Letters to the Editor Author’s Response Comments on the study of McGeoghegan et al.

findings of our recent study of male workers at British Nuclear Fuels plc2 should be treated with cau-tion in respect of any causal interpretation, and hope that this was clear to readers of our article. We also agree with the comments of Little, Tawn, Tzoulaki et al. that studies of radiotherapy patients3, whilst important in their own right, are unlikely to assist with the question of whether chronic occupa-tional exposure to ionizing radiation can cause increased risks of circulatory disease (or other non-cancer diseases), as operation of common biological mechanisms in these two very different exposure regimes cannot reliably be inferred. However, we point out that the results of the meta-analysis reported by Little, Tawn, Tzoulaki et al. mus