Epidemiological study (observational study)

Exposure to magnetic fields and survival after diagnosis of childhood leukemia: a German cohort study epidem.

By: Svendsen AL, Weihkopf T, Kaatsch P, Schüz J

Published in: Cancer Epidemiol Biomarkers Prev 2007; 16 (6): 1167-1171

Aim of study (acc. to author)

A cohort study was conducted in Germany to investigate the association between magnetic field exposure and survival among children with leukemia. The authors intended to test the hypothesis by Foliart et al. whether exposure to magnetic fields, if it is associated with increased incidence, could also have a relationship with survival after diagnosis of childhood leukemia.

Further details

The data of the cohort study were based on the data of three previous German case-control studies (publication 975, publication 1959, and publication 6207). Follow-up information of the patients were collected about events (death, relapse, and second tumor).

Endpoint/type of risk estimation

childhood leukemia: acute lymphoblastic leukemia

Type of risk estimation:

mortality

(hazard ratio, survival)

Exposure

Assessment

measurement: 24h-measurement in child's bedroom

Exposure groups

Group	Description
Reference group 1	low magnetic field exposure: < 0.1 µT
Group 2	medium magnetic field exposure: 0.1 - < 0.2 µT
Group 3	high magnetic field exposure: ≥ 0.2 µT

Population

Group:
- children
Age: 1–14 years
Characteristics: acute lymphoblastic leukemia
Observation period: July 1988 - June 1993 (Lower Saxony), January 1991 - September 1994 (Berlin), January 1990 - September 1994 (West Germany)
Study location: West-Germany (Lower Saxony, Berlin)
Data source: German Childhood Cancer Registry

Study size

Type	Value
Total	595

Other:

median duration of follow-up: 9.5 years

Statistical analysis method:

Cox proportional regressions analysis

(adjustment:

sex
age at diagnosis, calendar year of diagnosis

)

Results (acc. to author)

Statistically significant elevated hazard ratios were found for magnetic field exposure between 0.1 and 0.2 µT (based on 34 cases with 9 deaths) and non-significantly elevated for exposure above 0.2 µT (based on 18 cases with 4 deaths). The results support the hypothesis that poorer survival among childhood leukemia patients occurred in children exposed to magnetic fields above 0.2 µT.

Limitations (acc. to author)

The results are based on small numbers. A biological mechanism to explain the findings is not known.

Study funded by

Bundesministerium für Umwelt, Naturschutz und Reaktorsicherheit (Federal Ministry of the Environment, Nature Conservation, and Nuclear Safety), Germany
Danish Cancer Society
University of Mainz, Germany

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