What are the major findings among the Japanese atomic bomb survivors?
The main radiation effect has been the induction of cancer. Up to 2000 – in other words, 55 years after the bombings of Hiroshima and Nagasaki – the excess number of deaths from all cancers other than leukaemia was estimated to be about 480 in a population of around 86,000; this represents about 8% of all such deaths among the, roughly, 48,000 survivors with a radiation dose greater than zero. In contrast, the excess number of leukaemia deaths in this group of survivors – estimated to be around 90 – represents over 45% of all leukaemia deaths. The magnitude of the excess increases with increasing dose. Analyses of such data have allowed the construction of models to describe how radiation-induced cancer risks vary according to dose, as well as factors such as age at exposure, time since exposure and sex. Data on cancer incidence among the survivors (ie both fatal and non-fatal cases) have also been analysed, since they provide more information on cancers that are rarely fatal, such as
