Scarfed from http://cam.utmb.edu/resources/aim-essays/MagneticTherapy.doc and reprinted here without permission under the Fair Use Doctrine.
By the 19th Century magnetic therapy was widespread in the United States, and many people view this time as an “electromagnetic era of medical quackery” (1). During this time traveling salesmen and healers sold magnetic salves, liniments, magnetic rings, magnetic insoles, and clothes lined with magnets. These devices were reported as being cures for many ailments with C.J Thatcher, who owned the Chicago Magnetic Company stating, “I can cure anything” (1). During this time a rift was developing between conventional practitioners and promoters of magnetic therapy, so physicians began to study the effects of magnetic field therapy. In the New York Medical Journal in 1892 a paper was published by a physician and his associates who set out to establish the effects that electromagnetic fields had on physiologic processes by exposing frogs, dogs, and humans to powerful electromagnetic fields, and they concluded that exposure to the electromagnetic field did not alter circulatory, cellular, neurologic, or respiratory function. The authors concluded that there was no physiologic basis for electromagnetic therapy.
At the start of the 20th century magnet therapy was considered a justifiable part of medicine, and with the developing field of radiology and radiation therapy it was often practiced in association with radiation treatments. Despite it use in more mainstream medicine there were still devices like the “Dynamizer” and “Oscilloclast,” which were sold with claims of being able to diagnose and treat patients even if they were long distances away (1).
Currently magnet therapy is widely marketed on the internet and on television advertising with magnet sales totaling $500 million annually (3). Most of the companies that advertise make claims that magnet therapy can help to ease pain from arthritis or muscle soreness, but there are also claims of treating migraine headaches, sciatica, preventing cancer, healing diabetic ulcers, increasing T-cell count in HIV patients, improving immunity, increasing bone density, treating allergies etc. (2). Due to these broad based claims, most of which have not been verified by scientific trials, legal action has been brought against many of the companies with several being fined large sums of money and sanctioned to stop making these claims.
Biomagnetic therapy is measured in gauss, which is thought to be the determining factor of the speed at which the magnet works, although its effectiveness is thought to be due to the thickness of the magnet itself (3). Current practitioners suggest that magnets work by attracting the iron in hemoglobin to the site of interest, thereby increasing the blood circulation and oxygen delivered to that area. Despite this claim it has been noted that the use of magnetic pads does not induce the redness and warmth that would be associated with increased blood flow (3). Under the same theory it would also be assumed that using a stronger magnet would produce an even stronger effect, but this has not been the case as demonstrated by patients who receive an MRI, which produces very strong magnetic fields.
Since magnet therapy is widely considered to be safe, many practitioners have been examining its efficacy to treat a variety of conditions. Magnets have been studied as a way of treating pain, arthritis, bone healing, muscle soreness, stress urinary incontinence, depression, seizure therapy, hot flashes, wound healing, and as an aid in diaphragm contraction in ICU patients. Recently the FDA has approved the use of electromagnetic field therapy for the treatment of poorly healing fractures due to its demonstrated ability to stimulate bone growth.
The treatment of pain with magnetic therapy is one of the most widely studied modalities. The main basis for positive claims is from a double-blinded randomized placebo controlled clinical trial done at Baylor College of Medicine in Houston by Valbona et al, which studied the response of post-polio patients with knee pain when exposed to magnets versus sham magnets. They measured pain on the McGill Pain Questionnaire before and after application of either the placebo or 300 to 500 Gauss magnetic devices applied to the affected area for forty-five minutes. They found that patients in the treatment group had a decrease of 4.4 +/- 3.1 (p<.0001) on a 10-point scale as opposed to a decrease of 1.1 +/- 1.6 points (p<.005) in the placebo group. Their conclusion was that in post-polio patients the application of a device delivering a static magnetic field between 300 and 500 gauss resulted in significant and prompt relief of pain in post-polio subjects (5). This study is widely cited by companies that produce and promote magnetic therapy, but there were several problems with the study. One of the problems was that the ratio of women to men in the treatment group was twice that of the control group, so if women are more responsive to placebos then that would lead to improved scores in the treatment. Other problems included the placebo group having an average age of four years older than the treatment group, not measuring the pressure applied to the pain trigger point, and there was only one treatment session with no follow-up with the patients (2). Another study with positive results was a randomized double-blinded placebo controlled trial evaluating magnet therapy in patients with chronic pelvic pain by Brown et al. They selected thirty-two women who were randomized into either a group wearing 500 gauss magnets to abdominal trigger points for 24 hours a day or placebo sham magnets for two weeks, and 19 patients completed four weeks. They found that the treatment group had significantly lower scores following four weeks of treatment using the Pain Disability Index (p<.05), Clinical