Leukemia among children near Sellafield nuclear plant. Methods, results and questions of the Gardner case-control study

The epidemiologic studies near the Sellafield plant investigate whether within a given area around the reprocessing plant any increased incidence of disease, especially cancer, can be detected. The studies apply two different methods: (1) Comparison of death rates due to a specific disease, or number of occurrence of disease, in the vicinity of Sellafield with the corresponding data of a defined, artificial population. (2) A case-control study among children with leukemia or lymphoma. The results obtained for the age group of 0-24 years show a dependence of cancer mortality on the social classes. This trend is significant only for all types of leukemia in total, and for lymphoid leukemia. The study results also reveal a significant increase of leukemia incidence in children near the Sellafield plant. As the study does not include individual data, the results are open to a variety of interpretations concerning possible causes. The increased leukemia mortality stated by the study (in 1989) not being explainable alone by enhanced radioactivity levels in the vicinity of the nuclear installations, other approaches for an explanation are discussed. (orig./MG)