overview (this page) | details of distance results | details of magnetic field results
The Childhood Cancer Research Group at the University of Oxford is conducting a study on cancer rates in relation to power lines. The study is sometimes called the "CCRG" study or sometimes the "Draper" study after Dr Gerald Draper, the Director of the CCRG (now retired) and the lead author of the first publication.
The study has produced a sequence of papers which we summarise here with more details on separate pages for the key results papers. See also the abstracts of these papers.
The "distance" results paper
This paper was published in the British Medical Journal on 3 June 2005 and gave results for distance from 275 kV and 400 kV power lines in England and Wales.
See:
The results in a nutshell
- Children who lived within 200 m of high-voltage power lines had a relative risk of leukaemia of 1.69 (95% confidence interval 1.13 to 2.53)
- Those born between 200 and 600 m had a relative risk of 1.23 (1.02 to 1.49).
- There was a significant (P<0.01) trend in risk in relation to the reciprocal of distance from the line.
- No excess risk in relation to proximity to lines was found for other childhood cancers.
- The results do not seem to be compatible with the existing data on magnetic fields and cancer because they extend too far from the line. This was explored more fully in the subsequent magnetic-fields paper.
- There is no evidence the results are explained by the “corona ion” hypothesis
Review paper
This paper, published in the Annals of the New York Academy of Sciences in 2006, reviewed the state of EMF epidemiology with particular reference to how the CCRG distance results relate to existing findings.
see the abstract
Methodology paper
This paper, published in the Journal of Radiological Protection in 2008, gave full details of the exposure-assessment methods used in the distance and magnetic fields papers.
see the abstract
The magnetic-fields results paper
This paper, published in the British Journal of Cancer in 2010, looks at exactly the same subjects (and power lines) as the "distance" paper, but instead of just calculating the distance from the power line, goes further and calculates the magnetic field from the power line.
See:
Results in a nutshell
For childhood leukaemia, there is a relative risk for fields greater than 0.4 µT compared to fields less than 0.1 µT of about 2, which is not statistically significant in itself but is consistent with previous studies. But these magnetic fields are found only really within 50 m or so of these power lines. Therefore magnetic fields seem extremely unlikely to explain the previous "distance" findings, where the elevation in risk extended at least 600 m.
Future work
The CCRG is continuing work on extensions of this study, including:
- including power lines in Scotland as well as England and Wales
- including 132 kV power lines as well as 275 and 400 kV
- looking at underground cables as well as overhead lines
- including more recent cases and controls
- looking at the effect of using alternative controls