Epidemiological study (observational study)

Electromagnetic field exposures and childhood leukaemia in New Zealand epidem.

By: Dockerty JD, Elwood JM, Skegg DC, Herbison GP

Published in: Lancet 1999; 354 (9194): 1967-1968

Aim of study (acc. to author)

The possible association of electromagnetic field exposures and childhood leukemia is investigated based on the time-weighted average of residental 24-h electric and magnetic field measurements in the bedroom and living room combined for both rooms in comparison to the separate analysis in the former publication.

Endpoint/type of risk estimation

childhood leukemia

Type of risk estimation:

incidence

(odds ratio (OR))

Exposure

Assessment

questionnaire: household appliances: mother's and child's use
measurement: magnetic field, electric field, electromagnetic transient fields for 24 h every 60 sec in child's daytime room and bedroom

Exposure groups

Group	Description
Reference group 1	magnetic field in bedroom and living room, arithmetic mean: < 0.1 µT
Group 2	magnetic field in bedroom and living room, arithmetic mean: 0.1 - < 0.2 µT
Group 3	magnetic field in bedroom and living room, arithmetic mean: ≥ 0.2 µT
Reference group 4	magnetic field in bedroom and living room, arithmetic mean, lowest third: < 0.0214 µT
Group 5	magnetic field in bedroom and living room, arithmetic mean, middle third: 0.0214 to < 0.0590 µT
Group 6	magnetic field in bedroom and living room, arithmetic mean, highest third: ≥ 0.0590 µT
Reference group 7	electric field in bedroom and living room, arithmetic mean, lowest third: < 5.05 V/m
Group 8	electric field in bedroom and living room, arithmetic mean, middle third: 5.05 - < 14.00 V/m
Group 9	electric field in bedroom and living room, arithmetic mean, highest third: ≥ 14.00 V/m

Population

Group:
- children
Age: 0–14 years
Observation period: 1990 - 1993
Study location: New Zealand

Case group

Characteristics: childhood leukemia
Data source: New Zealand Cancer Registry, public hospital admission/discharge computer system, Children's Cancer Registry
Exclusion criteria: non-resident in New Zealand at time of diagnosis, not born in New Zealand, adopted

Control group

Selection:
- population-based
Matching:
- sex
- age
- case:control = 1:1

Study size

	Cases	Controls
Eligible	131	-
Participants	113	113

Statistical analysis method:

conditional logistic regression

(adjustment:

age
sex
mother's education, smoking in pregnancy, household crowding, residence of child on a farm D: Bildungsstand der Mutter, Rauchen während der Schwangerschaft, Größ

)

Results (acc. to author)

The odds ratios in this study were lower than the odds ratios analyzed for the bedroom and living room separately in the former publication. There was no significant association between childhood leukaemia and the time-weighted average of the 50 Hz electric and magnetic fields in the bedroom and living room combined.

Limitations (acc. to author)

Only few children were in the highest exposure category.

Study funded by

A.B. de Lautour Charitable Trust, New Zealand
Cancer Society of New Zealand
Health Research Council of New Zealand
New Zealand Lottery Grants Board
Otago Medical Research Foundation, New Zealand
Otago Medical School (Faculty Bequest Funds), New Zealand
Transpower New Zealand
Variety Handcrafts, New Zealand

Comments on this article

Repacholi MH et al. (1999): Link between electromagnetic fields and childhood cancer unresolved

Zhao L et al. (2014): Magnetic fields exposure and childhood leukemia risk: a meta-analysis based on 11,699 cases and 13,194 controls
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