IPSHU English Research Report Series Issue 28
published_at 2012-03

Investigation on circular asymmetry of geographical distribution of mortality risk in Hiroshima atomic bomb survivors

Tonda Tetsuji
Hoshi Masaharu
8.4 MB
While there are a considerable number of studies on the relationship between the risk of disease or death and direct exposure from the atomic bomb in Hiroshima, the risk for indirect exposure caused by residual radioactivity has not yet been fully evaluated. One of the reasons is that risk assessments have utilized estimated radiation doses, but that it is difficult to estimate indirect exposure. To evaluate risks for other causes, including indirect radiation exposure, as well as direct exposure, a statistical method is described here that evaluates risk with respect to individual location at the time of atomic bomb exposure instead of radiation dose. The proposed method is applied to a cohort study of Hiroshima atomic bomb survivors. The resultant contour map suggests that the region north-west to the hypocenter has a higher risk compared to other areas. This in turn suggests that there exists an impact on risk that cannot be explained by direct exposure.
Copyright (c) 2012 Institute for Peace Science, Hiroshima University