Lead author Nick Day, PhD, professor of epidemiology at Cambridge University, and colleagues studied 2,226 children in the United Kingdom from infancy to age 14 with a confirmed cancer. Those children were compared with a control group of cancer-free children matched for date of birth and sex.

The researchers took measurements of EMF exposures at the children’s homes – including the proximity and type of overhead power lines nearby and electrical appliances in the homes. They also measured exposures at schools or other institutions attended by the children.

"We find no evidence that magnetic fields associated with the electricity supply increase risk of childhood leukemia, malignant brain tumors, or any other childhood cancer," the study authors wrote.

They added, "The degrees of exposure were low compared with other studies reported from North America, probably because of differences in the operating characteristics of the electricity supply and wiring practices. Our results are consistent with those of larger studies on childhood leukemia that used measured fields and population based studies… ."

The researchers said an overview of all available data from studies of childhood leukemia with measured exposures to EMF is underway.

Michael Thun, MD, vice president of epidemiology and surveillance research for the American Cancer Society (ACS), said the new study is a strong one. "This is really a very nice, large, population-based study. It found no evidence of an association of EMF and acute lymphoclastic leukemia, all leukemias, central nervous system tumors, and all other malignant disease."

Studying the relationship of EMF to cancer is extraordinarily difficult, partly because it is difficult to measure exposures, Dr. Thun said. "This study went to great lengths to capture the major sources of exposure," he added.

The study's findings parallel those of a 1997 study that found no relationship to EMF and the most common types of childhood leukemia, according to Dr. Thun.

However, an editorial accompanying the study points out that there were not enough children with high category exposures to assess their risk reliably. A major childhood leukemia study currently underway in Japan is expected to address this issue.

Cancers in children account for only one in 360, or 0.3 percent, of all cancers. Every year, about 130 new childhood cancers are diagnosed for every 1 million children. However, cancer is the second leading cause of death in children under 14 years of age.