Lung cancer risk from radon at low exposures among Czech miners

Results of three studies of carcinogenic effect from occupational exposure to radon are presented in order to compare risks from low and high exposures. By 1995, a total of 888 cases of lung cancer were observed, 771 of them in the cohort followed since 1952. Exposures in this cohort are relatively high (40-80OWLM). The other two cohorts are characteristic by exposures of about an order of magnitude lower. In the previous analyses, numbers of cases in the latter two cohorts were not sufficient to demonstrate any significant findings. In the present follow-up, 170 cases have been observed in exposure categories below 50 WLM, with a significant excess already in the category 10-20 WLM (about 0.1-0.2 Sv in terms of effective dose). The present analyses suggest that the assumption of linear non-threshold relationship is justifiable. (author)