Children may face twice the risk of getting leukemia if they live near power lines, frequently use hair dryers or watch black-and-white television, says a study sponsored by electric utilities.
The findings offer "considerable support for a relationship between children's electrical appliance use and leukemia risk," said a summary of the study by the University of Southern California.Yet, in a seemingly contradictory finding, the unpublished, preliminary study found no link between the children's risk of getting the blood cancer and the actual electrical fields measured in their bedrooms.
The researchers found slight increases in leukemia risk were associated with exposure to magnetic fields in the bedroom and to children's use of curling irons and electric blankets. But those correlations weren't statistically significant.
The University of Southern California study of 464 Los Angeles County children age 10 and younger is considered important because it was financed by the Electric Power Research Institute.
The utility organization in Palo Alto has been skeptical of earlier studies linking cancer to electromagnetic fields.
The study will "raise general national concern about the role of electric and magnetic fields in causing cancer," Dr. David Carpenter, dean of public health at State University of New York in Albany, said in Friday's Los Angeles Times.
The institute, however, said no single study can settle the controversy over electrical and magnetic fields, which are emitted by every wire and device that carries current.
Dr. John Peters, director of USC's occupational health division, outlined his team's preliminary findings Thursday during a closed-door scientific meeting in Carmel.
The university issued a statement saying the scientists would refuse to discuss the results until they are reviewed by other researchers and published in a scientific journal in about four months.
But in an unusual step, the institute released two summaries of Peters' findings. One was on USC letterhead, the other written by the institute.
Half the children in Peters' study developed leukemia between 1980 and 1987. They were compared with a similar group of children without leukemia. Their parents were interviewed and scientists measured household electromagnetic fields.
The study found children who lived closest to power lines were up to 2 1/2 times more likely to suffer leukemia, consistent with earlier studies conducted in Colorado.
However, the risk was still low: The rate of leukemia was 2 1/2 cases per 20,000 children among those living near power lines, compared with the natural rate of one leukemia case per 20,000 children.
Frequent use of hair dryers and black-and-white televisions also increased leukemia risk. The summaries didn't say by how much. A source quoted by the San Francisco Chronicle said the risk was about doubled.