

Residential radon is the second cause of lung cancer and the first in never smokers. Galicia is a high radon emission area. The objective of this study is to analyze the relationship between municipal lung cancer mortality and residential radon in Galician municipalities.

We performed an ecologic study including 192 municipalities with at least 3 residential radon measurements. The observed number of lung cancer deaths was obtained from the Galician Mortality Registry. Afterwards, we calculated the standardized mortality ratios (SMRs) of lung cancer for males and females for the period comprising 1980-2009. Median municipal residential radon concentrations were correlated with lung cancer SMRs.

Median residential radon concentration for the included municipalities was 75 Bq/m(3), with an interquartile range of 40.7 to 154 Bq/m(3). The correlation between lung cancer SMRs and municipal radon concentration was statistically significant for males (P=.023) whereas it did not reach statistical significance for females (P=.087).

There exists an association between municipal residential radon and lung cancer mortality in Galicia for males, though for women the association is not statistically significant. These results suggest that residential radon could raise the risk of lung cancer in males, though for females no association is evident.