A comparison of the apparent risks of childhood leukaemia from parental exposure to radiation in the six months prior to conception in the Sellafield workforce and the Japanese bomb survivors

Abstract

The cases of childhood leukaemia found among children of the Sellafield workforce and those observed in the offspring of the Japanese bomb survivors are analysed using both exponential and linear forms of a relative risk model and employing dose estimates for the period six months pre-conception. The leukaemia relative risk coefficients for paternal (whole-body) exposure in this pre-conception period for children of Sellafield workers are found to be statistically incompatible with the (gonadal dose) coefficients applying to the offspring of the bomb survivors born in the period May 1946 to December 1946, i.e. born 9 to 16 months after the bombings. The incompatibility does not depend on whether the risks in the Japanese children are assumed to be a function simply of paternal gonadal dose or of combined paternal and maternal gonadal dose. This finding is also relatively robust to dosimetric uncertainties in the group of Sellafield fathers and to the addition of extra cases in the offspring of parents in the highest dose groups of both data sets.