PEMF For Management of Osteoporosis
Abstract: What is osteoporosis?
Osteoporosis is a condition resulting in an increased risk of skeletal fractures due to a reduction in the volume of bone tissue. It has been defined more explicitly as a disease characterized by low bone mass,
microarchitectectural deterioration of bone tissue leading to increased bone fragility and consequential increase in fracture risk.
Pulsed electromagnetic fields (PEMFs) stimulation has been in clinical use for over thirty years for patients with delayed fracture healing and non-unions.
Based upon multicenter, randomized and prospective clinical studies, the Food and Drug Administration, USA, approved PEMF as safe and effective method for treating nonunions and for osteoporosis therapy. Exogenously applied electromagnetic fields (EMF) affect bone metabolism, both in vivo and in vitro. It can improve bone mineral density (BMD) and biomechanical properties and decelerate the bone resorption process in vivo.
While in vitro it can enhance osteoblast activity but cause significant reduction in osteoclast formation, activity and survival shifting the balance towards osteogenesis by affecting both pathways of bone metabolism. This review of the advances in the therapy for osteoporosis will briefly discuss the effect of PEMFs on chronic bony pain, bone mineral density, bone strength and biochemical markers of bone metabolism in the patients with osteoporosis.
Effect of PEMFs on primary osteoporosis
Effect of PEMFs on chronic bony pain of patients with primary osteoporosis
Chronic bony pain is the most common symptom and cause of medical treatment in patients with primary osteoporosis which affects people’s quality of life. Therefore, many studies had concentrated in the analgesic effect of low-frequency pulsed electromagnetic fields.
Several observations and randomized controlled trials demonstrated that most patients with primary osteoporosis can get pain alleviation after 30–60 days treatment of PEMFs. This effect can even appear after therapy for two or three days and is significantly correlated with the number of therapies. One study that consisted of 126 subjects found that patients with type I osteoporosis got better effects than those with type II. Furthermore, PEMFs can significantly ease the pain in osteoporosis patients without joints degeneration; especially in the 40–60-year-old female patients with type I osteoporosis. And the pain of patients with type II osteoporosis, who were more than 70 years old and suffered from hyperostosis, was relieved slowly and may require more than ten treatments to reduce the general chronic pain. Another observation confirmed that PEMFs can not only ease chronic bony pain, but also lighten leg cramps, improve symptoms of insomnia or bad sleep, lower blood pressure, reduce the numbers ofnocturia and eliminate edema in the lower extremities.
It is well accepted that PEMFs effectively relieves chronic bony pain without any side-effects after treatment of 40 minutes five times a week. The frequency of PEMFs was often below 50 Hz and the magnetic field intensity was different in each study but not more than 20 mT. Although the therapeutic parameters were not the same, the pain relief effect of PEMFs on primary osteoporosis was similar.
Nevertheless, these results were not the best evidences because that fewer randomized controlled trials or multicenter studies were included and are meant only as recommendations of the clinical application of PEMFs for osteoporosis. Otherwise, the evaluation standard of pain relief were different, only one study applied the Visual Analogue Scale (VAS), which is a quantitative pain evaluation, the others used a qualitative evaluation.
No study reported a blinded assessment which is recommended for pain relief evaluation. Further strict studies are needed to verify the pain relief effect of PEMFs.
Effect of PEMFs on bone mineral density of patients with primary osteoporosis
Bone mineral density is the gold standard for diagnosing osteoporosis and the best quantitative indicator for forecasting the risk of osteoporotic fracture, monitoring the natural course of osteoporosis and evaluating the effect of pharmacological intervention.
Many studies at home and abroad have been concerned with altering BMD by treatment of PEMFs for patients with osteoporosis as well as considering chronic bony pain in the same study.
There were three points of consideration of the impact of PEMFs on bone mineral density. First, some researchers considered that PEMFs enhanced bone mineral density.
As early as 1990, Tabrah et. al. reported that PEMFs increased BMD of osteoporosis-prone women. They exposed the nondominant forearms of 20 subjects to 72 Hz PEMF 10 hours daily for a period of 12 weeks and found that the bone mineral densities of the treated radius increased significantly in the immediate area of the field during the exposure period and decreased during the following 36 weeks while a similar but weaker response occurred in the opposite arm. BMD of lumbar as well as femoral neck, Wards triangle and Trochiscus in 116 patients who received therapy with PEMFs was higher after six months of therapy than in the placebo group.
There were also reports about the long-term effects of PEMFs on bone mineral density of osteoporosis patient from home and abroad. Tabrah et. al. remeasured the bone density of radii after eight years and found no long-term changes. Zhou et. al. found that the bone mineral density increased significantly 2–6 months after three 30-day periods of therapy. Liu et. al. observed that BMD was still higher than the control group 3–4 months after 30 days of therapy. Thus we inferred that the improved BMD effect of PEMFs can last for at least 3–4 months which indicated that osteoporosis patients would not be treated every day. But the long-term effect and safety of PEMFs, when comparing PEMFs alone or in combination with exercise and pharmacologic agents such as bisphosphonates and hormones, should be further studied because that osteoporosis develops with aging.
Although the effect of PEMFs on improving bone mineral density is still uncertain, an improving trend occurred. Low frequency, which is often below 50 Hz 20 MT, appropriated length of PEMFs therapy, which is at least 30 days would be good for osteoporosis patients.
Effect of PEMFs on bone strength in patients with osteoporosis
Zhang et. al. assessed the bone strength by ultrasound of group receiving PEMFs and drug treatment and a group receiving pharmacological therapy alone. They found that after treatment with PEMFs and drug, the broadband ultrasound attenuation (BUA), speed of sound (SOS) values of the right calcaneus were statistically greater than before while the values in pharmacological therapy group were not. But there was no comparison between the two groups.
Side effects of PEMFs
Ten studies observed no side effects of PEMFs stimulation by describing treatment response and testing blood, serum, liver and kidney function along with levels of serum calcium and phosphorus. None of them reported other side effects, thus PEMFs is approved as safe for osteoporosis by short term application.
PEMFs have been developed as a non-drug treatment for osteoporosis in recent years. Clinical studies have shown the therapeutic efficacy of PEMFs in primary and secondary osteoporosis which can relieve chronic bony pain quickly and efficiently with no side effects. But it is still being studied whether PEMFs enhances the bone mineral density of patients with primary osteoporosis.
The effect of PEMFs on biochemical markers of bone metabolism confirmed that PEMFs promoted bone formation which may partly elucidate the mechanism of PEMFs for osteoporosis.
1. Huang, L. Q., He, H. C., He, C. Q., Chen, J., & Yang, L. (2008). Clinical update of pulsed electromagnetic fields on osteoporosis. Chin Med J, 121(20), 2095-2099.
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