Authors' reply

摘要

We agree with Jun Deng and colleagues that the risk of leukaemia varies with age at exposure to radiation. Although there was no clear evidence of this in our study, we noted that it might just reflect insufficient statistical power to examine subgroup effects. Our dosimetric phantoms were developed to take account of changes in red bone marrow during childhood.1 Even if there is large variation in the rate of these changes between children, the associated reduction in the accuracy of our dosimetry is unlikely to account for the lack of a relation between leukaemia risk and age at exposure.