Responses to the CCRG study of power lines and childhood cancer

For details of the study itself, see here.

Scientific responses to the study are made through BMJ’s "Rapid Responses”, the electronic equivalent of Letters to the Editor.

We provide here links to other comments made about the study by various bodies.
Note: where available we give web links. If the statement is not available on the web we include it at the bottom of this page.

Bristol University

“These latest findings not only strengthen further the evidence that children living in proximity to high voltage powerlines are at increased risk of childhood leukaemia, but in finding effects up to 600 metres away they invoke electric field corona ion effects as a possible causal mechanism”
full statement

Cancer Research UK

“These results may indeed be entirely due to chance. What this paper does not show is that power lines directly cause childhood leukaemia…. People who currently live or have lived near power lines in the past need not panic about this research.”
full statement

Children with Leukaemia

“The proportion of the UK population at increased risk of childhood leukaemia from proximity to high voltage overhead power lines is ten times greater than previously demonstrated.
… Planning controls must be introduced to stop houses and schools being built close to high voltage overhead power lines.”
full statement

Coghill Research Laboratories

“The Draper et al study of childhood cancers near powerlines, whose publication in BMJ was delayed for two years, funded by the UK Dept of Health and the UK power utility NGT, announced a near doubling of childhood leukaemia among populations living close to high voltage powerlines. The major impact on health however is thought by many scientists to be the electromagnetic fields (EMF) from domestic electric appliances, which was not addressed by this costly national study.”
full statement

Energy Networks Association

“The electricity industry welcomes this study. As a responsible industry we are completely committed to the safety of the public and our staff. We are proud that we have been involved in instigating and carrying out this study. …The study strengthens the evidence that childhood leukaemia rates are slightly higher near power lines, but leaves the question of what causes this more confused than before.”
full statement

Health Protection Agency

“By virtue of the longer time period covered, the new study provides more precise information on childhood cancer rates in the proximity of high-voltage power lines than does the UK Childhood Cancer Study. However, the absence of field measurements in homes and the lack of information on potential confounders make it difficult to know whether the raised risks reported for leukaemia represent a direct effect of electromagnetic field exposure.“
full statement

Institution of Electrical Engineers

“The IEE is of the view that this new data makes it highly unlikely that the elevated rates are due to magnetic fields from the lines. It is more likely to be caused by some characteristic of the areas that the power lines pass through, or of the people who live near them … The IEE considers that the study points away from magnetic fields from power lines as a cause of childhood leukaemia, and hence attention should focus on investigating other possible causes of this disease.”
full statement

Leukaemia Research Fund

“[The previous UKCCS study] has reported that there is minimal risk of childhood cancer in the UK from either proximity to electrical installations or the magnetic field levels they produce…. The Draper paper does not include information on magnetic field levels or distance from low-voltage lines and cables. … The authors also comment - and Leukaemia Research shares the view – that there is no reason why anyone should be advised to move house on the basis of these new results."
full statement

Revolt

“The study finds statistically significant results of two kinds. First there are stronger results for birth addresses within 200 metres of a power line. Second there are weaker results in the range 200 - 600 metres, which on close inspection show statistical quirks and are likely to be spurious. The authors recognise the statistical weakness but do not point out the quirks…. The results within 200 metres are consistent with and broadly reinforce the established data doubling the risk of childhood leukaemia for children exposed prior to diagnosis above 0.4 microTesla…. The results in the range 200 - 600 metres are likely to be spurious. They should not be relied on to support or deny an effect at 600 metres…”
full statement

Media coverage

For a sample of the media coverage, see:

BBC News

The Guardian

The following three statements do not appear on the web so we include the full text here:

University of Bristol

STUDY OF CHILDHOOD LEUKAEMIA NEAR POWERLINES PUBLISHED IN THE BRITISH MEDICAL JOURNAL

‘Findings of higher childhood leukaemia up to 600 metres from powerlines greatly extends findings from previous international studies, including those in the UK’, says Bristol Professor

The findings by Dr Gerald Draper and colleagues of increased rates of childhood leukaemia up to 600 metres from high voltage powerlines in the UK, published in the British Medical Journal today, greatly extends previous findings from a pooled analysis of international studies which included the results of a previous UK study.

Denis Henshaw, Professor of Human Radiation Effects at the University of Bristol said today:

“These latest findings not only strengthen further the evidence that children living in proximity to high voltage powerlines are at increased risk of childhood leukaemia, but in finding effects up to 600 metres away they invoke electric field corona ion effects as a possible causal mechanism. The fact that this study has looked at the birth address is particularly important because the initial damage that may lead to leukaemia is thought to occur in-utero.”

