International study of childhood leukemia in residences near electrical transformer rooms

Catherine M Crespi; Madhuri Sudan; Jukka Juutilainen; Päivi Roivainen; Ronen Hareuveny; Anke Huss; Shaiela Kandel; Henrike E Karim-Kos; György Thuróczy; Zsuzsanna Jakab; Ben D Spycher; Benjamin Flueckiger; Roel Vermeulen; Ximena Vergara; Leeka Kheifets

doi:10.1016/j.envres.2024.118459

International study of childhood leukemia in residences near electrical transformer rooms

Environ Res. 2024 Feb 11:249:118459. doi: 10.1016/j.envres.2024.118459. Online ahead of print.

Authors

Affiliations

¹ University of California Los Angeles Fielding School of Public Health, 650 Charles E Young Dr S, Los Angeles, CA, 90095, USA. Electronic address: ccrespi@ucla.edu.
² University of California Los Angeles Fielding School of Public Health, 650 Charles E Young Dr S, Los Angeles, CA, 90095, USA; Kaweah Health Medical Center, Visalia, CA, USA. Electronic address: msudan@g.ucla.edu.
³ University of Eastern Finland, Department of Environmental and Biological Sciences, Kuopio, Finland. Electronic address: jukka.juutilainen@uef.fi.
⁴ University of Eastern Finland, Department of Environmental and Biological Sciences, Kuopio, Finland. Electronic address: paivi.roivainen@uef.fi.
⁵ Radiation Safety Division Soreq NRC, Yavne, Israel. Electronic address: ronen@soreq.gov.il.
⁶ Institute for Risk Assessment Sciences, Utrecht University, Utrecht, the Netherlands. Electronic address: a.huss@uu.nl.
⁷ Independant Researcher, Israel. Electronic address: Shaielak@gmail.com.
⁸ Princess Máxima Center for Pediatric Oncology, Utrecht, the Netherlands. Electronic address: h.e.karim-kos@prinsesmaximacentrum.nl.
⁹ National Center for Public Health and Pharmacy, Budapest, Hungary. Electronic address: thuroczy.gyorgy@nngyk.gov.hu.
¹⁰ National Childhood Oncologic Registry, Department of Pediatrics, Semmelweis University, Budapest, Hungary. Electronic address: dr.jakab.zsuzsa@gmail.com.
¹¹ Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland. Electronic address: ben.spycher@unibe.ch.
¹² Swiss Tropical and Public Health Institute, Allschwil, Switzerland; University of Basel, Basel, Switzerland. Electronic address: benjamin.flueckiger@swisstph.ch.
¹³ Institute for Risk Assessment Sciences, Utrecht University, Utrecht, the Netherlands. Electronic address: r.c.h.vermeulen@uu.nl.
¹⁴ University of California Los Angeles Fielding School of Public Health, 650 Charles E Young Dr S, Los Angeles, CA, 90095, USA. Electronic address: xvergara@ucla.edu.
¹⁵ University of California Los Angeles Fielding School of Public Health, 650 Charles E Young Dr S, Los Angeles, CA, 90095, USA. Electronic address: kheifets@ucla.edu.

PMID: 38346482
DOI: 10.1016/j.envres.2024.118459

Abstract

Objectives: New epidemiologic approaches are needed to reduce the scientific uncertainty surrounding the association between extremely low frequency magnetic fields (ELF-MF) and childhood leukemia. While most previous studies focused on power lines, the Transformer Exposure study sought to assess this association using a multi-country study of children who had lived in buildings with built-in electrical transformers. ELF-MF in apartments above built-in transformers can be 5 times higher than in other apartments in the same building. This novel study design aimed to maximize the inclusion of highly exposed children while minimising the potential for selection bias.

Methods: We assessed associations between residential proximity to transformers and risk of childhood leukemia using registry based matched case-control data collected in five countries. Exposure was based on the location of the subject's apartment relative to the transformer, coded as high (above or adjacent to transformer), intermediate (same floor as apartments in high category), or unexposed (other apartments). Relative risk (RR) for childhood leukemia was estimated using conditional logistic and mixed logistic regression with a random effect for case-control set.

Results: Data pooling across countries yielded 16 intermediate and 3 highly exposed cases. RRs were 1.0 (95% CI: 0.5, 1.9) for intermediate and 1.1 (95% CI: 0.3, 3.8) for high exposure in the conditional logistic model. In the mixed logistic model, RRs were 1.4 (95% CI: 0.8, 2.5) for intermediate and 1.3 (95% CI: 0.4, 4.4) for high. Data of the most influential country showed RRs of 1.1 (95% CI: 0.5, 2.4) and 1.7 (95% CI: 0.4, 7.2) for intermediate (8 cases) and high (2 cases) exposure.

Discussion: Overall, evidence for an elevated risk was weak. However, small numbers and wide confidence intervals preclude strong conclusions and a risk of the magnitude observed in power line studies cannot be excluded.

Keywords: Childhood leukemia; Extremely low frequency; Indoor transformer stations; Magnetic fields; Multi-country study; Pooled analysis.