Study type: Epidemiological study (observational study)

A case-control study of childhood leukemia in southern Ontario, Canada, and exposure to magnetic fields in residences. epidem.

Published in: Int J Cancer 1999; 82 (2): 161-170

Aim of study (acc. to author)

To investigate the association between the risk of childhood leukemia and residential exposure to magnetic fields, a population-based case-control study was conducted in Canada.

Further details

Exposure to magnetic fields was assessed by point-in-time measurements inside and outside the residences and by wire-code classification according to Wertheimer-Leeper, Barnes (Wertheimer-Leeper scheme modified by considering underground service) and Kaune-Savitz.

Endpoint/type of risk estimation

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

Exposure

Assessment

Exposure groups

Group Description
Reference group 1 measurement of magnetic flux density in child's bedroom: < 0.03 µT
Group 2 measurement of magnetic flux density in child's bedroom: 0.03 - 0.06 µT
Group 3 measurement of magnetic flux density in child's bedroom: 0.06 - 0.12 µT
Group 4 measurement of magnetic flux density in child's bedroom: ≥ 0.13 µT
Reference group 5 measurement of magnetic flux density, interior average: < 0.04 µT
Group 6 measurement of magnetic flux density, interior average: 0.04 - 0.08 µT
Group 7 measurement of magnetic flux density, interior average: 0.09 - 0.14 µT
Group 8 measurement of magnetic flux density, interior average: ≥ 0.15 µT
Reference group 9 measurement of magnetic flux density, outside: < 0.03 µT
Group 10 measurement of magnetic flux density, outside: 0.03 - 0.07 µT
Group 11 measurement of magnetic flux density, outside: 0.08 - 0.14 µT
Group 12 measurement of magnetic flux density, outside: ≥ 0.15 µT
Reference group 13 Wertheimer-Leeper: very low current configuration (VLCC)
Group 14 Wertheimer-Leeper: ordinary low-current configuration (OLCC)
Group 15 Wertheimer-Leeper: ordinary high-current configuration (OHCC)
Group 16 Wertheimer-Leeper: very-high-current configuration (VHCC)
Reference group 17 Wertheimer-Leeper, modified by Barnes: underground
Group 18 Wertheimer-Leeper, modified by Barnes: very low current configuration (VLCC)
Group 19 Wertheimer-Leeper, modified by Barnes: ordinary low-current configuration (OLCC)
Group 20 Wertheimer-Leeper, modified by Barnes: ordinary high-current configuration (OHCC)
Group 21 Wertheimer-Leeper, modified by Barnes: very-high-current configuration (VHCC)
Reference group 22 Kaune-Savitz: low
Group 23 Kaune-Savitz: medium
Group 24 Kaune-Savitz: high

Population

Case group

Control group

Study size

Cases Controls
Eligible 298 1,133
Participants 203 419
Evaluable 201 406
Statistical analysis method: (adjustment: )

Conclusion (acc. to author)

Magnetic field exposures measured both inside and outside the residences representing at least 70 % of the etiological period showed weak, non-significant associations with childhood leukemia. For children younger than 6 years at diagnosis, an association between outside perimeter measurements of the residence with magnetic fields of 0.15 µT and above and increased leukemia risk was found. The findings did not support an association between childhood leukemia and proximity to power lines with high current configuration.

Study funded by

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