Domestic radon and lung cancer—current status including new evidence from Germany

Abstract

Background: Based on the studies in uranium miners as well as in the general population, domestic radon has been identified as the most important environmental risk factor for lung cancer. In the two recent case-control studies in West and East Germany, the lung cancer risk due to exposure to residential radon was investigated. Methods: From 1990 to 1997, incident lung cancer patients (histologically/cytologically confirmed) as well as a random sample recruited from the population (controls) were interviewed on their residential history, smoking, occupational exposure and other risk factors. Two charcoal canisters and two alpha track detectors (exposure time 3 days, 1 year, respectively) were placed in the present and former dwellings of participants. In the West German study, the evaluation included 1449 cases and 2297 controls; 1053 cases and 1667 controls were recruited in East Germany. Odds ratios (OR) were estimated in a conditional logistic regression model adjusting for smoking and for exposure to asbestos. Results: In the entire West German study area, no odds ratio different from one is found, whereas in the embedded radon-prone matching areas, a clear influence of exposure to radon on the lung cancer risk is observed. The adjusted odds ratios [95% CI] in the radon-prone areas based on the year-long measurement in the last dwelling amount to 1.57 [1.08, 2.27], 1.93 [1.19, 3.13] and 1.93 [0.99, 3.77] for 50–80, 80–140 and over 140 Bq/m 3 compared to 0–50 Bq/m 3. In East Germany, a small influence of exposure to radon on the lung cancer risk is observed in the entire study area. The adjusted odds ratios are 0.97 [0.78, 1.21], 1.05 [0.81, 1.36] and 1.37 [0.97, 1.93] for 50–80, 80–140 and over 140 Bq/m 3 compared to 0–50 Bq/m 3. Considering the exposure during the last 5 to 15 years in the present and past homes as well as time spent at home shows, odds ratios are similar to those mentioned above. Conclusions: The results in the West German radon-prone matching areas and in East Germany are compatible with recent studies from Sweden and England, with the result of a meta-analysis including eight important published studies, as well as with risk models from the analysis of cohorts of miners. Therefore, new evidence of an exposure–response relation within the population is found.