The present study is based on 9978 Czech uranium miners with 1141 lung cancer deaths observed in an updated follow-up 1952-2010 and corresponding to 31 years of mean follow-up. The objectives of the study are to obtain more reliable estimates for the exposure-response relationship, including factors that modify this relationship. Lung cancer in relation to cumulative exposure to radon decay products is linear with substantial modifications by time since exposure, age at exposure and exposure rate using exposure windows. The crude excess relative risk (ERR) per unit exposure in working level months (WLM) in the cohort is 0.0097 (90% confidence interval (CI) 0.0074-0.0127). The ERR/WLM corresponding to exposure rates below 7 working levels (WL) is substantially higher - 0.0145 (90% CI 0.0109-0.0193). In the final model, the inverse effect of exposure rate is observed for high exposure rates >7 WL with the ERR/WLM reduced to 31%. The ERR/WLM decreases to 32% and 9% in periods 20-29 and 30 +years since exposure in comparison to the period of 5-19 years since exposure. Simultaneously, the ERR/WLM decreases with age at exposure - 63% and 49% at ages 30-39 and 40 +years in comparison to age at exposure <30 years.

National Radiation Protection Institute Bartoskova 28 Prague Czech Republic

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