The Role of Whole-body Vibration in the Prevention of Postmenopausal Osteoporosis

Whole-body vibration (WBV) was recently introduced as a potential modality for strengthening bones, and this thesis was set out to investigate whether it plays a role in the prevention of postmenopausal bone loss. First, effects of WBV on bone mineral density (BMD) were systematically evaluated in previous randomized controlled trials (RCTs) in postmenopausal women. Second, a RCT of 202 postmenopausal women with primary osteopenia not on bone medications was conducted to investigate the effects of WBV at 0.3g and 90 Hz versus 0.3g and 30 Hz versus controls on various bone outcomes, as measured by dual-energy x-ray absorptiometry (DXA), high-resolution peripheral quantitative computed tomography (HR-pQCT), and quantitative ultrasound (QUS). In the systematic evaluation of previous RCTs, statistically significant increase in areal BMD (aBMD) at the hip was found in postmenopausal women receiving WBV versus controls, but the effect was small and may have been due to study bias. Also, WBV was not found to influence aBMD at the lumbar spine or volumetric BMD (vBMD) at the distal tibia in the systematic evaluation. In the RCT conducted in this thesis, no statistically significant effects of WBV were found on aBMD at the femoral neck, total hip or lumbar spine, as measured by DXA, or on vBMD or bone structure parameters at the distal tibia or distal radius, as measured by HR-pQCT. Further in this RCT, a statistically significant decrease was observed in QUS attenuation at the calcaneus in women receiving 90 Hz or 30 Hz WBV compared to controls. This may have been due to heel bone or soft tissue damage, although the effect was small and may not be clinically important. In conclusion, this investigation of postmenopausal women did not find clinically relevant benefits of WBV on osteoporotic-prone skeletal sites, including the hip, spine, tibia or radius, while potentially harmful effects on heel bone and/or soft tissue was observed in response to WBV. Thus based on this thesis, WBV is currently not recommended for the prevention of bone loss in community-dwelling postmenopausal women with primary osteopenia.Ph