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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

Abstract

Purpose

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.

Methods

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).

Results

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.

Conclusions

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.

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Acknowledgements

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.

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Correspondence to Camilla Pedersen.

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Pedersen, C., Poulsen, A.H., Rod, N.H. et al. 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 90, 619–628 (2017). https://doi.org/10.1007/s00420-017-1224-0

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  • DOI: https://doi.org/10.1007/s00420-017-1224-0

Keywords

  • ELF-MF
  • Occupational exposure
  • Central nervous system disease
  • Cohort study