Magnetic fields from indoor transformer stations and risk of cancer in adults: a cohort study

Authors: Juutilainen J, Khan MW, Naarala J, Roivainen P

Year: 2024 Nov 18

Category: Epidemiology

Journal: Occupational and Environmental Medicine

DOI: 10.1136/oemed-2024-109466

URL: https://pubmed.ncbi.nlm.nih.gov/39557565/

Abstract

Overview

This cohort study aimed to address the association between exposure to extremely low frequency (ELF) magnetic fields (MF) from residential indoor transformer stations and cancer risk in adults. Previous studies in this area have often suffered from limitations such as low exposure levels and various biases.

Methods

The cohort was composed of individuals who resided in buildings with indoor transformer stations in Finland between 1971 and 2016. Their MF exposure was based on their apartment's proximity to the transformer room. Cancer diagnoses data were obtained from the Finnish Cancer Registry. The association of MF exposure with overall cancer as well as specific cancers was evaluated using Standardized Incidence Ratios (SIR) and 95% confidence intervals.

Findings

  • SIR for all primary cancer sites was 1.01 (95% CI 0.93 to 1.09), indicating no overall increase in cancer risk.
  • An elevated risk of digestive organ cancers was detected with a SIR of 1.23 (95% CI 1.03 to 1.46).
  • Gallbladder cancer risk was notably higher (SIR 3.92, 95% CI 1.44 to 8.69).
  • Among men exposed during childhood, an increased risk of testicular cancer was observed, but this may be influenced by confounding factors such as residence on the lowest floors.
  • No significant associations were observed for other primary cancer sites.

What Is Already Known

  • ELF magnetic fields are classified as possibly carcinogenic, with strongest evidence for childhood leukaemia and inconsistent evidence for adult cancers.

What This Study Adds

  • This unique database and study design overcame many limitations typical in earlier research.
  • The results suggest a potential link between MF exposure and digestive organ cancers.
  • No link was observed for overall adult cancer risk.

Conclusion & Policy Implications

While overall cancer risk was not increased by residential MF exposure, the significant association with digestive organ cancers is a novel and concerning finding, highlighting the need for further research in this area. This study also includes higher exposure levels than previous ones, making its findings especially relevant for EMF-related health risk assessment and risk communication.

ELF magnetic fields cancer risk transformer stations digestive organ cancers residential exposure cohort study adult cancer
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