Background Preclinical studies showed that low-magnitude mechanical stimuli at a high frequency induce bone formation in rats [1]. But clinical studies in osteoporosis using whole body vibration (WBV) with bone mineral density evaluation as an endpoint showed variable treatment effects possibly related to small sample sizes, variable co-medication background and compliance issues [2,3,4]. Biomarkers for bone remodelling (formation and resorption) have been suggested as alternative endpoints.

Objectives To establish the effect of (WBV) on biomarkers of bone remodelling, fall risk and low back pain in postmenopausal women with osteoporosis using either raloxifen or alendronate as comedication.

Methods For this 12 week, multicentered, randomized, cross-over study, 58 postmenopausal woman with osteoporosis were stratified into those on treatment with alendronate (n=41) or raloxifene (n=17) and subsequently randomised to receive either WBV or no WBV during the first 6-week period of the study. WBV using Fitvibe® medical equipment (Uniphy Elektromedizin GmbH & Co. KG, Germany) was performed at three sessions per week with a minimum of 15 sessions within a periode of 6 weeks. One session consisted of 10 runs of 30 sec vibration intervals with a 15 sec plateau at a frequency of 30 Hz and an amplitude of 2 mm. At 6 weeks after baseline, patients who were initially randomized to the WBV group were observed for another 6 weeks without WBV in the second period of the study, whereas those who did not receive WBV in period 1 were treated with WBV for the remaining 6 weeks. Treatment effects were evaluated at 3, 6, 9 and 12 weeks using the biomarkers for bone remodeling (Ostase and DXPX), fall risk was evaluated by the Tinetti mobility test and low back pain was evaluated by an 11 point numerical scale. For the statistical evaluation, a two-period crossover-analysis Wilcoxon test (two-sided test for difference) for sums, differences and crossover differences was performed.

Results No significant treatment effects were seen for the biomarkers of bone remodelling (p=0.857 and 0.778). In contrast to this, effects on both low back pain (p=0.0049) and fall risk (p=0.0023) were highly significant. Those effects were confirmed for the alendronate group (pain: p=0.0002, fall risk p<0.0000) but not for the raloxifene patients (p=0.963 and 0.457, respectively). This difference might be due to baseline inhomogeneity. The alendronate group presented higher baseline pain and fall risk as compared to the raloxifene group. If baseline severity was used as a stratifying factor, the group with higher baseline pain and fall risk showed substantially more pronounced treatment effects than those with low values.

Conclusions WBV over 6 weeks has no significant effect on biomarkers of bone remodelling but may substantially improve low back pain and reduce fall risk. WBV appears to be a valuable addition for the symptomatic treatment of pain and fall risk in postmenopausal woman with osteoporosis.

1. Rubin et al. FASB J (2001) 15: 2225-2229

2. Rubin et al. J Bone Miner Res (2004) 19:343-351

3. Ruan et al. Chin Med J (2008) 121: 1155-1158

4. Verschueren et al. J Bone Miner Res (2004) 19: 352-359

Disclosure of Interest M. Rother Grant/Research support from: “Zentrales Innovationsprogramm Mittelstand des Bundesministeriums für Wirtschaft und Technologie” (grant number EP090750), E. Seidel: None Declared, W. Kneer: None Declared, G. Baumann: None Declared, I. Rother Grant/Research support from: “Zentrales Innovationsprogramm Mittelstand des Bundesministeriums für Wirtschaft und Technologie” (grant number EP090750)