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Cancer & Tumors

Effect of 26 week magnetic field exposures in a DMBA initiation-promotion mammary gland model in Sprague- Dawley rats

No Effects Found

Authors not listed · 1999

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26-week exposure to power line magnetic fields reduced breast cancer rates in chemically-treated rats, contradicting cancer promotion theories.

Plain English Summary

Summary written for general audiences

Researchers exposed 100 female rats to power line frequency magnetic fields (50-60 Hz) for 26 weeks after chemically inducing breast cancer to test whether EMF promotes tumor growth. The magnetic field exposure actually decreased cancer rates compared to unexposed rats, contradicting the hypothesis that these frequencies promote breast cancer.

Why This Matters

This study delivers an unexpected finding in the EMF-cancer research landscape. While some earlier studies suggested 50 Hz magnetic fields might promote chemically-induced breast cancer in rats, this well-designed experiment found the opposite effect. The magnetic field exposures at 1-5 Gauss actually reduced both cancer incidence and total tumor numbers compared to controls. The 1 Gauss exposure level used here is significantly higher than typical household exposures, which rarely exceed 0.01 Gauss except very close to high-current appliances. What makes this particularly noteworthy is the robust methodology with 100 rats per group and 26 weeks of exposure. However, one study doesn't settle the question. The mixed results across different EMF-cancer studies highlight why this remains an active area of research, with some studies showing promotion effects and others, like this one, showing protective or neutral effects.

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 (1999). Effect of 26 week magnetic field exposures in a DMBA initiation-promotion mammary gland model in Sprague- Dawley rats.
Show BibTeX
@article{effect_of_26_week_magnetic_field_exposures_in_a_dmba_initiation_promotion_mammary_gland_model_in_sprague_dawley_rats_ce1564,
  author = {Unknown},
  title = {Effect of 26 week magnetic field exposures in a DMBA initiation-promotion mammary gland model in Sprague- Dawley rats},
  year = {1999},
  doi = {10.1093/CARCIN/20.5.899},
  
}
DOI: 10.1093/CARCIN/20.5.899PubMed: 10334209

Quick Questions About This Study

In this study, rats exposed to 50 Hz magnetic fields at 1-5 Gauss showed significantly lower breast cancer rates than unexposed controls. Cancer incidence dropped from 96% to 85-95% depending on field strength.
The study used 1-5 Gauss magnetic fields, which are 100-500 times stronger than typical household exposures. Most homes have background levels of 0.01 Gauss or less, except very close to electrical appliances.
Both frequencies showed protective effects. 60 Hz at 1 Gauss reduced cancer incidence to 85% and total tumors to 433, compared to 649 tumors in unexposed controls.
DMBA is a standard laboratory chemical used to reliably initiate breast cancer in rats, allowing researchers to study whether magnetic fields promote or inhibit tumor development in a controlled model.
Rats were exposed 18.5 hours per day, 7 days per week for 26 weeks. This intensive exposure schedule was designed to maximize any potential effects from the magnetic fields.