While the number of excess cases of the disease in children living near powerlines may be around 5 per year, this may be the tip of the iceberg: (i) in terms of the extent to which both the magnetic fields and electric fields associated with the electricity supply may be a factor in the incidence of childhood leukaemia, and (ii) in terms of the many other illnesses also associated with magnetic fields such as adult leukaemia, adult brain cancer, miscarriage and depression”.

A particularly important finding from Dr Draper’s work is the increase in childhood leukaemia up to 600 metres from powerlines, well beyond the range of powerline magnetic fields. In order to understand this finding we need to consider the separate effects of the magnetic fields and electric fields associated with powerlines.

For the magnetic fields, studies in human populations have shown that such fields are capable of disrupting the night-time production of the important hormone melatonin in the pineal gland. Melatonin is a particularly powerful antioxidant which acts as a natural anti-cancer agent in the body. Studies have shown the hormone to be highly protective of oxidative damage to human blood cells - the sort of damage that could lead to leukaemia.

However, powerline electric fields act differently. The intense electric field on the surface of powerline cables is sufficient to ionise the air, producing so-called corona ions. This process is the cause of the characteristic buzzing or crackling of powerlines. Corona ions are small electrically-charged particles which, when emitted from powerlines attach themselves to particles of air pollution, making these particles more likely to be trapped in the lung when inhaled. In this way people living near powerlines may be exposed to increased levels of air pollution. Crucially, corona ions can be carried several hundred metres from powerlines by the wind, so effects may be felt much further away than for magnetic fields.

Professor Henshaw said:

“In principle, corona ion effects could well explain the profile of increased incidence of childhood leukaemia up to 600 metres from powerlines”.

More information on the research in Professor Henshaw’s team may be found on their website: http://www.electric-fields.bris.ac.uk. The work of Professor Henshaw’s team is funded by CHILDREN with LEUKAEMIA, Britain’s largest charity devoted to understanding the causes and prevention of childhood leukaemia.

Notes for Editors

1. Corona ions

Corona ions are routinely emitted from high voltage powerlines, especially in wet conditions outdoors. In the 1950s, corona ions effects were measured up to 7 kilometres from powerlines both in the UK and in Germany. In today’s conditions, we have measured corona ions up to 7 kilometres from a high voltage powerline near Glastonbury, Somerset. We have previously estimated that on average corona ion effects, significant to adversely affect human health, extend to 400 metres from powerlines. In this regard, the findings by Dr Draper of increased childhood leukaemia up to 600 m from powerlines in clearly significant.

Principal publications:

· Fews, A.P., Henshaw, D.L., Wilding, R.J. and Keitch, P.A. Corona ions from powerlines and increased exposure to pollutant aerosols. International Journal of Radiation Biology, 75(12), 1523-1531, (1999). – technical report of corona ion emission from high voltage powerlines in the UK

· Henshaw, D. L., 2002. Does our electricity distribution system pose a serious risk to public health? Medical Hypotheses, 59(1), 39-51 - see discussion of corona ions on pages 43 - 46.

· Fews, A. P., Wilding, R. J., Keitch, P. A., Holden, N. K. and Henshaw, D. L., 2002. Modification of atmospheric DC fields by space charge from high-voltage power lines. Atmospheric Research, 63, 271-289 - further detailed technical report of corona ion emission from high voltage powerlines in the UK

· National Radiological Protection Board (NRPB, 2004). Particle Deposition in the Vicinity of Power Lines and Possible Effects on Health Documents of the NRPB, 15, No. 1. Chilton, UK. HMSO, London ISBN 0-85951-531-1. – NRPB (now HPA) report on corona ions

2. Other background information

In Autumn 2000, a pooled analysis of international studies on electric and magnetic fields (EMFs) and childhood leukaemia, led by Professor Ahlbom of the Karolinska Institute in Sweden, which included the results of a study in the UK, was published in the British Journal of Cancer in 2000 (Vol. 83, pp 692-698). The study showed that children exposed to magnetic fields above a level of 0.4 microtesla were at twice the risk of contracting the disease. While this level of exposure is above average levels found in the home, it is well below levels found near high voltage powerlines where values can reach several microtesla or even tens of microtesla. The Ahlbom study has since led the International Agency for Research on Cancer (IARC) to classify magnetic fields as a possible carcinogen and the World Health Organisation to call an international meeting to discuss the issue of introducing precautionary measures against exposure to EMFs associated with the electricity supply. Last year, the then Public Health Minister, Melanie Johnson, set up a Stakeholder Advisory Group on EMFs (SAGE) to examine the issue of precaution against EMF exposures in the UK.

