Radon exposure and lung cancer risk Czech cohort study on residential radon

Epidemiological evidence of lung cancer risk from radon is based mainly on studies of men employed underground in mines where exposures are relatively high in comparison to indoor exposure. Nevertheless, direct evidence of risk from residential radon is desirable. In 1990, a study was started comprising 12 000 inhabitants of an area with elevated radon concentrations. The mean level in the houses was higher than general mean of the country by a factor of five. In the period 1961 1995, a total of 173 lung cancers were observed. Comparing to nationally expected numbers ŽE., the observed number ŽO. of cases is elevated ŽO E 1.11., in contrast to generally low figures for cancers other than lung ŽO E 0.85.. Lung cancer risk related to cumulative exposures experienced in the past 5 24 or 5 35 years were both significant. In relation to standard radon progeny concentration 100 Bq m3, the excess relative risk coefficient was 0.103 Ž95% CI, 0.039 0.168., the value somewhat lower than findings in other indoor studies.