Lung cancer in a Czech cohort exposed to radon in dwellings--50 years of follow-up.

The presented study reports lung cancer mortality in a cohort of 11 842 subjects exposed to high levels of radon covering the period 1961-2010. Exposure estimates were based on one year measurements of radon progeny in most houses of the study area (72%), missing values in the studied area were replaced by measurements in proxy houses (9%) and exposures outside the area (19%) were based on country radon mapping. Mean concentration of 448 Bq m(-3) in the study is higher than the country mean by a factor of 5. By 2010, a total of 293 lung cancers were observed. The risk is significantly related to cumulated exposure with ERR/100Bq m(-3) 0.11 (90%CI: 0.04 - 0.25). This value is consistent with the risk coefficients in other indoor studies and also with the risks observed among uranium miners. The present follow-up demonstrated that increased incidence of lung cancer depends mainly on exposure from previous 5-19 years. The relative risk of lung cancer in the present study derived from this model is 1.53 (90%CI: 1.39 - 1.69).