Leukemia Risk High Near Power Lines
Children born close to high-voltage overhead power lines are more likely to be diagnosed with leukemia, according to the results of a major Government-funded study published today. Researchers find that those whose childhood homes are within 200 meters of a power line have an almost 70 per cent greater risk of being diagnosed with leukemia. However, they stress that they have not established the cause of the increased risk and that it could be due to other factors, such as differences in wealth between those who live near power lines and those who do not.
They say that if the 275 kilovolt (kV) and 400kV national grid lines investigated in the study are indeed the cause of the rise, they would be responsible for approximately one per cent of leukemia cases in England and Wales, or around five cases per year. Campaigners claim that lower voltage regional power lines, which operate at 132kV, might have the same effect, in which case the number of leukemia cases linked to electricity transmission could be 10 times higher.
The study, the largest of its kind to date, is published today in the British Medical Journal. It analyses 29,081 people from England and Wales who were diagnosed with cancer aged under 15 between 1962 and 1995. They are compared with the same number of healthy individuals, matched for sex and year and area of birth. Researchers calculated the distance from each person's home at birth and the nearest high-voltage overhead line.
For those born within 200 meters of a power line, the risk of leukemia is 69 per cent greater than for those born more than 600 meters away. Those between 200 meters and 600 meters from a power line are 23 per cent more likely to have been diagnosed with leukemia than those whose homes were more than 600 meters away. No increased risks are found for other types of childhood cancer. Dr Gerald Draper, of the Oxford Childhood Cancer Research Group, led the research. He says: "The increased risk of leukemia up to 600 meters from the high voltage power was surprising in the view of the very low level of magnetic fields at these distances.
"There is no accepted biological mechanism to explain these results. It could be down to confounding factors such as socioeconomic factors.
"People should not panic. More research must be carried out to find the mechanism."
DR John Swanson, a scientific adviser to National Grid Transco and one of the study's co-authors, says: "The study strengthens the evidence that childhood leukemia rates are slightly higher near power lines, but leaves the question of what causes this more confused than before." One theory is that "corona ions", small charged particles given off by power lines, attach themselves to air pollution particles. It is argued that those who live nearby are therefore more at risk from inhaled pollution.
Around 400 to 420 new leukemia cases are diagnosed in England and Wales each year. Scientists have suggested a range of causes including genetic susceptibility, ionizing radiation, unusual patterns of exposure to infection and electromagnetic fields. Two major studies published in 2000 by Swedish and American researchers concluded that there was a doubling of the risk of childhood leukemia associated with the level of magnetic field exposure received around 100 meters from a power line.
Alasdair Phillips, of the consumer group Powerwatch, said: "The Government should bring in a ban on new building within 250 meters of high voltage power lines. "Nurseries and schools, or the adjacent power lines, should be relocated so that they are further away than 500 meters from high voltage overhead power lines."
Copyright of Telegraph Group Limited 2005.