Are there effects of age, gender, height, and body fat on the functional muscle-bone unit in children and adults?

The aim was to describe the effect of age, gender, height, different stages of human life, and body fat on the functional muscle-bone unit. All these factors had a significant effect on the functional muscle-bone unit and should be addressed when assessing functional muscle-bone unit in children and adults. INTRODUCTION: For the clinical evaluation of the functional muscle-bone unit, it was proposed to evaluate the adaptation of the bone to the acting forces. A frequently used parameter for this is the total body less head bone mineral content (TBLH-BMC) determined by dual-energy X-ray absorptiometry (DXA) in relation to the lean body mass (LBM by DXA). LBM correlates highly with muscle mass. Therefore, LBM is a surrogate parameter for the muscular forces acting in everyday life. The aim of the study was to describe the effect of age and gender on the TBLH-BMC for LBM and to evaluate the impact of other factors, such as height, different stages of human life, and of body fat. METHODS: As part of the National Health and Nutrition Examination Survey (NHANES) study, between the years 1999-2006 whole-body DXA scans on randomly selected Americans from 8 years of age were carried out. From all eligible DXA scans (1999-2004), three major US ethnic groups were evaluated (non-Hispanic Whites, non-Hispanic Blacks, and Mexican Americans) for further statistical analysis. RESULTS: For the statistical analysis, the DXA scans of 8190 non-Hispanic White children and adults (3903 female), of 4931 non-Hispanic Black children and adults (2250 female) and 5421 of Mexican-American children and adults (2424 female) were eligible. Age, gender, body height, and especially body fat had a significant effect on the functional muscle-bone unit. CONCLUSIONS: When assessing TBLH-BMC for LBM in children and adults, the effects of age, gender, body fat, and body height should be addressed. These effects were analyzed for the first time in such a large cohort.

The functional muscle-bone unit in children with cerebral palsy.

Our results suggest that the prevalence of bone health deficits in children with CP was overestimated, when using only age- and height-adjusted bone mineral content (BMC) and areal bone mineral density (aBMD). When applying the functional muscle-bone unit diagnostic algorithm (FMBU-A), the prevalence of positive results decreased significantly. We recommend applying the FMBU-A when assessing bone health in children with CP. INTRODUCTION: The prevalence of bone health deficits in children with cerebral palsy (CP) might be overestimated because age- and height-adjusted reference percentiles for bone mineral content (BMC) and areal bone mineral density (aBMD) assessed by dual-energy X-ray absorptiometry (DXA) do not consider reduced muscle activity. The aim of this study was to compare the prevalence of positive DXA-based indicators for bone health deficits in children with CP to the prevalence of positive findings after applying a functional muscle-bone unit diagnostic algorithm (FMBU-A) considering reduced muscle activity. METHODS: The present study was a monocentric retrospective analysis of 297 whole body DXA scans of children with CP. The prevalence of positive results of age- and height-adjusted BMC and aBMD defined as BMC and aBMD below the P3 percentile and of the FMBU-A was calculated. RESULTS: In children with CP, the prevalence of positive results of age-adjusted BMC were 33.3% and of aBMD 50.8%. Height-adjusted results for BMC and aBMD were positive in 16.8 and 36.0% of cases. The prevalence of positive results applying the FMBU-A regarding BMC and aBMD were significantly (p < 0.001) lower than using age- and height-adjusted BMC and aBMD (8.8 and 14.8%). CONCLUSIONS: Our results suggest that the prevalence of bone health deficits in children with CP was overestimated, when using age- and height-adjusted BMC and aBMD. When applying the FMBU-A, the prevalence decreased significantly. We recommend applying the FMBU-A when assessing bone health in children with CP.

Experience with jumping mechanography in children with cerebral palsy.

