Residential Radon Exposure and Cigarette Smoking in Association with Lung Cancer: A Matched Case-Control Study in Korea

Abstract

Residential radon exposure and cigarette smoking are the two most important risk factors for lung cancer. The combined effects thereof were evaluated in a multi-center matched case-control study in South Korea. A total of 1038 participants were included, comprising 519 non-small cell lung cancer cases and 519 age- and sex- matched community-based controls. Residential radon levels were measured for all participants. Multivariate logistic regression was used to calculate odds ratios (OR) for lung cancer according to radon exposure (high ≥ 100 Bq/m3 vs. low < 100 Bq/m3), smoking status, and combinations of the two after adjusting for age, sex, indoor hours, and other housing information. The median age of the participants was 64 years, and 51.3% were women. The adjusted ORs (95% confidence intervals [CIs]) for high radon and cigarette smoking were 1.56 (1.03–2.37) and 2.53 (1.60–3.99), respectively. When stratified according to combinations of radon exposure and smoking status, the adjusted ORs (95% CIs) for lung cancer in high-radon non-smokers, low-radon smokers, and high-radon smokers were 1.40 (0.81–2.43), 2.42 (1.49–3.92), and 4.27 (2.14–8.52), respectively, with reference to low-radon non-smokers. Both residential radon and cigarette smoking were associated with increased odds for lung cancer, and the difference in ORs according to radon exposure was much greater in smokers than in non-smokers.

Relationships among Indoor Radon, Earthquake Magnitude Data and Lung Cancer Risks in a Residential Building of an Apulian Town (Southern Italy)

“…Radon-attributable lung cancer deaths for all 66 countries totaled 226,057 in 2012 and represented a median of 3.0% of total cancer deaths [77]. Recently, multiple published studies have measured the risk of developing lung cancer following residential or occupational radon exposure in various regions of the world, as well as the synergistic effect of cigarette smoking and the effect in never-smokers [8][9][10]73,[77][78][79][80][81] as well as analyzing the histological types of lung cancer [82].…”

Radon and Lung Cancer: Current Trends and Future Perspectives

“…The association between radon exposure and lung cancer has been widely reported, and the combined effect of radon and tobacco smoke is thought to be synergic and higher than additive, rising 20 to 25 times higher than the risk of death by lung cancer in smokers exposed to radon beyond 200 Bq/m 3 [11,[75][76][77].…”

“…In 2001, Lagarde et al suggested the existence of a synergistic effect between indoor radon exposure and tobacco smoke with a relative excess risk of 0.29 (95% CI, 0.03-1.24). Moreover, a recent study has described that smokers exposed to radon below 37 Bq/m 3 had a risk of developing lung cancer of 20.16 (95%CI, 3.4-118.6) [39,76,78].…”

“…In addition, tobacco smoke and radon act as co-carcinogens in the early phases of the carcinogenic process. Both of them generate ROS that interact with DNA thought hydroxyl radical attack and radiolysis leading to bulky DNA adducts, with DNA repair pathway saturation and increased apoptosis [76,79]. They are both associated to mutations in KRAS and TP53.…”

Radon—The Element of Risk. The Impact of Radon Exposure on Human Health

“…A similar effect was also shown in humans. In the matched case-control study conducted in Korea it was proved that exposure to residential radon and smoking had a synergistic effect increasing the risk of developing lung cancer [ 130 ].…”