Abstract
CONTEXT: Spinal-cord injury (SCI) induces bone loss and dramatically increases the risk of fracture. OBJECTIVES: Determine the effects of whole-body vibration (WBV) on areal bone mineral density (aBMD), whole body composition and bone biological parameters in individuals with chronic-state SCI. DESIGN: Randomized study. SETTING: Centre Neurologique PROPARA. PARTICIPANTS: Fourteen subjects were randomly assigned to a WBV or a control group. INTERVENTIONS: WBV (20-45 min, 30-45 Hz, 0.5 g) was performed in verticalized persons twice weekly for 6 months. OUTCOME MEASURES: aBMD was measured by DXA at baseline and 6 months and bone biological parameters at baseline, 1, 3 and 6 months. RESULTS: No significant aBMD change was found in either the WBV or control group after 6 months of follow-up. Similarly, periostin, sclerostin and bone turnover markers remained relatively stable throughout follow-up and no difference in variation was observed within-group and between groups. Except for whole-body fat mass, which showed a significant decrease in the WBV group compared to controls, no difference in changes was observed, whatever the localization for fat and lean body mass. CONCLUSIONS: During the chronic phase, aBMD and bone remodeling reach a new steady state. However, the DXA technique and the bone markers, including sclerostin and periostin, both of which reflect bone cell activity influenced by mechanical strain, showed that the bone tissue of individuals with SCI was insensitive to 6 months of WBV training at the study dose. Nevertheless, results of this preliminary study that was underpowered need to be confirmed and other modalities of WBV may be more effective in improving aBMD of this population. TRIALS REGISTRATION: N°IDRCB:2011-A00224-37.