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

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Authors not listed · 2006

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Japanese children exposed to bedroom magnetic fields above 0.4 microTesla showed nearly 5 times higher acute lymphoblastic leukemia risk.

Plain English Summary

Summary written for general audiences

Japanese researchers studied 312 children with leukemia and 603 healthy controls, measuring magnetic field levels in their bedrooms from power lines and electrical sources. Children exposed to magnetic fields of 0.4 microTesla or higher showed 2.6 times higher risk of leukemia overall, and 4.7 times higher risk specifically for acute lymphoblastic leukemia. This large study adds to growing evidence linking household magnetic field exposure to childhood cancer risk.

Why This Matters

This Japanese study carries particular weight because it was conducted specifically in response to WHO recommendations for research in high-exposure areas. The findings are striking: children sleeping in bedrooms with magnetic fields above 0.4 microTesla faced nearly five times the risk of acute lymphoblastic leukemia, the most common childhood cancer. What makes this especially concerning is that 0.4 microTesla is not an extreme exposure level. Many homes near power lines, electrical panels, or with poor wiring can easily exceed this threshold. The researchers noted that most leukemia cases in the highest exposure category had magnetic field levels "far above" 0.4 microTesla, suggesting a dose-response relationship. This study reinforces why the International Agency for Research on Cancer classified power-frequency magnetic fields as a possible human carcinogen, and why parents should consider measuring magnetic field levels in their children's bedrooms.

Exposure Information

A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 50-60 Hz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 50-60 HzCell phones~1 GHzWiFi2.4 GHz5G mm28 GHzLogarithmic scale

Specific exposure levels were not quantified in this study.

Cite This Study
Unknown (2006). Childhood leukemia and magnetic fields in Japan: a case-control study of childhood leukemia and residential power-frequency magnetic fields in Japan.
Show BibTeX
@article{childhood_leukemia_and_magnetic_fields_in_japan_a_case_control_study_of_childhood_leukemia_and_residential_power_frequency_magnetic_fields_in_japan_ce1449,
  author = {Unknown},
  title = {Childhood leukemia and magnetic fields in Japan: a case-control study of childhood leukemia and residential power-frequency magnetic fields in Japan},
  year = {2006},
  doi = {10.1002/ijc.21374},
  
}
DOI: 10.1002/ijc.21374PubMed: 16496405

Quick Questions About This Study

The study found children with bedroom magnetic field exposure of 0.4 microTesla or higher had significantly increased leukemia risk. Most cases in the highest exposure group had levels far above this 0.4 microTesla threshold, suggesting stronger fields pose greater risks.
Children exposed to 0.4 microTesla or higher magnetic fields showed 2.6 times higher risk for all leukemia types combined, and 4.7 times higher risk specifically for acute lymphoblastic leukemia compared to children with very low exposure below 0.1 microTesla.
The World Health Organization specifically recommended studies in high-exposure areas like Japan. Researchers measured magnetic fields in children's bedrooms because that's where kids spend 8-12 hours daily, making it the most relevant long-term exposure location for health effects.
Yes, the study found acute lymphoblastic leukemia (ALL) showed a much stronger association with magnetic field exposure than other leukemia types. Children with high exposure had 4.7 times higher ALL risk versus 2.6 times higher risk for all leukemias combined.
The study included 312 children newly diagnosed with acute leukemia and 603 healthy controls matched for gender, age and location. This covered areas where 54% of Japanese children live, making it one of the largest childhood leukemia EMF studies conducted.