Exposure to Residential Radon and Lung Cancer in Spain:
A Population-based Case-Control Study Juan Miguel Barros-Dios, María Amparo Barreiro, Alberto Ruano-Ravina, and Adolfo Figueiras (May 2002)

The authors conducted a population-based case-control study in northwest Spain to determine the risk of lung cancer associated with exposure to residential radon. The study covered a total of 163 subjects with incident lung cancer and a population sample of 241 cancer-free subjects since 1992 1994.

Odds ratios for radon were estimated using logistic regression adjusted for sex, age, lifetime tobacco use, family history, and habitat. The adjusted odds ratios for the second, third, and fourth quartiles of radon (breakpoints: 37.0, 55.2, and 148.0 Bq/m 3) were 2.73 (95% confidence interval (CI): 1.12, 5.48), 2.48 (95% CI:1.29, 6.79), and 2.96 (95% CI: 1.29, 6.79), respectively.

An additive synergic effect between radon and tobacco was found. The results from this study suggest that, even at concentrations far below official guideline levels, radon may lead to a 2.5-fold rise in the risk of lung cancer. Furthermore, the synergy found between smoking and radon may prove useful when it comes to drafting public health recommendations. AmJEpidemiol 2002;156:548–55.