OBJECTIVES: Jumping mechanography provides robust motor function indicators among healthy children. The aim of the study was to assess the reproducibility and validity of jumping mechanography conducted as single two-legged jump (S2LJ) in children with cerebral palsy (CP). METHODS: 215 S2LJ investigations from a sample of 75 children with CP were eligible for evaluation. For the estimation of the reproducibility, only the baseline set of data per patient were used. Gross motor function was evaluated by the Gross Motor Function Measure (GMFM-66). In 135 S2LJ investigations, GMFM-66 was assessed within a week in the same child. This data was used for validity assessment. RESULTS: Coefficients of variation for the main outcome parameters ranged between 6.15-9.71%, except for jump height (CV%=27.3%). The intraclass correlation coefficients for peak velocity (Vmax) and peak power relative to body weight (Pmax/mass) was 0.927 and 0.931. Vmax and Pmax/mass were also the test parameters with the strongest correlation to the GMFM-66 score (⟩0.7). CONCLUSIONS: S2LJ assessed in the present study provided reproducible outcome measures particularly for Vmax and Pmax/mass in children with CP. Further, Vmax and Pmax/mass showed the strongest correlation with the GMFM-66 score and seem to be the most relevant evaluation criteria.

Changes in muscle cross-sectional area, muscle force, and jump performance during 6 weeks of progressive whole-body vibration combined with progressive, high intensity resistance training.

OBJECTIVES: We hypothesized that progressive whole-body vibration (WBV) superimposed to progressive high intensity resistance training has greater effects on muscle cross-sectional area (CSA), muscle force of leg muscles, and jump performance than progressive high intensity resistance training alone. METHODS: Two groups of healthy male subjects performed either 6 weeks of Resistive Vibration Exercise (RVE, squats and heel raises with WBV, n=13) or Resistive Exercise (RE, squats and heel raises without WBV, n=13). Squats under RVE required indispensable weight loading on the forefoot to damp harmful vibrations to the head. Time, intervention, and interaction effects were analyzed. RESULTS: After 6 weeks of training, knee extensor CSA, isometric knee extension force, and counter movement jump height increased equally in both groups (time effect, P⟨0.001, P≤0.02, and P≤0.03, respectively), whereas only in RVE ankle plantar flexor CSA and isometric ankle plantar flexion force reached significance or a tendency, respectively, (time effect, P=0.015 and P=0.069, respectively; intervention effect also for the latter, P=0.006). Drop jump contact time did significantly more improve in RVE (interaction effect, P=0.042). CONCLUSIONS: RVE showed better training effects than RE only in plantar flexor muscles. RVE seems to be suitable in professional sports with a special focus on calf muscles.

Home-based vibration assisted exercise as a new treatment option for scoliosis - A randomised controlled trial.

OBJECTIVES: The aim of this study was to evaluate the effect of scoliosis specific exercises (SSE) on a side-alternating whole body vibration platform (sWBV) as a home-training program in girls with adolescent idiopathic scoliosis (AIS). METHODS: 40 female AIS patients (10-17 years) wearing a brace were randomly assigned to two groups. The intervention was a six months, home-based, SSE program on a sWBV platform five times per week. Exercises included standing, sitting and kneeling. The control group received regular SSE (treatment as usual). The Cobb angle was measured at start and after six months. Onset of menarche was documented for sub-group analysis. RESULTS: The major curve in the sWBV group decreased significantly by -2.3° (SD±3.8) (95% CI -4.1 to -0.5; P=0.014) compared to the difference in the control group of 0.3° (SD±3.7) (95% CI -1.5 to 2.2; P=0.682) (P=0.035). In the sWBV group 20% (n=4) improved, 75% (n=15) stabilized and 5% (n=1) deteriorated by ≥5°. In the control group 0% (n=0) improved, 89% (n=16) stabilized and 11% (n=2) deteriorated. The clinically largest change was observed in the 'before-menarche' sub-group. CONCLUSIONS: Home-based SSE combined with sWBV for six months counteracts the progression of scoliosis in girls with AIS; the results were more obvious before the onset of the menarche.

Safety and efficacy of denosumab in children with osteogenesis imperfect--a first prospective trial.

OBJECTIVES: Osteogenesis imperfecta (OI) is a rare hereditary disease leading to bone fragility. Denosumab as a RANK ligand antibody inhibiting osteoclast maturation has been approved for osteoporosis treatment in adults. Aim of this study was a 48-week, open-label, pilot study of the safety and efficacy of denosumab in 10 children with OI. METHODS: Ten patients (age range: 5.0-11.0 years; at least two years of prior bisphosphonate treatment) with genetically confirmed OI were studied. Denosumab was administered subcutaneously every 12 weeks with 1 mg/kg body weight. Primary endpoint was change of areal bone mineral density (aBMD) using dual energy x-ray absorptiometry of the lumbar spine after 48 weeks. Safety was assessed by bone metabolism markers and adverse event reporting. RESULTS: Mean relative change of lumbar aBMD was +19 % (95%-CI: 7-31%). Lumbar spine aBMD Z-Scores increased from -2.23±2.03 (mean±SD) to -1.27±2.37 (p=0.0006). Mobility did not change (GMFM-88 +2.72±4.62% (p=0.16); one-minute walking test +11.00±15.82 m (p=0.15). No severe side effects occurred. CONCLUSIONS: On average, there was a significant increase in lumbar spine aBMD percent change after 48 weeks of denosumab. There was no change in mobility parameters and no serious adverse events. Further trials are necessary to assess long-term side effects and efficacy.

