Epidemiological study (observational study)

Exposure to residential electric and magnetic fields and risk of childhood leukemia epidem.

By: London SJ, Thomas DC, Bowman JD, Sobel E, Cheng TC, Peters JM

Published in: Am J Epidemiol 1991; 134 (9): 923-937

Aim of study (acc. to author)

The relation between exposure to residential electric and magnetic fields and the risk of childhood leukemia was investigated in a case-control study in California, USA.

Further details

Electric and magnetic field exposure was assessed by 24-hour measurement, spot measurement, Wertheimer-Leeper scheme, and questionnaire about electric appliances use.

Endpoint/type of risk estimation

childhood leukemia

Type of risk estimation:

incidence

(odds ratio (OR))

Exposure

- power transmission line
- other domestic appliance
- residential

Assessment

interview: use of electric appliances (at least once a week)
wire code: Wertheimer-Leeper scheme: overhead transmission and distribution facilities within 150 feet
measurement: electric and magnetic field measurement under child's bed for 24 hours, spot measurements in 3 rooms, in front yard or backyard (indoor appliances off and on) and over water pipe

Exposure groups

Group	Description
Reference group 1	mean of 24-hour magnetic field: 0.0 - 0.67 mG
Group 2	mean of 24-hour magnetic field: 0.68 - 1.18 mG
Group 3	mean of 24-hour magnetic field: 1.19 - 2.67 mG
Group 4	mean of 24-hour magnetic field: ≥ 2.68 mG
Reference group 5	magnetic field of spot measurement in child's bedroom: 0 - 0.31 mG
Group 6	magnetic field of spot measurement in child's bedroom: 0.32 - 0.67 mG
Group 7	magnetic field of spot measurement in child's bedroom: 0.68 - 1.24 mG
Group 8	magnetic field of spot measurement in child's bedroom: ≥ 1.25 mG
Reference group 9	Wertheimer-Leeper scheme: underground and very low
Group 10	Wertheimer-Leeper scheme: ordinary low
Group 11	Wertheimer-Leeper scheme: ordinary high
Group 12	Wertheimer-Leeper scheme: very high
Group 13	self-reported appliance use by child: bedroom air conditioner
Group 14	self-reported appliance use by child: black-and-white television
Group 15	self-reported appliance use by child: electric clock
Group 16	self-reported appliance use by child: color television
Group 17	self-reported appliance use by child: curling iron
Group 18	self-reported appliance use by child: electric blanket
Group 19	self-reported appliance use by child: electric fan
Group 20	self-reported appliance use by child: electric clippers
Group 21	self-reported appliance use by child: electric hair dryer
Group 22	self-reported appliance use by child: electric space heater
Group 23	self-reported appliance use by child: microwave oven
Group 24	self-reported appliance use by child: water bed
Group 25	self-reported appliance use by child: video game
Group 26	self-reported appliance use by mother: water bed
Group 27	self-reported appliance use by mother during pregnancy: bedroom air conditioner
Group 28	self-reported appliance use by mother during pregnancy: electric blanket
Group 29	self-reported appliance use by mother during pregnancy: electric fan
Group 30	self-reported appliance use by mother during pregnancy: electric space heater

Population

Group:
- children
Age: 0–10 years
Observation period: 1980 - 1987
Study location: USA (Los Angeles County, California)

Case group

Characteristics: leukemia
Data source: Los Angeles County Cancer Surveillance Program

Control group

friends of cases or randomly digit dialing
Matching:
- sex
- age
- ethnicity

Study size

	Cases	Controls
Eligible	331	257
Participants	232	232

Statistical analysis method:

logistic regression
Spearman rank correlations

Results (acc. to author)

No clear association between the risk of childhood leukemia and magnetic fields, assessed by 24-hour measurements or spot measurements, was found. Electric fields were not associated with the leukemia risk. An association between the Wertheimer-Leeper wiring configuration classification and the risk of childhood leukemia was observed.
The results support an association between the risk of childhood leukemia and wiring configuration, but not direct measurements of electric and magnetic fields.

Study funded by

Electric Power Research Institute (EPRI), USA

Comments on this article

London SJ et al. (1993): Erratum: Exposure to residential electric and magnetic fields and risk of childhood leukemia
Austin DF (1992): Health and electromagnetic fields
Bracken MB (1992): Reply: "Exposure to residential electric and magnetic fields and risk of childhood leukemia"
Mundt KA (1992): Reply: "Exposure to residential electric and magnetic fields and risk of childhood leukemia" and "case-control study of childhood cancer and exposure to 60-Hz magnetic fields"

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