Commentary: childhood cancer near nuclear power stations

Increased incidences of childhood leukemias were first reported near UK nuclear facilities in the late 1980s. Various explanations were offered for these increases; however the UK Government Committee on the Medical Aspects of Radiation in the Environment (COMARE) concluded in a series of reports [1-4] that the causes remained unknown but were unlikely to involve radiation exposures. This was mainly because the radiation exposures from these facilities were estimated to be too low, by two to three orders of magnitude, to explain the increased leukemias.Recently, the KiKK (Kinderkrebs in der Umgebung von KernKraftwerken = Childhood Cancer in the Vicinity of Nuclear Power Plants) study [5,6] has rekindled the childhood leukemia debate. The KiKK study had been established partly as a result of an earlier study by K？rblein and Hoffmann [7] which had found statistically significant increases in solid cancers (54%), and in leukemia (76%) in children aged < 5 within 5 km of 15 German NPP sites. It reported a 2.2-fold increase in leukemias and a 1.6-fold increase in solid (mainly embryonal) cancers among children living within 5 km of all German nuclear power stations. The web publication [8] of the study in December 2007 resulted in a public outcry and media debate in Germany which has received little attention elsewhere.The KiKK case-control study commands attention for a number of reasons. The first is its large size: it examined all cancers at all 16 nuclear reactor locations in Germany between 1980 and 2003, including 1,592 under-fives with cancer and 4,735 controls, with 593 under-fives with leukemia and 1,766 controls. This means that the study is statistically strong and its findings statistically significant. Small numbers and weak statistical significance often limit the usefulness of many smaller epidemiological studies.Second is its authority: it was commissioned in 2003 by the German Government's Bundesamt für Strahlenschutz (BfS, the German Federal Office for