Early vibration assisted physiotherapy in toddlers with cerebral palsy - a randomized controlled pilot trial.

OBJECTIVES: to investigate feasibility, safety and efficacy of home-based side-alternating whole body vibration (sWBV) to improve motor function in toddlers with cerebral palsy (CP). METHODS: Randomized controlled trial including 24 toddlers with CP (mean age 19 months (SD±3.1); 13 boys). INTERVENTION: 14 weeks sWBV with ten 9-minute sessions weekly (non-individualized). Group A started with sWBV, followed by 14 weeks without; in group B this order was reversed. Feasibility (≥70% adherence) and adverse events were recorded; efficacy evaluated with the Gross Motor Function Measure (GMFM-66), Pediatric Evaluation of Disability Inventory (PEDI), at baseline (T0), 14 (T1) and 28 weeks (T2). RESULTS: Developmental change between T0 and T1 was similar in both groups; change scores in group A and B: GMFM-66 2.4 (SD±2.1) and 3.3 (SD±2.9) (p=0.412); PEDI mobility 8.4 (SD±6.6) and 3.5 (SD±9.2) (p=0.148), respectively. In two children muscle tone increased post-sWBV. 24 children received between 67 and 140 sWBV sessions, rate of completed sessions ranged from 48 to 100% and no dropouts were observed. CONCLUSION: A 14-week home-based sWBV intervention was feasible and safe in toddlers with CP, but was not associated with improvement in gross motor function.

Reactions of the rat musculoskeletal system to compressive spinal cord injury (SCI) and whole body vibration (WBV) therapy.

Traumatic spinal cord injury (SCI) causes a loss of locomotor function with associated compromise of the musculo-skeletal system. Whole body vibration (WBV) is a potential therapy following SCI, but little is known about its effects on the musculo-skeletal system. Here, we examined locomotor recovery and the musculo-skeletal system after thoracic (T7-9) compression SCI in adult rats. Daily WBV was started at 1, 7, 14 and 28 days after injury (WBV1-WBV28 respectively) and continued over a 12-week post-injury period. Intact rats, rats with SCI but no WBV (sham-treated) and a group that received passive flexion and extension (PFE) of their hind limbs served as controls. Compared to sham-treated rats, neither WBV nor PFE improved motor function. Only WBV14 and PFE improved body support. In line with earlier studies we failed to detect signs of soleus muscle atrophy (weight, cross sectional diameter, total amount of fibers, mean fiber diameter) or bone loss in the femur (length, weight, bone mineral density). One possible explanation is that, despite of injury extent, the preservation of some axons in the white matter, in combination with quadripedal locomotion, may provide sufficient trophic and neuronal support for the musculoskeletal system.

Neuromuscular training based on whole body vibration in children with spina bifida: a retrospective analysis of a new physiotherapy treatment program.

INTRODUCTION: Spina bifida is the most common congenital cause of spinal cord lesions resulting in paralysis and secondary conditions like osteoporosis due to immobilization. Physiotherapy is performed for optimizing muscle function and prevention of secondary conditions. Therefore, training of the musculoskeletal system is one of the major aims in the rehabilitation of children with spinal cord lesions. INTERVENTION AND METHODS: The neuromuscular physiotherapy treatment program Auf die Beine combines 6 months of home-based whole body vibration (WBV) with interval blocks at the rehabilitation center: 13 days of intensive therapy at the beginning and 6 days after 3 months. Measurements are taken at the beginning (M0), after 6 months of training (M6), and after a 6-month follow-up period (M12). Gait parameters are assessed by ground reaction force and motor function by the Gross Motor Function Measurement (GMFM-66). Sixty children (mean age 8.71 ± 4.7 years) who participated in the program until February 2014 were retrospectively analyzed. RESULTS: Walking velocity improved significantly by 0.11 m/s (p = 0.0026) and mobility (GMFM-66) by 2.54 points (p = 0.001) after the training. All changes at follow-up were not significant, but significant changes were observed after the training period. Decreased contractures were observed with increased muscle function. CONCLUSION: Significant improvements in motor function were observed after the active training period of the new neuromuscular training concept. This first analysis of the new neuromuscular rehabilitation concept Auf die Beine showed encouraging results for a safe and efficient physiotherapy treatment program which increases motor function in children with spina bifida.

