Radon in Indoor Spaces An Underestimated Risk Factor for Lung Cancer in Environmental Medicine

Background: Occupational medicine has long recognized radon to be a cause of lung cancer, especially among miners working under ground. Until recently, however, little scientific evidence was available about the risk to the general population caused by indoor radon. Methods: The authors analyzed literature that they found by a selective search in the light of the recently published S1 guideline of the German Society of Occupational and Environmental Medicine (Deutsche Gesellschaft fur Arbeitsmedizin und Umweltmedizin) and a recent publication of the German Commission on Radiological Protection (Strahlenschutzkommission). Results: Exposure to indoor radon and its decay products is a major contributor to the radiation exposure of the general population. In Germany, the mean radiation exposure due to radon in living rooms and bedrooms is about 49 Bq/m(3). It is well documented in the scientific literature that indoor radon significantly increases the risk of lung cancer, probably in a linear dose-response relationship with no threshold. Every 100 Bq/m(3) increase in the radon concentration is estimated to increase the relative risk for lung cancer by 8% to 16%. After cigarette smoking, radon is the second main cause of lung cancer in the general population without occupational exposure. Conclusions: From the point of view of preventive environmental medicine, it is important to identify buildings with high radon concentrations, initiate appropriate measures, and minimize radon exposure, particularly in new buildings.