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 ri sk from residential radon is desirable. In 1990, a study was started compri sing 12000 inhabitants of an area with elevated radon concentrations. The m ean level in the houses was higher than general mean of the country by a fa ctor of five. In the period 1961-1995, a total of 173 lung cancers were obs erved. Comparing to nationally expected numbers (E), the observed number (O ) of cases is elevated (O/E = 1.11), in contrast to generally low figures f or cancers other than lung (O/E = 0.85). Lung cancer risk related to cumula tive exposures experienced in the past 5-24 or 5-35 years were both signifi cant. In relation to standard radon progeny concentration 100 Bq/m(3), the excess relative risk coefficient was 0.103 (95% CI, 0.039-0.168), the value somewhat lower than findings in other indoor studies. (C) 2001 Published b y Elsevier Science B.V. All rights reserved.