Power lines and leukemia risk

According to a recent UK study, babies who live near high-voltage power lines are almost twice as likely as others to develop leukemia during childhood.

However, despite detailed analysis of more than 9000 childhood cases of leukemia over three decades, the Oxford University scientists who led the research say there is still insufficient evidence to establish with any certainty whether the magnetic fields around the cables actually cause some cases of the cancer.

Gerald Draper, Honorary Senior Research Fellow at the university's Childhood Cancer Research Group, identified the birth records of children born between 1962 and 1995 who later developed cancer, and mapped the addresses listed on the children's birth certificates against the national electricity grid in England and Wales.

The same was done for a control group of children who did not have cancer - each matched to one of the cancer patients for date of birth, sex and birth registration district.

Draper found the 9700 children with leukemia - the most common childhood cancer - were 70% more likely than the others to have lived within 200 metres of a high voltage power line.

The link grew weaker the further away from power lines children lived.

Among the 20,000 children who developed cancers other than leukemia, there was no extra likelihood of having lived near overhead cables.

Magnetic fields from power lines were "the most obvious explanation". But at a distance of 200 metres, these forces were typically lower than other sources of magnetism within the home such as household electrical wiring and appliances, he said.

"We have no satisfactory explanation for our results in terms of causation, and the findings are not supported by convincing laboratory data or any accepted biological mechanism," Dr Draper wrote in the British Medical Journal.