Lung cancer and residential radon in never-smokers: A pooling study in the Northwest of Spain.

Using a pooled case-control study design, including only never-smokers, we have assessed the association of residential radon exposure with the subsequent occurrence of lung cancer. We also investigated whether residential radon poses a different risk specifically for adenocarcinoma. We pooled individual data from different case-control studies conducted in recent years in Northwestern Spain which investigated residential radon and lung cancer. All participants were never-smokers. Cases had a confirmed biopsy of primary lung cancer. Hospital controls were selected at pre-surgery units, presenting for non-complex surgical procedures. They were interviewed using a standardized instrument. Residential radon was measured using alpha track detectors at the Galician Radon Laboratory at the University of Santiago de Compostela. A total of 1415 individuals, 523 cases and 892 controls were included. We observed an odds ratio of 1.73 (95%CI: 1.27–2.35) for individuals exposed to ≥ 200 Bq/m3 compared with those exposed to ≤100 Bq/m3. Lung cancer risk for adenocarcinoma was 1.52 (95%CI: 1.14–2.02) using the same categories for radon exposure. Residential radon is a clear risk factor for lung cancer in never-smokers. Our data suggest that radon exposure is associated with all histological types of lung cancer and also with adenocarcinoma, which is currently the most frequent histological type for this disease. • Lung cancer in never-smokers comprises approximately 15–25% of lung cancer cases. • The epidemiology of lung cancer in never-smokers is currently little developed. • Residential radon is a clear risk factor for lung cancer in never-smokers. • This risk is associated with almost all histological types of lung cancer. [ABSTRACT FROM AUTHOR]