Study type: Epidemiological study (observational study)

Childhood cancer in relation to a modified residential wire code. epidem.

Published in: Environ Health Perspect 1993; 101 (1): 76-80

Aim of study (acc. to author)

The data of a case-control study on childhood cancer in the Denver metropolitan area, USA, were reanalyzed by use of a modified Wertheimer-Leeper scheme.

Further details

The Wertheimer-Leeper scheme comprises 5 categories: buried, very low current configuration (VLCC), ordinary low current configuration (OLCC), ordinary high current configuration (OHCC), and very high current configuration (VHCC). These categories were dichtomized as low (buried, very low, and ordinary low) and high (ordinary high and very high) wire codes. The modified wire codes analyzed in the present study were derived based on their relations with measured fields. The three categories of the modified wire code are high wire code (HWC, homes within 20 m of a transmission or three-phase primary line), medium wire code (MWC, homes that are not HWC but have a transmission line or three-phase primary line within 46 m or an open secondary line within 26 m), and low wire code (LWC).

Endpoint/type of risk estimation

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



Exposure groups

Group Description
Reference group 1 Wertheimer-Leeper scheme, wire code: buried wire
Group 2 Wertheimer-Leeper scheme, wire code: very low current
Group 3 Wertheimer-Leeper scheme, wire code: ordinary low current
Group 4 Wertheimer-Leeper scheme, wire code: ordinary high current
Group 5 Wertheimer-Leeper scheme, wire code: very high current
Reference group 6 wire code: low
Group 7 wire code: high
Reference group 8 modified wire code: low (LWC)
Group 9 modified wire code: medium (MWC)
Group 10 modified wire code: high (HWC)


Case group

Control group

Study size

Cases Controls
Eligible 356 378
Participants 252 222
Statistical analysis method: (adjustment: )

Conclusion (acc. to author)

The modified wire code generated risk estimates that were precise elevated for the high wire code compared to low wire code classifications. The odds ratios for childhood cancer, leukemia, and brain cancer were significantly elevated. Potential confounding was examined and generally found to be absent.
The reanalysis of the data on childhood cancer and wire configuration codes showed a stronger relationship for the modified wire codes as to the original Wertheimer-Leeper scheme.

Limitations (acc. to author)

Selection bias due to different participation of controls in the study cannot be ruled out.

Study funded by

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