Childhood leukaemia in the vicinity of German nuclear power plants - some missing links

A recent epidemiological study in Germany, the so-called KiKK study, came to the conclusion that there was a relationship between a child's risk of contracting leukaemia in the first 5 years of life and the distance of its residence from the nearest nuclear power plant. The risk of children inside a 5 km radius was found to be 2.19 times that of children outside, with a lower 95% confidence limit of 1.51. The study seems to be epidemiologically sound and solid, and its results agree with earlier evidence about childhood leukaemia in the vicinity of nuclear installations. It does not show, however, nor does it at all claim to show, that the phenomenon was due to radiation exposure. The measured doses in the area around German nuclear power plants are at least a factor 1000 smaller than what would be needed to explain the number of leukaemia cases observed. Additional evidence suggests that the main effect was a shift of the age distribution towards younger ages, with the overall incidence for all age groups not affected, which would be rather unexpected as a radiation effect. Still other studies have shown that elevated risks can even be observed around so-called “planning sites”, where no nuclear facility has ever been built. It thus seems justified to speak of “missing links” between the elevated risk of childhood leukaemia around nuclear power plants on the one hand, and the radiation exposure caused by their normal operation on the other.