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 menemployed underground in mines where exposures are relatively high in comparison to indoorexposure. Nevertheless direct evidence of risk from residential radon is desirable. In 1990, a studywas started comprising 12 000 inhabitants of an area with elevated radon concentrations. The meanlevel in the houses was higher than general mean of the country by factor of five. In the period1961-95, a total of 173 lung cancers were observed. Comparing to nationally expected numbers(E), the observed number (O) of cases is elevated (O/E=1.11) - in contrast to generally low figuresfor cancers other than lung (O/E=0.85). Lung cancer risk related to cumulative exposuresexperienced in the past 5-24 or 5-35 years was both significant. In relation to standard radonprogeny concentration 100 Bq/m3, the excess relative risk coefficient was 0.103 (95% CI: 0.039 0.168), the value somewhat lower than findings in other indoor studies.Running head: Czech cohort study on residential radon and lung cancer