Residential magnetic fields as a risk factor for childhood acute leukaemia: Results from a German population-based case-control study

Our objective was to investigate whether exposure to residential power-freq uency (50 Hr) magnetic fields above 0.2 muT increases a child's risk of leu kaemia and to confirm or reject a finding from a previous German study on t his topic, which reported increased leukaemia risk with exposure to stronge r magnetic fields during the night, A population-based case-control study w as used, covering the whole of the former West Germany. Residential magneti c fields were measured over 24 hr for 514 children with acute leukaemia ide ntified by the German Childhood Cancer Registry and 1,301 control children taken from population registration files. Magnetic fields above 0.2 muT wer e relatively rare in Germany (only 1.5% of the study population). Childhood leukaemia and 24 hr median magnetic fields were only weakly related (OR = 1.55, 95% CI 0.65-3.67). A significant association was seen between childho od leukaemia and magnetic field exposure during the night (OR = 3.21, 95% C I 1.33-7.80). A dose-response-relationship was observed after combining the data of all German studies on magnetic fields and childhood leukaemia. The evidence for an association between childhood leukaemia and magnetic field eposure in our study comes from a measure of exposure during the night. De spite the large size of our study, the results are based on small numbers o f exposed children. If the observed association stands, the effect on a pop ulation level in Germany would be small. (C) 2001 Wiley-Liss, Inc.