International study of childhood leukemia in residences near electrical transformer rooms

Abstract

Overview

This international study was designed to clarify the association between exposure to extremely low frequency magnetic fields (ELF-MF) from electrical transformer rooms and the risk of childhood leukemia. Unlike previous research focusing mainly on power lines, this study included children living in apartment buildings containing built-in transformers, aiming to capture higher exposures while minimizing selection bias.

Methods

• 🔬 Used multi-country, registry-based matched case-control data across five countries.
• 🏠 Children classified according to apartment proximity to transformers: high (above or adjacent), intermediate (same floor), and unexposed (other apartments).
• 📊 Relative risk for leukemia calculated using conditional and mixed logistic regression models.

Findings

• Pooling data yielded 16 intermediate and 3 highly exposed leukemia cases.
• Conditional logistic model:
  • RR for intermediate exposure: 1.0 (95% CI: 0.5, 1.9)
  • RR for high exposure: 1.1 (95% CI: 0.3, 3.8)
• Mixed logistic model:
  • RR for intermediate exposure: 1.4 (95% CI: 0.8, 2.5)
  • RR for high exposure: 1.3 (95% CI: 0.4, 4.4)
• In the country contributing the most data:
  • Intermediate: RR 1.1 (95% CI: 0.5, 2.4)
  • High: RR 1.7 (95% CI: 0.4, 7.2)

Conclusion

While the observed elevated risks for childhood leukemia were weak and confidence intervals were wide, the study cannot exclude a risk similar to that associated with proximity to power lines. Importantly, small case numbers limit definitive conclusions, but the connection between residential ELF-MF exposure and leukemia risk warrants precaution and further research.