Low magnitude whole body vibration does not improve bone density or bone structure

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A study published in the Annals of Internal Medicine shows that low magnitude whole body vibration does not affect bone mineral density or bone structure in postmenopausal women who received calcium and vitamin D supplementation.

Although initially touted as a potential therapy for preventing osteoporosis, whole body vibration has not been definitively shown to improve bone density or bone structure. While animal studies have shown the treatment, which involves the patient standing on a motor-driven, oscillating platform that produces vertical accelerations that are transmitted from the feet to the weight-bearing muscles and bones, to significantly improve bone formation rate, bone mineral density (BMD), trabecular structure, and cortical thickness, the results from studies in postmenopausal have been mixed.

 

Lubomira Slatkovska, University Health Network, Mount Sinai Hospital, University of Toronto, Canada, and her co-authors reported  that it has been hypothesised that whole body vibration might be a useful anti-osteoporosis therapy because its effect might include “changes in the flow of bone fluid caused by direct bone stimulation and transduction of mechanical signals, possibly through osteocytes and Wnt-β-catenin signalling, or indirect bone stimulation through skeletal muscle activation.”

 

At a single-centre, Slatkovska et al randomised postmenopausal women with BMD T-scores of between -1 and -2.5 to one of three groups: no whole body vibration (67); whole body vibration at 30Hz (68); and whole body vibration at 90Hz (67). Due to limited funding, investigators were not able to have a sham whole body vibration arm; therefore, patients did know if they were in the control but those in the active treatment groups did not know if they were in the 30Hz or 90Hz arm.

 

The primary endpoint of tibial trabecular volumetric BMD did not differ significantly between the three groups. Nor were any differences observed between the groups in areal BMD at the lumbar spine (mean absolute change from baseline at 12 months: -0.006 for 90hz, -0.008 for 30hz; and -0.007 for no treatment), femoral neck, and total hip.

 

Although, overall, at both 30hz and 90z, whole body vibration was well tolerated, greater decreases in trabecular thickness and separation and greater increases in trabecular number were seen in older patients (age >60 years or >10 years since menopause) in the whole body vibration groups compared with age-matched patients in the control group. No such differences were observed between younger patients in the three groups. Slatkovska et al reported: “Our results showed that whole body vibration at either 90 or 30Hz might have a detrimental effect on tibial trabecular structure in older postmenopausal women. However, the observed effects could have occurred by chance, because the subgroup of older participants was small and we performed multiple comparisons.”

 

Concluding their study, they said that low magnitude whole body vibration could not be recommended for preventing age-related bone loss in community-dwelling postmenopausal women who received calcium and vitamin D supplementation. However, they did say that whole body vibration might be more effective in children and adolescents with compromised bones because their skeletons are still growing. They added: “Randomised controlled trials of whole body vibration effects on bone are under way in adolescents, patients with spinal cord injury, and institutionalised elderly persons.”

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