Residential radon and lung cancer risk: an updated meta- analysis of case-control studies

Background: Numbers of epidemiological studies assessing residential radon exposure and risk of lung cancerhave yielded inconsistent results. Methods: We therefore performed a meta-analysis of relevant published casecontrolstudies searched in the PubMed database through July 2011 to examine the association. The combinedodds ratio (OR) were calculated using fixed- or random-effects models. Subgroup and dose-response analyseswere also performed. Results: We identified 22 case-control studies of residential radon and lung cancer riskinvolving 13,380 cases and 21,102 controls. The combined OR of lung cancer for the highest with the lowestexposure was 1.29 (95% CI 1.10-1.51). Dose-response analysis showed that every 100 Bq/m3 increment inresidential radon exposure was associated with a significant 7% increase in lung cancer risk. Subgroup analysisdisplayed a more pronounced association in the studies conducted in Europe. Studies restricted to female ornon-smokers demonstrated weakened associations between exposure and lung cancer. Conclusions: This metaanalysisprovides new evidence supporting the conclusion that residential exposure to radon can significantlyincrease the risk of lung cancer in a dose-response manner.