Childhood leukaemia close to high-voltage power lines - the Geocap study, 2002-2007

Background: High-voltage overhead power lines (HVOLs) are a source of extremely low-frequency magnetic fields (ELF-MFs), which are classified as possible risk factors for childhood acute leukaemia (AL). The study was carried out to test the hypothesis of an increased AL incidence in children living close to HVOL of 225–400kV (VHV-HVOL) and 63–150kV (HV-HVOL). Methods: The nationwide Geocap study included all the 2779 cases of childhood AL diagnosed in France over 2002–2007 and 30000 contemporaneous population controls. The addresses at the time of inclusion were geocoded and precisely located around the whole HVOL network. Results: Increased odds ratios (ORs) were observed for AL occurrence and living within 50m of a VHV-HVOL (OR ¼1.7 (0.9–3.6)). In contrast, there was no association with living beyond that distance from a VHV-HVOL or within 50m of a HV-HVOL. Conclusion: The present study, free from any participation bias, supports the previous international findings of an increase in AL incidence close to VHV-HVOL. In order to investigate for a potential role of ELF-MF in the results, ELF-MF at the residences close to HVOL are to be estimated, using models based on the annual current loads and local characteristics of the lines. High-voltage overhead power lines (HVOLs) are one of the major sources of extremely low-frequency magnetic fields (ELF-MFs), considered a possible risk factor for childhood leukaemia. In the absence of any underlying biological hypothesis, the International Agency for Research on Cancer (IARC) classified ELF-MF as possible carcinogens (group 2B), based on epidemiological observations over more than two decades (IARC, 2002). The first meta-analyses concluded that exposure to ELF-MF levels of at least 0.3mT was significantly associated with an increased incidence of childhood acute leukaemia (AL) (odds ratio (OR) ¼ 1.7 (1.2–2.3)