The Journal of clinical endocrinology and metabolism 2017 05 03() doi 10.1210/jc.2017-00275
Osteogenesis imperfecta (OI) is a bone fragility disorder associated with reduced muscle size, dynamic muscle function and mobility.
To assess the effect of whole body vibration (WBV) training on bone density and geometry, muscle size and function, mobility, and balance in children with OI.
Randomised controlled pilot trial.
Tertiary paediatric research centre.
Twenty-four children (5-16 years) with OI types 1,4 and limited mobility (CHAQ score ≥0.13) recruited in gender- and pubertal stage-matched pairs. Incident fractures in two boys (WBV arm) led to exclusion of two prepubertal male pairs.
5 months of WBV training (3x3min twice daily) or regular care.
Main Outcome Measures
Bone and muscle variables measured by dual-energy X-ray absorptiometry (lumbar spine, hip, total body) and peripheral quantitative computed tomography (distal and proximal tibia). Mobility assessed by six-minute walk tests and CHAQ; dynamic muscle function by mechanography.
All participants had reduced walking distances and dynamic muscle function (p<0.001). BMI Z-score was associated with higher CHAQ scores (rho +0.552; p=0.005) and lower walking and two-leg jumping performance (rho -0.405 to -0.654, p<0.05). The WBV and control groups did not differ in the 5-month changes in bone density or geometry. Total lean mass increased more in the WBV group (+1119g [+224 to +1744]) compared to controls (+635g [-951 to +1006]), p=0.01, without improving mobility, muscle function or balance. Conclusions
The increase in lean mass without changes in muscle function or bone mass suggests reduced biomechanical responsiveness of the muscle-bone unit in children with OI.