Researchers at the University of Toronto and the Hospital for Sick Children have found an association between magnetic field exposures in residences and the risk of developing childhood leukemia.
The study, reported in two separate papers in the current issues of the International Journal of Cancer (IJC) and the journal Cancer Causes and Control (CCC), shows that children with higher exposures to magnetic fields in residences are two to four times more likely to develop leukemia compared to children who are less exposed. The study comprehensively measured magnetic field exposures inside and outside the children's homes. Wire code was also assigned to each residence. For some children, EMF exposures were measured by a personal monitor.
The authors report in IJC that overall, wire code -- a surrogate indicator of magnetic field exposure based on the physical characteristics of the line and proximity of the residence to power lines -- was not associated with an increased risk of developing leukemia. However, leukemia risk was elevated for children diagnosed at less than six years of age in relation to magnetic field exposures in residences occupied during the first two years of life.
A subset of the total study population wore a personal monitoring device which measured EMF during usual activities in the home over 48 hours. As reported in CCC, exposure to magnetic fields was associated with a two-fold increase in risk of developing leukemia.
When other factors such as residential mobility, power consumption, child's medical history and other environmental exposures were taken into account, children exposed to higher levels of magnetic fields were 4.5 times more likely to develop leukemia compared to less exposed children. Risks were higher for children diagnosed at less than six years of age and for those with acute lymphoblastic leukemia -- the most common type of leukemia in children.