Lung cancer risk at low radon exposure rates in German uranium miners

BACKGROUND: A determination of the risk of lung cancer at low levels of radon exposure is important for occupational radiation protection. METHODS: The risk of death from lung cancer at low radon exposure rates was investigated in the subcohort of 26,766 German uranium miners hired in 1960 or later. RESULTS: A clear association between lung cancer mortality (n=334 deaths) and cumulative exposure to radon in working level months (WLM) was found. The excess relative risk per WLM was 0.013 (95% confidence intervals: 0.007; 0.021). CONCLUSIONS: The present findings provide strong evidence for an increased lung cancer risk after long-term exposure to low radon exposure rates among Wismut miners. The results are compatible to those from residential radon studies and miner studies restricted to low levels.