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.
Data availability statement
Data are available on reasonable request.
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Contributors KK-R, DBR, ER, DL, JS, PAD, LT, LBZ, MKS-B and MK developed the research questions and designed the study. ER and DL worked on provision of the French data; MKS-B and KK-R worked on provision of the US Colorado Plateau data; JS and CW worked on provision of the US New Mexico data; LBZ worked on provision of the Canadian Eldorado data; PAD worked on provision of the Canadian Ontario data; and VD and NF worked on provision of the Wismut data. SJB, ER, KK-R and DBR were responsible for data management and processing. KK-R produced the initial draft of the manuscript, which was revised and approved by all authors. KKR is the author acting as guarantor.
Funding This work was partly funded by the Centers for Disease Control and Prevention (R03 OH010946). The construction of the French cohort was partially supported by The Institute for Radiological Protection and Nuclear Safety (IRSN). IRSN thanks ORANO for its cooperation in the elaboration of the French cohort. For the US contribution, funding was provided by the National Institute for Occupational Safety and Health. LBZ work was funded and supported by the Centers for Disease Control and Prevention (CDC) in association with the National Institute for Occupational Safety and Health (NIOSH) Grant (R21OH011452). For the Czech cohort, funding was provided by the National Radiation Protection Institute (SURO), grant MV25972-2/OBV.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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