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MEDICAL BIOLOGY: NO BENEFITS FROM STATIC MAGNETS

The following points are made by M.H. Winemiller et al (J. Am. Med. Assoc. 2003 290:1474):

1) The use of magnetic fields for pain relief has increased dramatically in the past decade. Despite a paucity of scientific evidence and lack of approval by the US Food and Drug Administration, a large number of people use magnets to relieve their pain. An estimated $5 billion has been spent worldwide on magnetic devices purchased to treat pain,(1,2) with annual US sales estimated at $500 million.(3) The vast majority of devices available to and used by the general public are static magnets, with magnetic fields typically ranging from 200 to 2500 G. Such magnets are generally considered safe when applied to the skin and have few adverse effects.(4-5) The physiologic effects of static magnets on pain, however, are largely unknown. Although some studies have found that bipolar magnets can relieve various sources of pain, all had significant methodological flaws. Several other investigations have failed to show additional benefit from static magnets.

2) Plantar heel pain, commonly referred to as plantar fasciitis, is a common condition among athletes as well as the general population. The characteristic complaints are knife-like pain at the calcaneal insertion of the medial plantar fascia, typically worse on first arising in the morning, and often lasting months to years. Many treatment regimens exist but effectiveness is variable. Insole materials have generally been found to be effective in relieving signs and symptoms.

3) The authors report a randomized, double-blind, placebo-controlled trial to assess the effectiveness of bipolar static magnets in insoles for treatment of plantar heel pain. Cushioned insoles, with either active bipolar magnets or sham magnets, which were worn daily by the participants for 8 weeks.

4) From their results, the authors conclude: Static bipolar magnets embedded in cushioned shoe insoles do not provide additional benefit for subjective plantar heel pain reduction when compared with nonmagnetic insoles.

References (abridged):

1. Weintraub M. Magnetotherapy: a new intervention? Arch Phys Med Rehabil. 1998;79:469-470

2. Eisenberg DM, Kessler RC, Foster C, et al. Unconventional medicine in the United States: prevalence, costs, and patterns of use. N Engl J Med. 1993;328:246-252

3. Rosch P. Stress, pain, fatigue, depression—and magnets. Stress Med. 1998;14:69-74

4. Finegold L. Magnet therapy. Sci Rev Alternative Med. 1999;3:26-31

5. Repacholi MH, Greenebaum B. Interaction of static and extremely low frequency electric and magnetic fields with living systems: health effects and research needs. Bioelectromagnetics. 1999;20:133-160

J. Am. Med. Assoc. http://www.jama.com

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