Lung cancer risk due to radon in dwellings-evaluation of the epidemiological knowledge

Studies on underground miners have shown an increased risk of lung cancer after exposure to high doses of radon and radon daughters. However, in the range of typical indoor radon exposures, there are still uncertainties on the strength of the association between radon exposure and the risk of lung cancer. Since 1990, population-based epidemiological studies have been performed in the USA, Canada, Sweden, Finland, Germany, Czech Republic, Austria, France, Italy, Spain, and China. Some of them did not find an effect, others have shown a statistically significant association of radon exposure and lung cancer risk. The reason for this heterogeneity is found in the different study designs, different ways of measuring radon, different ranges of radon concentrations, varying information on confounding factors, but most importantly limited sample size in most of the individual studies. Therefore, pooling studies are performed now in North America and Europe, which are close to be finished.