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

  • Camilla PedersenEmail author
  • Aslak Harbo Poulsen
  • Naja Hulvej Rod
  • Patrizia Frei
  • Johnni Hansen
  • Kathrine Grell
  • Ole Raaschou-Nielsen
  • Joachim Schüz
  • Christoffer Johansen
Original Article



Evidence of whether exposure to extremely low-frequency magnetic fields (ELF-MF) is related to central nervous system diseases is inconsistent. 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 and epilepsy among 32,006 men employed at the 99 utility companies that supplied Denmark with electricity during the period 1900–1993. Cases were identified in the Danish National Patient Registry and the cohort was followed during 1982–2010. Exposure was estimated from a job-exposure matrix based on company records of job title and area of work and cohort members were allocated to one of three categories (<0.1, 0.1–0.99 and ≥1.0 µT).


For dementia, multiple sclerosis and epilepsy the incidence rate ratios (IRR) were close to unity, but higher for motor neurone disease [IRR 1.24, 95% confidence interval (CI) 0.86–1.79] and lower for Parkinson disease (IRR 0.81, 95% CI 0.67–0.97) among workers exposed to ≥0.1 µT compared with the Danish population. For the highest level of exposure (≥1.0 µT), IRRs of 1.44, 1.78, 1.40 and 1.34 were observed for dementia, motor neurone disease, multiple sclerosis and epilepsy, respectively.


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.


ELF-MF Occupational exposure Central nervous system disease Cohort study 



This work was supported by Danish Energy and by the Danish Cancer Society. We thank Lise Cronberg Salem for information regarding classification of central nervous system diseases and Andrea Meersohn for help in preparing the data.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2017

Authors and Affiliations

  • Camilla Pedersen
    • 1
    Email author
  • Aslak Harbo Poulsen
    • 1
  • Naja Hulvej Rod
    • 2
  • Patrizia Frei
    • 1
  • Johnni Hansen
    • 1
  • Kathrine Grell
    • 1
  • Ole Raaschou-Nielsen
    • 1
  • Joachim Schüz
    • 1
    • 3
  • Christoffer Johansen
    • 1
    • 4
  1. 1.Danish Cancer Society Research CenterCopenhagen ØDenmark
  2. 2.Social Medicine Section, Department of Public HealthUniversity of CopenhagenCopenhagen KDenmark
  3. 3.International Agency for Research on Cancer (IARC), Section of Environment and RadiationLyon Cedex 08France
  4. 4.Oncology Clinic, Finsen Centre, Rigshospitalet 5073University of CopenhagenCopenhagen ØDenmark

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