Study type: Epidemiological study (observational study)

Magnetic fields and childhood cancer: an epidemiological investigation of the effects of high-voltage underground cables. epidem.

Published in: J Radiol Prot 2015; 35 (3): 695-705

Aim of study (acc. to author)

A case-control study was conducted in the UK to investigate the association between the exposure to magnetic fields of high-voltage underground cables and the risk for childhood cancer.

Further details

Since decades, there is epidemiological evidence of an association between childhood leukemia and exposure to magnetic fields produced by high-voltage overhead lines. However, magnetic fields are not the only factor that varies in the vicinity of power lines, they also produce electric fields and corona ions. Furthermore, they are also visually prominent in their immediate vicinity, thus raising the possibility that they may influence other characteristics of a neighborhood, such as the people who live there or the types of houses that are subsequently built. Therefore it is important to try to separate potential magnetic field effects from non-magnetic field effects.
Underground cables produce also magnetic fields although confined to a smaller distance from the source compared to power lines. Unlike power lines, they produce no electric fields, no corona ions, have essentially no visual presence, and most nearby residents are unaware of their presence. The hypothesis is that if there is an association of childhood leukemia with underground cables, this would almost have to arise as a result of magnetic fields.
This study is based on the same study population as in the previous study by Bunch et al. (2014).

Endpoint/type of risk estimation

Type of risk estimation: (odds ratio (OR))

Exposure

Assessment

Exposure groups

Group Description
Group 1 distance of address at birth to nearest underground cable: 0 - 9.9 m
Group 2 distance of address at birth to nearest underground cable: 10 - 19.9 m
Group 3 distance of address at birth to nearest underground cable: 20 - 49.9 m
Group 4 distance of address at birth to nearest underground cable: 0 - 49.9 m
Group 5 distance of address at birth to nearest underground cable: 50 - 99.9 m
Group 6 distance of address at birth to nearest underground cable: 100 - 199.9 m
Group 7 distance of address at birth to nearest underground cable: 200 - 499.9 m
Reference group 8 distance of address at birth to nearest underground cable: ≥ 500 m
Group 9 magnetic flux density: > 0.4 µT
Group 10 magnetic flux density: 0.2 - 0.39 µT
Group 11 magnetic flux density: 0.1 - 0.19 µT
Reference group 12 magnetic flux density: < 0.1 µT

Population

Case group

Control group

Study size

Cases Controls
Eligible 55,525 116,815
Statistical analysis method: (adjustment: )

Conclusion (acc. to author)

No association between risk of the childhood leukemia and exposure to magnetic fields based on distance or magnetic flux densities estimations was found. No convincing pattern of risks for any other cancer was observed.
The authors conclude that the absence of risk detected in relation to underground cables tends to add to the argument that any risks from overhead lines may not be caused by magnetic fields.

Limitations (acc. to author)

Few children were exposed to magnetic fields from underground cables limiting the statistical power.

Study funded by

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