Home
Epidemiological study (observational study)

Childhood cancer and magnetic fields from high-voltage power lines in England and Wales: a case-control study.

Published in: Br J Cancer 2010; 103 (7): 1122-1127

Aim of study (acc. to author)

The case-control study published by Draper et al (2005) investigating the association between childhood cancer and magnetic fields from power lines was reanalyzed applying another method of exposure assessment. In the cited study, exposure assessment was based on the distance from home address at birth to power lines whereas in the present study the magnetic fields of the home address at birth were calculated for each child.

Endpoint/type of risk estimation

Type of risk estimation:
  • incidence
(relative risk (RR))

Exposure

Assessment

Exposure groups

Reference group 1 magnetic field estimate of home address at birth: < 0.1 µT
Group 2 magnetic field estimate of home address at birth: 0.1 - < 0.2 µT
Group 3 magnetic field estimate of home address at birth: 0.2 - < 0.4 µT
Group 4 magnetic field estimate of home address at birth: ≥ 0.4 µT

Population

  • Group:
    • children
  • Age: 0–14 years
  • Observation period: 1962-1995
  • Study location: UK (England, Wales)

Case group

Control group

  • Selection:
    • registry-based
  • Matching:
    • sex
    • date of birth within 6 months, birth registration district
    • case:control = 1:1

Study size

Cases Controls
Eligible 31,273 -
Evaluable 28,968 28,968
Other: 9653 children with leukemia, 6584 children with CNS/brain tumors, and 12731 children with other types of cancer
Statistical analysis method:
  • conditional logistic regression

Conclusion (acc. to author)

The calculated magnetic fields of 57704 out of 58162 homes were below 0.1 µT.
The estimated relative risk for each 0.2 µT increase in magnetic field was 1.14 for leukaemia (CI 0.57-2.32; 8 cases and 6 controls ), 0.80 for CNS/brain tumors (CI 0.43-1.51; 4 cases and 7 controls), and 1.34 for other cancers (CI 0.84-2.15; 11 cases and 9 controls).
Although not statistically significant, the results slightly strengthen the existing evidence for an association between exposure to magnetic fields and childhood leukaemia. However, exposure to magnetic fields during the year of birth is extremely unlikely to be the whole cause of apparent increase in childhood leukaemia risk observed in the previous case-control study based on the distance of the birth address from power lines. The authors emphasize that very few homes in Britain are exposed to high magnetic fields from power lines. Assuming causality, the estimated attributable risk is below one case of childhood leukemia per year.

Study funded by

  • Department of Health, UK
  • Scottish Executive/Scottish Ministers, UK
  • United Kingdom Department of Health Radiation Protection Programme

Comments on this article

  • Schmiedel S et al. (2010): The association between extremely low-frequency electromagnetic fields and childhood leukaemia in epidemiology: enough is enough?

Related articles