Increases in Leukemia in Infants in Wales and Scotland following Chernobyl: Evidence for Errors in Statutory Risk Estimates

After the Chernobyl reactor accident in April 1986, rainfall precipitation caused measurable radioactive contamination of Wales and Scotland. Using risk models developed by themselves and by the International Commission on Radiological Protection, the UK National Radiological Protection Board advised that no measurable increase in leukemia was predicted at exposures which they estimated from measurements of contamination. However, cancer registry data from both the Wales and Scotland registries show a sharp increase in cases of infant leukemia age 0–1 in the eighteen month period January 1st 1987 to June 30th 1988. This period is that in which the birth cohort who were in utero in the exposure period following the fallout would be in the age group 0–1. Compared with an ‘unexposed group’ consisting of the period 1975–1986 the Wales exposed group had a relative risk (RR) of 4.4 (p = 0.004), the Scotland group a RR of 3.7 (p = .001) and the combined Wales and Scotland group an RR of 3.87 (p = .0001). A second unexposed group, those aged 0–1 in 1989–91 had no significant increased risk although after 1991 rates increased slightly. This finding supports earlier reports of infant leukemia effects in Greece, Germany and the U.S. following Chernobyl. The data cannot entirely distinguish between pre-conception or in utero effects but also reported here are increases in very low birth-weight births in Wales following Chernobyl, suggesting a genetic component to both effects. The existence of good quality leukemia and exposure data makes it possible to calculate an error in the presently accepted risk factors for radiation induced leukemia following this kind of exposure of about 100-fold or more. The possibility of errors of this magnitude in the contemporary risk estimates of ionizing radiation effects suggests that a more cautious approach should be exercised to policy decisions about nuclear power options.