Lung Cancer and Radon: Pooled Analysis of Uranium Miners Hired in 1960 or Later

Abstract

Background: Despite reductions in exposure for workers and the general public, radon remains a leading cause of lung cancer. Prior studies of underground miners depended heavily upon information on deaths among miners employed in the early years of mine operations when exposures were high and tended to be poorly estimated. Objectives: To strengthen the basis for radiation protection, we report on the follow-up of workers employed in the later periods of mine operations for whom we have more accurate exposure information and for whom exposures tended to be accrued at intensities that are more comparable to contemporary settings. Methods: We conducted a pooled analysis of cohort studies of lung cancer mortality among 57,873 male uranium miners in Canada, Czech Republic, France, Germany, and the United States, who were first employed in 1960 or later (thereby excluding miners employed during the periods of highest exposure and focusing on miners who tend to have higher quality assessments of radon progeny exposures). We derived estimates of excess relative rate per 100 working level months (ERR/100 WLM) for mortality from lung cancer. Results: The analysis included person-years of observation and 1,217 deaths due to lung cancer. The relative rate of lung cancer increased in a linear fashion with cumulative exposure to radon progeny (ERR/100 ; 95% CI: 0.89, 1.88). The association was modified by attained age, age at exposure, and annual exposure rate; for attained ages , the ERR/100 WLM was 8.38 (95% CI: 3.30, 18.99) among miners who were exposed at of age and at annual exposure rates of working levels. This association decreased with older attained ages, younger ages at exposure, and higher exposure rates. Discussion: Estimates of association between radon progeny exposure and lung cancer mortality among relatively contemporary miners are coherent with estimates used to inform current protection guidelines. https://doi.org/10.1289/EHP10669

Effects of spatial variation in dose delivery: what can we learn from radon-related lung cancer studies?

“…Based on the considerably increased data base compared with previous pooled studies, the PUMA study allows for a more detailed investigation of radon-related health risks. Estimates of the radon-related lung cancer risk among relatively contemporary miners in PUMA are coherent with previous results (Richardson et al 2022 ).…”

Radon and lung cancer in the pooled uranium miners analysis (PUMA): highly exposed early miners and all miners

“…The pre-1960 hires have an impact on the PUMA overall summary estimate of association, and also influence estimates of trends in time since exposure and exposure rate within the full cohort. A separate analysis on the subset of miners hired after 1960 provides understanding of the effects of chronic low exposure rate scenarios experienced by more contemporary miners with high-quality exposure estimates 25…”

“…In addition, in this analysis, we adjusted for calendar period at risk, and we also adjusted for duration of employment as a means of controlling for healthy worker survivor bias, which may be substantial in uranium miners 24. All models are linear ERR models; this decision was based on evaluations of linearity published in prior PUMA analyses,25 the results of the BEIR IV analyses,1 and from evidence of linearity from several cohorts within PUMA 4 22 26…”

The Epidemiology of Lung Cancer- How Much Have We Discovered?

“…However, lung cancer existed as early as 1500 when a particular attention was given to miners in two regions of Germany and Czechoslovakia who developed a deadly lung disease and was named "Bergkrankheit" or mountain sickness [9]. The disease lasted for 25 years and killed 60-80% of all miners, resulting in lung cancer recognized as an occupational disease and suspecting that arsenic might be involved in the disease etiology [9] .Furthermore, there was a surge in the demand for uranium following the World War II, when politicians called for the development of nuclear weapons, resulting in the death of more miners without any accountability for protecting them [9,12].…”