electromagnetic fields from power lines and appliances do not affect the risk of leukaemia in children, say researchers at the us National Cancer Institute ( nci ) and the University of Minnesota, usa. The study is one of the most comprehensive probes into the links between electromagnetic fields and the risks of developing leukaemia, and may help in resolving the controversy that surrounds it. "We basically found nothing,' says co-author Leslie Robison, a cancer researcher at the University of Minnesota School of Medicine.

According to experts, earlier probes had found conflicting evidence over the existence of such risks. These probes were often small in terms of the number of people and geographic areas scrutinised. Critics say earlier studies often relied on crude or indirect measurements of magnetic fields. The findings of those studies were skewed because the authors made statistical comparisons to their own data and emphasised only those comparisons that showed a cancer risk.

The new report, however, had been designed so that the flaw found in previous studies could be eliminated. The nci study included 638 leukaemia cases from nine states in the us and also involved 520 healthy children. The researchers measured electromagnetic-field levels in several rooms of the children's current and former homes. They took measurements of the rooms where the children's mothers had lived during their pregnancies. All the major tests in the study proved negative. The findings come close on the heels of a recent review by experts at the us National Academy of Sciences that found little evidence about the connection between electricity and cancer.

"The new study should lay the controversy to rest,' says Edward Campion, the deputy editor of the New England Journal of Medicine . According to him, it is time to stop spending money on such studies. Researchers must start investigating the actual causes of leukaemia, he adds.