Study type: Epidemiological study (observational study)

Residential exposure to electromagnetic fields and childhood leukaemia: a meta-analysis. epidem.

Published in: Bull World Health Organ 1999; 77 (11): 906-915

Aim of study (acc. to author)

A meta-analysis was conducted to examine the association between residential exposure to electromagnetic fields and childhood leukaemia. The following 15 studies were included: USA (Wertheimer et al. 1979), USA (Fulton et al. 1980), Sweden (Tomenius et al.1986), USA (Savitz et al.1988), England (Coleman et al.1989), USA (London et al. 1991), Denmark (Olsen et al. 1993), Sweden (Feychting et al. 1993), Greece (Petridou et al.1993), Eastern USA (Linet et al.1997), Norway (Tynes et al. 1997), Greece (Petridou et al. 1997), Germany (Michaelis et al. 1997), New Zealand (Dockerty et al. 1998), and Finland (Verkasalo et al. 1993).

Further details

Separate meta-analyses were performed based on five different methods of exposure assessment.

Endpoint/type of risk estimation

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

Exposure

Assessment

Exposure groups

Group Description
Reference group 1 wiring configuration codes: low current configuration
Group 2 wiring configuration codes: high current configuration
Reference group 3 distance from power distribution equipment: ≥ 50 m
Group 4 distance from power distribution equipment: < 50 m
Reference group 5 spot measurements of magnetic fields: < 0.2 µT
Group 6 spot measurements of magnetic fields: ≥ 0.2 µT
Reference group 7 24-h measurements of magnetic fields: < 0.2 µT
Group 8 24-h measurements of magnetic fields: ≥ 0.2 µT
Reference group 9 calculated magnetic fields: < 0.2 µT
Group 10 calculated magnetic fields: ≥ 0.2 µT

Population

Statistical analysis method:

Conclusion (acc. to author)

A statistically significant increased risk for childhood leukemia was observed in the meta-analysis of studies using exposure assessment methods based on wire code configuration and 24-h measurements of magnetic fields.A clear trend was observed for more recent studies to be of a better quality.
The authors concluded that an association between residential exposure to electromagnetic fields and childhood leukemia might exist.

Limitations (acc. to author)

Selection bias, exposure misclassification, and confounders in the individual studies cannot be ruled out.

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