Technical Report No. 18-89
The observed relationship between the occurrence of acute radiation sickness and subsequent cancer mortality among A-bomb survivors in Hiroshima and Nagasaki
Neriishi K, Stram DO, Vaeth M, Mizuno S, Akiba SEditor’s note: A publication based on this report was published in Radiat Res 125:206-13, 1991.
Summary
In an analysis of data obtained from the Life Span Study, a follow-up study of a fixed population of 73,330 atomic bomb survivors in Hiroshima and Nagasaki, the slope of a linear dose response between the estimated dose of ionizing radiation and leukemia mortality was found to be steeper (p < 0.001), by a factor of 2.5, among those who reported epilation within 60 days of the bombings, as compared to those who did not experience this acute radiation symptom. For nonleukemic cancer mortality, the dose-response relationship was only slightly affected (p > 0.2) by the presence of epilation.
The results for leukemia were not modified by age or sex and were consistent in both cities. These observations suggest that those individuals who experienced early effects of radiation were more likely to die of leukemia during the follow-up period than individuals who were exposed to the same level of A-bomb radiation but did not develop epilation. The robustness of this finding on the interaction of two difficult but important problems was investigated. These were the validity of a linear dose-response model for leukemia, and the level of assumed precision of the radiation dosimetry system used for assignment of dose estimates to individual survivors. Assuming 35% random dose errors and a dose-response function cubic in dose, the excess relative risk for leukemia was still estimated to be 1.89 times higher for the group with epilation, and the p-value for a test of association between leukemia and epilation remained significant at the 0.10 level. If 50% random dosimetry errors are assumed using the same cubic model, the dose response in the epilation group is estimated to be 1.58 times higher than the others, but is not significant (p < 0.3).
In an analysis of data obtained from the Life Span Study, a follow-up study of a fixed population of 73,330 atomic bomb survivors in Hiroshima and Nagasaki, the slope of a linear dose response between the estimated dose of ionizing radiation and leukemia mortality was found to be steeper (p < 0.001), by a factor of 2.5, among those who reported epilation within 60 days of the bombings, as compared to those who did not experience this acute radiation symptom. For nonleukemic cancer mortality, the dose-response relationship was only slightly affected (p > 0.2) by the presence of epilation.
The results for leukemia were not modified by age or sex and were consistent in both cities. These observations suggest that those individuals who experienced early effects of radiation were more likely to die of leukemia during the follow-up period than individuals who were exposed to the same level of A-bomb radiation but did not develop epilation. The robustness of this finding on the interaction of two difficult but important problems was investigated. These were the validity of a linear dose-response model for leukemia, and the level of assumed precision of the radiation dosimetry system used for assignment of dose estimates to individual survivors. Assuming 35% random dose errors and a dose-response function cubic in dose, the excess relative risk for leukemia was still estimated to be 1.89 times higher for the group with epilation, and the p-value for a test of association between leukemia and epilation remained significant at the 0.10 level. If 50% random dosimetry errors are assumed using the same cubic model, the dose response in the epilation group is estimated to be 1.58 times higher than the others, but is not significant (p < 0.3).