Study type: Epidemiological study (observational study)

Leukaemia and residence near electricity transmission equipment: a case-control study. epidem.

Published in: Br J Cancer 1989; 60 (5): 793-798

Aim of study (acc. to author)

A case-control study was conducted in south-east England to investigate the association between leukaemia and residence near electricity transmission equipment.

Endpoint/type of risk estimation

Type of risk estimation: (relative risk (RR))

Exposure

Assessment

Exposure groups

Group Description
Group 1 distance from the nearest overhead line: 0 - 24 m
Group 2 distance from the nearest overhead line: 25 - 49 m
Group 3 distance from the nearest overhead line: 50 - 99 m
Reference group 4 distance from the nearest overhead line: ≥ 100 m
Group 5 distance from the nearest electrical substation: 0 - 24 m
Group 6 distance from the nearest electrical substation: 25 - 49 m
Group 7 distance from the nearest electrical substation: 50 - 99 m
Reference group 8 distance from the nearest electrical substation: ≥ 100 m
Group 9 weighted relative exposure index: category 0 (low)
Group 10 weighted relative exposure index: category 1
Group 11 weighted relative exposure index: category 2
Group 12 weighted relative exposure index: category 3
Group 13 weighted relative exposure index: category 4 (high)

Population

Case group

Control group

Study size

Cases Controls
Eligible 811 1,614
Evaluable 771 1,432
Other:

additionally 231 population controls

Conclusion (acc. to author)

Only 0.6 % of the subjects lived within 100 m of an overhead power line. For this group (7 cases and 9 controls) a statistically non-significant evalated relative risk for leukemia was observed (RR 1.45, CI 0.54-3,88). Residence within 50 m to a power line was associated with a relevative risk of 2.0 (CI 0.4-9.0) based on 3 cases and 3 controls.
Over 40 % of the subjects lived within 100 m of an electrical substation. No increased risk of leukemia was observed for this group. Weighted exposure indices calculated on the base of the current load carried by the electrical substations did not materially alter these risk estimates.
A separate analysis for children up to 18 years living within 50 m of a substation showed a non-significant increased relative risk (RR 1.5, CI 0.7-3.4). Since only one case and one control less aged than 18 years lived within 100 m of a power line, no analysis was performed for this group.

Limitations (acc. to author)

The exposure assessment was crude and indirect, therefore the results should be interpreted with caution.

Study funded by

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