Epidemiological evidence of lung cancer risk from random is based mainly on
studies of male miners. Recent results of one such study of Czech uranium
miners who were restricted to lower exposure rates are reported. Two main f
actors that generally influence radiogenic risk of cancer, time since expos
ure and age at exposure, are analyzed. New analyses in the form of a relati
ve risk model confirmed the strong decreasing effect with time since exposu
re that was observed earlier. In addition, a significant dependence on age
at exposure was observed, This pattern of decreasing relative risk with inc
reasing age at irradiation is consistent with observations in A-bomb surviv
ors and irradiated patients. Similar analyses were performed for the two mo
st frequent histological types of bronchogenic carcinoma, epidermoid and sm
all cell. The general pattern of the risk for these two types was found to
be similar to that for lung cancer overall. Nevertheless, differences were
observed between these two types in the magnitude of the risk coefficients
and in the latent period, The effect of radon exposure was found to be stro
nger but briefer for the small cell type. The effect of smoking was not exa
mined in this study, as such data were not available. (C) 1999 by Radiation
Research Society.