Global Impressions-Severity (p<.05), and the Clinical Global Impressions-Improvement (p<.01). They concluded that wearing active magnets on abdominal trigger points might reduce chronic pelvic pain when worn continuously. The major problem with this study was that due to the active magnets properties (adheres to metal), the treatment group was more likely to identify their treatment (p<.05), which would significantly impair the placebo effect in the placebo group (7). Several other studies have reported no effect in treating pain with bio-magnetic therapy. A randomized double-blinded placebo controlled trial done by Caselli et al studied the effect on heel pain of magnetic foil placed in PPT/RX Firm Molded Insole versus the Insole without the magnetic foil. The patients wore the insoles for four weeks and the pain was measured before and after using the foot function index. They found that after four weeks approximately 60% of both groups reported improvement, with no significant difference between the two groups. They concluded that the magnetic foil offered no advantage over the plain insole (4). Another randomized double-blinded placebo controlled crossover trial by Collacott et al was designed to study the use of magnets for the treatment of chronic low back pain. Twenty patients with a history of low back pain were treated for two weeks for six hours per day, three days a week with either magnet or placebo for one week, then after a one week hiatus received another week with the opposite treatment. Outcomes were measured with the Visual Analog Scale, Pain Rating Index of the <nop>McGill Pain Questionnaire, and range of motion measurements of the lumbosacral spine. They found no significant differences on any of the outcome variables for the two groups, and they concluded that application of the magnet had no effect on their small group of patients with chronic lower back pain (6). In another randomized double-blinded placebo controlled trial Steizinger et al studied the effects of magnet therapy for the treatment of exercise induced delayed onset muscle soreness. Thirteen subjects were randomized into the 500 gauss magnet or placebo group, then following a treadmill protocol designed to induce soreness, they received treatment for two one hour sessions at twenty-four, forty-eight, and seventy-two hours. The outcomes measured were pain scale, lower leg circumference, thigh circumference, leg volume, and knee extension. The investigators found no significant differences between the two groups, and concluded that magnet therapy did not altar the time course of recovery for exercise induced delayed onset soreness (8,9).
Magnetic stimulation therapy has been studied as a treatment for refractory epilepsy and for the treatment of depression with some positive results. A study by Mirza et al studied the role of a higher magnet current being used in concordance with vagal nerve stimulation in nine patients. They found that magnet settings of 2.75-3.0 mA were found to abort 100% of simple seizures and 98% of grand-mal seizures. They concluded that higher magnet current would be beneficial for patients with poorly controlled secondarily generalized tonic-clonic seizures (13). Another similar study by Kaneko et al found that 1/3 of the patients in their study reported increases in self confidence due to the magnet use, and that 50% of the patients felt like the magnet therapy was effective (12). For the treatment of depression, several recent meta-analysis have demonstrated that transcranial magnetic stimulation and magnetic seizure therapy have both shown anti-depressant properties, but it has not been established which patient population would best benefit from this form of therapy (11).
There are several other magnet treatments that have been less widely studied. In a randomized placebo controlled crossover study by Carpenter et al involving the treatment of hot flashes following breast cancer treatment they found that magnet therapy was no better than placebo for reducing the number of hot flashes (14). In a double blind study by Kinney et al they studied the effects of magnet therapy on wound healing following suction lipectomy and found that magnet therapy does aid wound healing in post lipectomy patients (15,16). In a study by Galloway et al examining the use of extracorporeal magnetic innervation for the treatment of stress urinary incontinence it was found that patients who received the magnetic therapy were found to benefit with less leakage (84% of patients pre-treatment urodynamic testing versus 51% of patients post-treatment), and they concluded that it will be a good alternative for the treatment of stress urinary incontinence due to its benefits and lack of complications (10). In a study by Similowski et al, the use of magnet stimulation of the diaphragm in critically ill patients was examined, and it was found that magnetic stimulation of the phrenic nerve could stimulate stronger contraction of the diaphragm. They concluded that since magnet therapy would be less invasive and easier for the physician that it could be a good alternative in the future for ICU patients (17).
The current evidence for magnet therapy is still very limited. Most of the evidence is either negative or is from very flawed studies. To integrate this therapy into more conventional medicine there would need to be studies that are designed better and demonstrate efficacy for therapy. Other than the current FDA approved use of electromagnetic therapy for poorly healing fractures, there are not any widely agreed upon uses of magnet therapy. The benefits are that there have not been any demonstrated side effects and it could be a very cost effective alternative, but despite thousands of years of use the efficacy of magnet therapy has not truly been demonstrated yet.
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