Exposure to extremely low frequency magnetic fields among primary school children in Spain
- A Tardón1,
- H Velarde1,
- P Rodriguez2,
- S Moreno3,
- M Raton3,
- J Muñoz4,
- A R Fidalgo2,
- M Kogevinas3
- 1Instituto Universitario de Oncología-Obra Social Cajastur, University of Oviedo, Spain
- 2Oviedo Municipal Health Department
- 3Institut Municipal d'Investigació Médica, Barcelona, Spain
- 4Universitat Autónoma de Barcelona, Spain
- Correspondence to: Dr M Kogevinas, Environmental and Respiratory Health Research Unit, Municipal Institute of Medical Research (IMIM), 80 Dr Aiguader Road, Barcelona 08003, Spain; kogevinas{at}imim.es
- Accepted 15 November 2001
Epidemiological studies have found an increased leukaemia risk in children with high residential exposure to extremely low frequency electromagnetic fields (ELF-EMF). Two recent independent reanalyses of published epidemiological studies1,2 found statistically significant increased risks in children with average residential exposures equal or above 0.3 or 0.4 μT (micro teslas, the unit of measurement of magnetic field density). An IARC working group (June 2001) evaluated that these findings were unlikely to be attributable to chance, but could be affected by selection bias. Therefore this association between childhood leukaemia and high residential magnetic field strengths was judged limited evidence for excess cancer risk in exposed humans.
Exposure at school could significantly contribute to children's overall exposure, but only few epidemiological studies incorporated such measurement.3–5 We evaluated level of exposure to ELF-EMF in primary schools in the city of Oviedo and the province of Barcelona, the second region being one of the most industrialised areas of Spain.
METHODS
This is a descriptive study of environmental exposures in schools with an ecological comparison within areas. All primary schools (n=43) in Oviedo (Asturias) were contacted (participation rate 100%). In the Province of Barcelona, 75 of a total of 887 registered schools were selected through a two stage random stratified weighted sampling. To select the number of schools to be …
