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Press releases Saturday 4 June 2005
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(1) IS THERE A LINK BETWEEN CHILDHOOD CANCER AND OVERHEAD POWER LINES?
(2) PRESCRIPTION
OF HEROIN IS LESS COSTLY FOR SOCIETY
(1) IS THERE A LINK BETWEEN CHILDHOOD CANCER AND OVERHEAD POWER LINES?
(Childhood cancer in relation
to distance from high voltage power lines in England and Wales: a case-control
study)
http://bmj.com/cgi/content/full/330/7503/1290
(Science commentary: Power
to confuse)
http://bmj.com/cgi/content/full/330/7503/1293
(Editorial: The causes of
childhood leukaemia)
http://bmj.com/cgi/content/full/330/7503/1279
Children living close to high voltage overhead power lines at birth may be at an increased risk of leukaemia, finds a large study in this week’s BMJ.
But the authors emphasise that these results may be due to chance and further research is needed to find out whether there really is a link.
About one child in 2000 develops leukaemia before the age of 15 years.
Although we don’t yet understand its causes, researchers have studied a variety of possible explanations including genetic susceptibility, ionising radiation, unusual patterns of exposure to infection, and electromagnetic fields.
The electric power system produces extremely low frequency electric and magnetic fields, and since 1979 there has been concern that these fields may be associated with cancer. In 2001, the International Agency for Research on Cancer classified extremely low frequency magnetic fields as “possibly carcinogenic” while others, such as the UK Childhood Cancer Study, dispute the risk.
Over 29,000 children with cancer, including 9,700 with leukaemia, were included in the study, the largest of its kind to date. The children were aged 0-14 years and were born in England and Wales between 1962 and 1995. They were compared with a group of control children individually matched for sex, approximate date of birth, and birth registration district. The distance of each child’s home address at birth from the nearest high voltage power line was calculated.
Children who lived within 200m of high voltage power lines at birth appeared to have a 70% raised risk of leukaemia compared with those who lived beyond 600m. There was also a slightly increased risk for those living 200-600m from the lines at birth.
To put these risks into perspective, about five of the 400-420 cases of childhood leukaemia that occur annually in England and Wales may be associated with power lines.
No excess risk was found for other childhood cancers.
The finding that the increased leukaemia risk extends so far from the line is surprising in view of the low average level of exposure to magnetic fields at these distances, say the authors. There is no accepted biological mechanism to explain these results; indeed, the relation may be due to chance or some other factor associated with living near power lines.
In an accompanying editorial, Heather Dickinson from the University of Newcastle upon Tyne agrees that, even if the effect is causal, it could account for only a tiny proportion of cases.
She says, “Magnetic fields from power lines are very weak – only about 1% of the earth’s magnetic field which affects all of us all the time – so it would be surprising if they caused leukaemia. The increased risk closer to power lines may reflect some other factor that varies geographically.” The study didn’t measure the magnetic field from either the power lines or other sources.
“We don’t yet fully understand the aetiology of childhood leukaemia,” she says. “Nevertheless, we are now reasonably sure that it often involves damage to DNA before birth, and an unusual pattern of exposure to infections after birth.
Further insights into the causes of childhood leukaemia will almost certainly come through advancing technology helping us understand the molecular events which drive leukaemic changes,” she concludes.
Contacts:
Paper: Gerald Draper, Honorary Senior
Research Fellow, Childhood Cancer Research Group, University of Oxford, UK
Email: gerald.draper@ccrg.ox.ac.uk
John Swanson, Scientific Adviser, National Grid Transco plc, London, UK
Editorial: Heather Dickinson, Principal
Research Associate, Centre for Health Services Research, University of Newcastle
upon Tyne, UK
Email: heather.dickinson@ncl.ac.uk
(2) PRESCRIPTION OF HEROIN IS LESS COSTLY FOR SOCIETY
(Cost utility analysis of
co-prescribed heroin compared with methadone maintenance treatment in heroin
addicts in two randomised controlled trials)
http://bmj.com/cgi/content/full/330/7503/1297
Prescribing methadone plus heroin to chronic, treatment resistant addicts is less costly than methadone alone because it reduces criminal behaviour, finds a study in this week’s BMJ.
The study involved treatment resistant heroin addicts taking part in methadone maintenance programmes in six cities in the Netherlands. Prior to study entry, the heroin addicts frequently engaged in illegal activities to acquire money or drugs.
They were randomised to treatment with methadone plus heroin (experimental group) or with methadone alone (control group). After one year, data from 430 patients were analysed.
Co-prescription of heroin was associated with better quality of life measures. Although the costs of co-prescription were considerably higher, they were offset by lower costs of law enforcement and reduced costs of crime against property. The average total net savings amounted to €12,793 per patient per year.
From a societal perspective, supervised medical prescription of methadone plus heroin to chronic, treatment resistant addicts is very efficient.
Contact:
Press and Communication Department,
Academic Medical Centre, University of Amsterdam, Netherlands
Email: wetenschapsvoorlichting@amc.uva.nl
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