[Radon and cancer risk: epidemiological studies after occupational or domestic exposure]

The evaluation of cancer risk after exposure to radon is mainly based on the results of uranium miners follow-up. A cohort study on the French uranium miners has demonstrated an excess of lung cancer and of larynx cancer mortality. A linear dose-response relationship has been described between the excess relative risk of lung cancer and the cumulative exposure to radon (poisson regression). This study has contributed to a joint analysis of 11 cohorts of miners, the aim being a more precise evaluation of the different factors able to influence the dose-response relationship between radon and lung cancer mortality. These factors are: age at first exposure, attained age, time since exposure, the pattern of exposure over time and tobacco consumption. The extrapolation of the risk for the general public from the risk estimated after occupational exposure, has to be considered by taking in account several remarks: uranium miners are exposed, beside radon, to two other radiological components, gamma rays and long lived uranium dust, and to other substances specific of the mines, which are absent in the domestic environment but may with radon have an effect on the lung cancer risk. It was impossible to estimate directly, from these uranium miners data, the risk linked to radon for non-smokers and for female population. A case control-study is currently be carrying out in the French hospitals, in order to estimate the risk of lung cancer linked to the last 30 years of radon exposure in the dwellings.