OBJECTIVES: Radon is a ubiquitous occupational and environmental lung carcinogen. We aim to quantify the association between radon progeny and lung cancer mortality in the largest and most up-to-date pooled study of uranium miners. METHODS: The pooled uranium miners analysis combines 7 cohorts of male uranium miners with 7754 lung cancer deaths and 4.3 million person-years of follow-up. Vital status and lung cancer deaths were ascertained between 1946 and 2014. The association between cumulative radon exposure in working level months (WLM) and lung cancer was modelled as the excess relative rate (ERR) per 100 WLM using Poisson regression; variation in the association by temporal and exposure factors was examined. We also examined analyses restricted to miners first hired before 1960 and with <100 WLM cumulative exposure. RESULTS: In a model that allows for variation by attained age, time since exposure and annual exposure rate, the ERR/100 WLM was 4.68 (95% CI 2.88 to 6.96) among miners who were less than 55 years of age and were exposed in the prior 5 to <15 years at annual exposure rates of <0.5 WL. This association decreased with older attained age, longer time since exposure and higher annual exposure rate. In analyses restricted to men first hired before 1960, we observed similar patterns of association but a slightly lower estimate of the ERR/100 WLM. CONCLUSIONS: This new large, pooled study confirms and supports a linear exposure-response relationship between cumulative radon exposure and lung cancer mortality which is jointly modified by temporal and exposure factors.

• Keywords
• Cancer, Miners, Radiation, Radon,
• MeSH
• Cohort Studies MeSH
• Middle Aged MeSH
• Humans MeSH
• Lung Neoplasms * etiology   MeSH
• Neoplasms, Radiation-Induced * epidemiology   etiology   MeSH
• Occupational Diseases * epidemiology   etiology   MeSH
• Occupational Exposure * adverse effects   MeSH
• Apoptosis Regulatory Proteins MeSH
• Radon * adverse effects   MeSH
• Uranium * adverse effects   MeSH
• Check Tag
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, U.S. Gov't, P.H.S. MeSH
• Names of Substances
• Apoptosis Regulatory Proteins MeSH
• Radon * MeSH
• Uranium * MeSH

OBJECTIVES: Radon is carcinogenic, but more studies are needed to understand relationships with lung cancer and extrathoracic cancers at low exposures. There are few studies evaluating associations with cancer incidence or assessing the modifying effects of smoking. METHODS: We conducted a case-cohort study with 16 434 underground uranium miners in the Czech Republic with cancer incidence follow-up 1977-1996. Associations between radon exposure and lung cancer, and extrathoracic cancer, were estimated with linear excess relative rate (ERR) models. We examined potential modifying effects of smoking, time since exposure and exposure rate. RESULTS: Under a simple ERR model, assuming a 5-year exposure lag, the estimated ERR of lung cancer per 100 working level months (WLM) was 0.54 (95% CI 0.33 to 0.83) and the estimated ERR of extrathoracic cancer per 100 WLM was 0.07 (95% CI -0.17 to 0.72). Most lung cancer cases were observed among smokers (82%), and the estimated ERR of lung cancer per 100 WLM was larger among smokers (ERR/100 WLM=1.35; 95% CI 0.84 to 2.15) than among never smokers (ERR/100 WLM=0.12; 95% CI -0.05 to 0.49). Among smokers, the estimated ERR of lung cancer per 100 WLM decreased with time since exposure from 3.07 (95% CI -0.04 to 10.32) in the period 5-14 years after exposure to 1.05 (95% CI 0.49 to 1.87) in the period 25+ years after exposure. CONCLUSIONS: We observed positive associations between cumulative radon exposure and lung cancer, consistent with prior studies. We observed a positive association between cumulative radon exposure and extrathoracic cancers, although the estimates were small. There was evidence that the association between radon and lung cancer was modified by smoking in a multiplicative or super-multiplicative fashion.

• Keywords
• cancer, ionizing, miners, radiation, radon,
• MeSH
• Radon Daughters adverse effects   MeSH
• Adult MeSH
• Miners statistics & numerical data   MeSH
• Incidence MeSH
• Cohort Studies MeSH
• Smoking adverse effects   MeSH
• Middle Aged MeSH
• Humans MeSH
• Lung Neoplasms epidemiology   MeSH
• Neoplasms, Radiation-Induced epidemiology   MeSH
• Neoplasms epidemiology   MeSH
• Occupational Exposure adverse effects   MeSH
• Radon adverse effects   MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Uranium MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Publication type
• Journal Article MeSH
• Research Support, N.I.H., Intramural MeSH
• Research Support, U.S. Gov't, P.H.S. MeSH
• Geographicals
• Czech Republic epidemiology   MeSH
• Names of Substances
• Radon Daughters MeSH
• Radon MeSH
• Uranium MeSH