The muscle-bone unit of peripheral and central skeletal sites in children and young adults.

UNLABELLED: Changes and gender differences in the muscle bone unit at different skeletal sites were investigated during pubertal development. Females accrued greater BMC in relation to muscle compared to males; these gender differences were greater after adjustment for height and regional fat mass. PURPOSE: To describe changes and gender differences in the muscle-bone unit at different skeletal sites during pubertal development. METHODS: Four hundred forty-two children aged 5-18 years were studied. Measurements of bone mineral content (BMC), lean mass (LM) and fat mass of the whole body (WB), legs, arms and lumbar spine were obtained from dual-energy X-ray absorptiometry. Peripheral quantitative computed tomography was used to measure BMC of the radius diaphysis and cross-sectional muscle area (CSMA) of the mid-forearm. These measurements were used to describe differences between, and within, genders at each pubertal stage in BMC accrual relative to muscle, both before and after adjustment for height, regional fat and muscle at central and peripheral skeletal sites. RESULTS: In males, there were significant increases in adjusted WB and leg BMC at the end of pubertal development. Unadjusted and adjusted lumbar spine BMC increased at the onset of, and at the end, of puberty. Radius BMC increased at most pubertal stages. In females, there were increases in unadjusted and adjusted whole body BMC at late puberty, in leg BMC at the onset of puberty and at pubertal stage four. Unadjusted arm BMC increased at most pubertal stages; however, after adjustment, an increase occurred at pubertal stage four. Both adjusted and unadjusted lumbar spine BMC increased at pubertal stage four. Unadjusted radius BMC increased at most pubertal stages. Females had greater BMC at all skeletal sites, compared to males, except at the radius, where adjusted BMC was greater in males at pubertal stage four. CONCLUSIONS: Males and females accrue more BMC in relation to lean mass at multiple skeletal sites as puberty proceeds. Females accrue more BMC in relation to lean mass, in comparison to males, at most skeletal sites.

A reference database for the Stratec XCT-2000 peripheral quantitative computed tomography (pQCT) scanner in healthy children and young adults aged 6-19 years.

SUMMARY: We have produced paediatric reference data for forearm sites using the Stratec XCT-2000 peripheral quantitative computed tomography scanner. These data are intended for clinical and research use and will assist in the interpretation of bone mineral density and bone geometric parameters at the distal and mid-shaft radius in children and young adults aged between 6-19 years. INTRODUCTION: Peripheral quantitative computed tomography (pQCT) provides measurements of bone mineral content (BMC), density (BMD) and bone geometry. There is a lack of reference data available for the interpretation of pQCT measurements in children and young adults. The aim of this study was to provide reference data at the distal and mid-shaft radius. METHODS: pQCT was used to measure the 4% and 50% sites of the non-dominant radius in a cohort of healthy white Caucasian children and young adults aged between 5 and 25 years. The lambda, mu, sigma (LMS) technique was used to produce gender-specific reference centile curves and LMS tables for calculating individual standard deviations scores. RESULTS: The study population consisted of 629 participants (380 males). Reference centile curves were produced; total and trabecular BMD for age (distal radius) and for age and height, bone area (distal and mid-shaft radius), cortical area, cortical thickness, BMC, axial moment of inertia, stress-strain index and muscle area (mid-shaft radius). CONCLUSIONS: We present gender-specific databases for the assessment of the distal and mid-shaft radius by pQCT. These data can be used as control data for research studies and allow the clinical interpretation of pQCT measurements in children and young adults by age and height.