Childhood Cancer and distance from high-voltage power lines – what do the data mean?
Draper and colleagues1 used distance of mother’s home from high-
voltage (HV) overhead transmission lines at the time of her child’s birth
as a proxy for her child’s subsequent power-frequency magnetic field
exposure(reviewed in Ahlbom et al2). As the authors acknowledge, this is
a crude estimate since, in contrast to other more comprehensive reports 2,
no household measurements were taken, no data on more prevalent low-
voltage distribution sources were collected, no information from other
time-points was obtained, and no validatory home visits were carried out.
National data on the distribution of houses in relation to HV lines
in the UK was provided (J Swanson NGT personal communication) to the
United Kingdom Childhood Cancer Study (UKCCS) for their study of power
lines and childhood cancer in order to assess the representativeness of
study subjects 3. These assessments of distance to power lines in the
UKCCS were made for all registered controls, who have been shown to
represent the general population4. A plot of the distributions of the
Draper study leukaemia and non-leukaemia cases and controls, national and
UKCCS populations by distance from HV lines (see figure [corrected figure with different scale on x axis added 20.7.05]) seem to clearly
show that the leukaemia controls in the study from Draper et al are
systematically different. Their positive result over 100m may therefore
be explained not by an excess of cases but by a deficit of controls.
1. Draper G, Vincent T, Kroll ME, Swanson J. Childhood cancer in
relation to distance from high voltage power lines in England and Wales: a
case-control study. Br.Med.J. 2005;330:1290.
2. Ahlbom A, Day N, Feychting M, Roman E, Skinner J, Dockerty J et
al. A pooled analysis of magnetic fields and childhood leukaemia.
3. Skinner J, Maslanyj M, Mee TJ, Allen SG, Simpson J, Roman E et
al. Childhood cancer and residential proximity to power lines. UK
Childhood Cancer Study Investigators. Br.J.Cancer 2000;83:1573-80.
4. UK Childhood Cancer Study Investigators. The United Kingdom
Childhood Cancer Study: objectives, materials and methods. UK Childhood
Cancer Study Investigators. Br.J.Cancer 2000;82:1073-102.
Competing interests: No competing interests