A Cohort Study on Alzheimer's Disease in Relation to Residential Magnetic Fields From Indoor Transformer Stations

Authors: Liimatainen A, Roivainen P, Juutilainen J, Höytä A, Naarala J

Year: 2025 Dec

Category: Epidemiology

Journal: Bioelectromagnetics

DOI: 10.1002/bem.70031

URL: https://onlinelibrary.wiley.com/doi/10.1002/bem.70031

Abstract

Overview

Meta-analyses of epidemiological studies have suggested that Alzheimer's disease (AD) may be linked with exposure to extremely low frequency (ELF) magnetic fields (MF). This study is the first to investigate the association of AD with exposure to residential ELF MFs from indoor transformer stations, utilizing a cohort design specifically engineered to avoid limitations of prior research.

Study Design and Methods

  • All participants lived in buildings containing indoor transformer stations.
  • MF exposure assessment was based on apartment location in relation to the transformer room.
  • AD patient identification relied upon Drug Purchase and Reimbursement Registers.
  • Of 155,562 individuals, 5652 (111,357 person-years) next to transformer stations were considered exposed; 115,772 (2,289,526 person-years) on higher floors served as referents.
  • Cox proportional hazard models examined associations between MF exposure and AD incidence.

Findings

  • The hazard ratio (HR) for AD among those exposed to residential ELF MFs was 1.02 (95% CI: 0.85-1.22), indicating no significant association.
  • Duration of residence near transformer stations did not materially impact AD risk.
  • The HR was slightly but not significantly higher (HR 1.22, 95% CI: 0.94-1.57) for subjects whose residence began prior to age 50.
  • Results did not replicate positive associations reported by previous occupational or residential MF exposure studies.

Conclusions

  • No evidence was found linking high-level residential ELF MF exposure from indoor transformer stations to increased risk of AD.
  • Authors recommend future research to examine occupational ELF MF exposures and potential diurnal (night vs day) differences in MF risk for AD.
Alzheimer's disease magnetic fields ELF residential exposure transformer stations cohort study neurodegenerative risk
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