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Childhood Leukemia and Extremely Low-Frequency
Magnetic Fields: Critical EvaluationofEpidemiologic
Evidence Using Hill’s Framework
Leeka Kheifets and John Swanson
Introduction
The rst study linking extremely low-frequency magnetic elds (ELF-MFs) to childhood
cancer was published in 1979 and has been followed by many other studies. The
International Agency for Research on Cancer (IARC) and the World Health Organization
(WHO) have classied MFs as “possibly carcinogenic to humans,” or as a Group 2B car-
cinogen; this classication was mostly based on consistent epidemiological evidence of an
association between exposure to these elds and ...