30 Jul 2007

Radio towers linked to leukaemia

Children who live close to an AM radio transmission tower may have an elevated risk of leukaemia, a study suggests.

South Korean researchers found that children who lived within 2 kilometres (about 1-1/4 miles) of an AM radio transmitter were twice as likely to develop lymphocytic leukaemia as children who lived more than 20 kilometres (approximately 12-1/2 miles) away.

There was no such link found for childhood brain cancer or any cancer in babies, according to the researchers, led by Dr Mina Ha of Dankook University College of Medicine.

The findings, published in the American Journal of Epidemiology, add to the conflicting body of research on electromagnetic fields (EMFs) and cancer. EMFs are emitted by a wide variety of sources, like home appliances, cell phones, power lines and radio and TV transmission towers.

Mixed findings
Researchers have found limited evidence that living close to power lines might be a risk factor for childhood leukaemia. Studies on the possible health risks of radio and TV towers have produced mixed findings, according to Ha's team.

For their study, the researchers attempted to get a more accurate assessment of the relationship between children's exposure to radio wave energy and their risks of leukaemia and brain cancer - the two most common childhood cancers.

The researchers took measurements of the electric and magnetic fields surrounding AM transmission towers in various areas of South Korea, and used a mathematical model to estimate nearby residents' exposure to radiation from the towers.

The study included 1 928 children with leukaemia, 956 with brain cancer and 3 082 healthy children. Ha's team found that children who lived less than two miles from a radio tower were twice as likely to have lymphocytic leukaemia than those who lived more than a dozen miles away.

Up to 59% increased risk
Similarly, when the researchers looked at estimated exposure to radiation from the towers, children with the least exposure had the lowest leukaemia risk. The risk was 39 percent higher for those with intermediate exposure, and 59 percent greater for those with the highest exposure.

The results, Ha's team concludes, "suggest a possible carcinogenic effect" of energy from AM radio towers. However, they say more research is needed to confirm the findings, and to figure out the biological mechanisms that may be at work.

SOURCE: American Journal of Epidemiology, August 1, 2007. – (Reuters Health)