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Occupational exposure to extremely low-frequency magnetic fields and risk for central nervous system disease: an update of a Danish cohort study among utility workers.

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Pedersen C, Poulsen AH, Rod NH, Frei P, Hansen J, Grell K, Raaschou-Nielsen O, Schüz J, Johansen C. · 2017

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Utility workers exposed to magnetic fields above 1.0 µT showed up to 78% higher rates of serious neurological diseases.

Plain English Summary

Summary written for general audiences

Danish researchers followed 32,006 utility workers for three decades, studying exposure to magnetic fields from power lines and electrical equipment. Workers with highest exposures showed 44% higher dementia rates and 78% higher motor neuron disease rates, suggesting occupational magnetic field exposure may increase neurological disease risk.

Why This Matters

This study represents one of the most comprehensive investigations into ELF magnetic field exposure and neurological disease to date. The researchers followed utility workers for nearly 30 years, creating a robust dataset that strengthens the case for EMF-related health effects. What makes these findings particularly concerning is that the highest exposure category (≥1.0 µT) represents levels commonly found near power lines and in some occupational settings. The 78% increase in motor neuron disease risk and 44% increase in dementia risk among the most exposed workers cannot be dismissed as statistical noise. While the confidence intervals for some findings include unity, the consistent pattern across multiple neurological conditions suggests a real biological effect. The reality is that this adds to a growing body of evidence linking EMF exposure to neurological harm, yet regulatory agencies continue to focus primarily on heating effects while ignoring these non-thermal biological impacts.

Exposure Details

Magnetic Field
< 0.0001, 0.0001-0.00099 and ≥ 0.001 mG

Exposure Context

This study used < 0.0001, 0.0001-0.00099 and ≥ 0.001 mG for magnetic fields:

Building Biology guidelines are practitioner-based limits from real-world assessments. BioInitiative Report recommendations are based on peer-reviewed science. Check Your Exposure to compare your own measurements.

Where This Falls on the Concern Scale

Study Exposure Level in ContextStudy Exposure Level in ContextThis study: < 0.0001, 0.0001-0.00099 and ≥ 0.001 mGExtreme Concern - 5 mGFCC Limit - 2,000 mGEffects observed in the No Concern rangeFCC limit is 20,000,000x higher than this level

Study Details

This study updates a previous study of the incidence of such diseases in a large cohort of Danish utility workers by almost doubling the period of follow-up.

We investigated the risks for dementia, motor neurone disease, Parkinson disease, multiple sclerosis...

For dementia, multiple sclerosis and epilepsy the incidence rate ratios (IRR) were close to unity, b...

We observed elevated risks of dementia, motor neurone disease, multiple sclerosis and epilepsy and lower risks of Parkinson disease in relation to exposure to ELF-MF in a large cohort of utility employees.

Cite This Study
Pedersen C, Poulsen AH, Rod NH, Frei P, Hansen J, Grell K, Raaschou-Nielsen O, Schüz J, Johansen C. (2017). Occupational exposure to extremely low-frequency magnetic fields and risk for central nervous system disease: an update of a Danish cohort study among utility workers. Int Arch Occup Environ Health. 2017 Apr 20. doi: 10.1007/s00420-017-1224-0.
Show BibTeX
@article{c_2017_occupational_exposure_to_extremely_691,
  author = {Pedersen C and Poulsen AH and Rod NH and Frei P and Hansen J and Grell K and Raaschou-Nielsen O and Schüz J and Johansen C.},
  title = {Occupational exposure to extremely low-frequency magnetic fields and risk for central nervous system disease: an update of a Danish cohort study among utility workers.},
  year = {2017},
  doi = {10.1007/s00420-017-1224-0},
  url = {https://link.springer.com/article/10.1007/s00420-017-1224-0},
}
DOI: 10.1007/s00420-017-1224-0

Cited By (33 papers)

Quick Questions About This Study

Danish researchers following 32,006 utility workers for 30 years found that those with highest magnetic field exposures (≥1.0 µT) had 44% higher dementia rates compared to the general population, suggesting occupational power line exposure may increase neurological disease risk.
A 2017 Danish study of utility workers found those exposed to magnetic fields ≥1.0 µT had 78% higher motor neuron disease rates. Workers with moderate exposures (≥0.1 µT) showed 24% increased risk compared to the general population.
Danish utility workers exposed to extremely low-frequency magnetic fields ≥1.0 µT showed 40% higher multiple sclerosis rates in a 30-year study. However, workers with lower exposures showed rates similar to the general population.
Research tracking 32,006 Danish utility workers found those with highest magnetic field exposures (≥1.0 µT) had 34% higher epilepsy rates. The study followed workers for three decades to assess long-term neurological disease patterns.
Surprisingly, Danish utility workers exposed to magnetic fields ≥0.1 µT showed 19% lower Parkinson's disease rates compared to the general population. This unexpected finding contrasts with increased risks observed for other neurological conditions in the same study.