Leukemia and lymphoma incidence in rodents exposed to low-frequency magnetic fields

A weak association between residential or occupational exposure to electric and magnetic fields (50/60 Hz fields) and an increased incidence of leukem ia has been reported, Numerous animal studies have evaluated the potential association between magnetic-field exposure and leukemia. These include lon g-term (up to 2% years);bioassays, initiation/promotion studies, investigat ions in transgenic models, and tumor growth studies, Exposure to 60 Nz circ ularly polarized magnetic fields at 1,400 mu T for 28 months did not affect lymphoma incidence in mice, The study included over 2000 C57BL/6J mice. In another study, 1000 B6C3F(1), mice exposed to 60 Hz magnetic fields up to 1000 mu T for 2 years showed no increase in lymphomas, Approximately 400 tr ansgenic E mu-Pim1 mice exposed to 50 Hz fields up to 1000 mu T for up to 1 8 months had no increased incidence of leukemia. Similarly, Tup53(+/-) mice and Pim1 transgenic mice exposed to 60 Hz magnetic fields for 23 weeks sho wed no increased incidence of lymphoma. Three studies in F344 rats exposed to 50 or 60 Hz magnetic fields up to 5 mT showed no increased incidence of leukemia, The combined animal bioassay results are nearly uniformly negativ e for magnetic-field exposures enhancing leukemia and weaken the possible e pidemiological association between magnetic-field exposures and leukemia in humans as suggested by epidemiological data, (C) 2000 by Radiation Researc h Society.