Study type: Epidemiological study (observational study)

Childhood leukemia and magnetic fields in Japan: a case-control study of childhood leukemia and residential power-frequency magnetic fields in Japan epidem.

Published in: Int J Cancer 2006; 119 (3): 643-650

Aim of study (acc. to author)

To investigate whether there is an association between childhood leukemia and residential magnetic fields a case-control study was conducted in Japan.

Endpoint/type of risk estimation

Type of risk estimation: (odds ratio (OR))



Exposure groups

Group Description
Reference group 1 bedroom magnetic field level: below 0.1 μT
Group 2 bedroom magnetic field level: 0.1-0.2 μT
Group 3 bedroom magnetic field level: 0.2-0.4 μT
Group 4 bedroom magnetic field level: above 0.4 μT


Case group

Control group

Study size

Cases Controls
Eligible 781 -
Participants 381 1,097
Participation rate 49 % 29 %
Evaluable 312 603

251 cases with ALL, 61 with AML

Statistical analysis method:

Results (acc. to author)

Only 6 out of 312 cases and 5 out of 603 controls were exposed to more than 0.4 μ magnetic field. An increased risk for acute lymphoblastic leukemia and acute myelocytic leukemia was found for children whose bedrooms had magnetic fields of 0.4 μT or more. Further bias evaluation reviealed no substantial difference in the results.

Limitations (acc. to author)

The authors considered the results were not due to bias alone, although these may be due to chance.

Study funded by

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