The International Agency for Research on Cancer (IARC) Report on magnetic fields was published in: IARC Monographs of the Evaluation of Carcinogenic Risks to Humans, 2002. Non-Ionizing Radiation, Part 1: Static and Extremely Low-Frequency (ELF) Electric and Magnetic Fields. Volume 80, 19-26 June 2001, IARC Press, 150 Cours Albert Thomas, F-69372 Lyon Cedex 08, France.

In June 2002, a major report on EMF health effects from the California Health Department found increased risk of childhood leukaemia, adult leukaemia, adult brain cancer and miscarriage. This report may be accessed at:
http://www.dhs.ca.gov/ehib/emf/RiskEvaluation/riskeval.html

Childhood leukaemia is a mercifully rare disease, which constitutes about one third of approximately 1400 cases of childhood cancer per year. The number of cases associated specifically with powerlines is small in absolute terms but the number associated with the electricity supply generally is not known. Childhood leukaemia is a biologically diverse disease and is likely to arise by several aetiological pathways. A number of factors are associated with the disease, such as infections, background radiation, magnetic fields, air pollution and paternal pre-conceptual exposure to hydrocarbons.

Cancer Research UK

Comment on the BMJ paper "Childhood cancer in relation to distance from high voltage power lines in England and Wales:a case control study."
Professor John Toy, Cancer Research UK's Medical Director, says:

"This study reports a very slight increase in the risk of childhood leukaemia for children born near power lines, but the researchers could not link this to the power lines themselves. These results may indeed be entirely due to chance. What this paper does not show is that power lines directly cause childhood leukaemia. This may seem confusing, but there may be other more common factors that exist in these areas that contribute to the apparent increased risk."

"The numbers of cases are small. This apparent very slight increase in risk would, if real, equate to five extra cases of childhood leukaemia in a total of around 400 that occur in a year."

"People who currently live or have lived near power lines in the past need not panic about this research. The triggers that cause childhood leukaemia are most likely a random course of events over which a parent has no control."

Children with Leukaemia

Response from leading UK charity CHILDREN with LEUKAEMIA to BMJ editorial/article on the causes of childhood leukaemia

The proportion of the UK population at increased risk of childhood leukaemia from proximity to high voltage overhead power lines is ten times greater than previously demonstrated.

Eddie O’Gorman, Chairman of leading UK charity CHILDREN with LEUKAEMIA, who has himself lost a child to leukaemia, said “We have to do everything we can to protect young lives: there is now a clear case for immediate government action. Planning controls must be introduced to stop houses and schools being built close to high voltage overhead power lines.”

Notes to Editors

Ten fold increase in demonstrated cases: previous studies have shown similar increases in childhood leukaemia but only in the less than 0.5% of the population living closest to high voltage overhead power lines. This study shows an apparent impact affecting close to 5% of the UK population.

CHILDREN with LEUKAEMIA is Britain’s leading charity dedicated exclusively to the conquest of childhood leukaemia through pioneering research, new treatment and support of leukaemic children and their families.

Leukaemia is Britain’s biggest child-killer disease and is on the increase.

CHILDREN with LEUKAEMIA currently invest in excess of £10m every year in its vital charitable work including research, support and education. Last month CHILDREN with LEUKAEMIA committed over £1m in grants for research into the causes of childhood leukaemia with 12 projects examining the importance of factors such as diet, melatonin, infection, genetic susceptibility and exposure of EMFs and radiation.

In 2004 CHILDREN with LEUKAEMIA organised the world’s first international conference on the causes and prevention of childhood leukaemia which attracted 250 scientists and clinicians. CHILDREN with LEUKAEMIA is in the mainstream of international opinion in believing that childhood leukaemia is a multi-causal and multi-factorial disease.

CHILDREN with LEUKAEMIA is a key partner with the Department of Health and National Grid Transco in SAGE (Stakeholder Advisory Group on EMFs) which is examining the health effects of EMFs and the charity is contributing 1/3 of the costs. SAGE was approved by Health Minister, Melanie Johnson, and is expected to be re-approved by the new Public Health Minister, Caroline Flint. The purpose of SAGE is “To bring together the range of stakeholders to identify and explore the implications for a precautionary approach to ELF EMF (electric and magnetic fields) and make practical recommendations for precautionary measures”

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