A specialized rehabilitation approach improves mobility in children with osteogenesis imperfecta.

OBJECTIVE: Osteogenesis imperfecta (OI) is a rare disease leading to recurrent fractures, hyperlaxicity of ligaments, short stature and muscular weakness. Physiotherapy is one important treatment approach. The objective of our analysis was to evaluate the effect of a new physiotherapy approach including side alternating whole body vibration on motor function in children with OI. METHODS: In a retrospective analysis data of 53 children were analyzed. The 12 months approach included 6 months of side alternating whole body vibration training, concomitant physiotherapy, resistance training, treadmill training and 6 months follow up. Primary outcome parameter was the Gross Motor Function Measure after 12 months (M12). RESULTS: 53 children (male: 32; age (mean±SEM): 9.1±0.61, range 2.54-24.81 years) participated in the treatment approach. A significant increase of motor function (GMFM-66 score 55.47±2.45 to 58.67±2.83; p=0.001) and walking distance (47.04 m±6.52 to 63.36±8.25 m (p<0.01) between M0 and M12 was seen. Total body without head bone mineral density increased significantly at M12 (p=0.0189). CONCLUSIONS: In the cohort of OI children which participated in the specialized treatment approach improvements of motor function were observed. Therefore this program should be considered as additional therapeutic approach for children with severe OI.

[Secondary forms of osteoporosis. Special features of diagnostics in childhood and adolescence]. / Sekundäre Formen der Osteoporose. Besonderheiten der Diagnostik im Kindes- und Jugendalter.

Rheumatic diseases in childhood and adolescence can lead to secondary osteoporosis based on various pathophysiologies. The underlying disease, medication and immobility resulting in a reduced osteoanabolic stimulus contribute to the development of a fragile skeletal system. For diagnostic purposes dual-energy X-ray absorptiometry (DXA) is the most frequently used technology. For interpretation of the areal bone mineral density, age and gender matched reference data have to be used. Particularly in the pediatric field, body height must additionally be taken into consideration. Further techniques which can provide detailed information are peripheral quantitative computed tomography and high resolution magnetic resonance imaging. Nowadays, skeletal assessments have to be interpreted in the context of the muscular system. The concept of the functional muscle-bone unit is widely accepted and uses the muscles as the dominating factor. In a second step the adaptation of the skeletal system to the applied muscle force is evaluated. This allows a differentiation between primary and secondary skeletal diseases depending on the ratio of muscles to bone. Therapeutic options for secondary osteoporosis include reduction of the causative medication, treatment of the underlying disease, antiresorptive treatment with bisphosphonates and different programs to activate the muscles. A multimodal interval rehabilitation program including alternating side vibration shows positive effects on mobility, muscle function and bone mass in children and adolescents.

Randomized controlled study on resistive vibration exercise (EVE study): protocol, implementation and feasibility.

OBJECTIVES: A training intervention comparing resistance exercise with or without whole-body vibration (WBV) was conducted to compare acute and chronic effects on functional and molecular parameters. METHODS: A six-week training intervention was performed including 26 healthy males (26 years, SD=4). Two groups were analyzed in a parallel design performing either resistive exercise (RE, n=13) or resistive vibration exercise (RVE, n=13) training with weekly increasing vibration frequencies (20-40Hz). Resting and exercising blood pressure and heart rate were measured before and after the 6-week intervention. RESULTS: Both training interventions decreased resting systolic blood pressure (P=0.003). Resting diastolic blood pressure was significantly decreased only in the RVE group (P=0.01). Exercising diastolic blood pressure was significantly decreased during the final training (P<0.001) with no additional effect of superimposed vibrations. Resistance exercise with superimposed vibrations evoked back pain to a higher degree than resistance exercise alone when training at frequencies above 30Hz (P<0.01). CONCLUSIONS: These data suggest positive effects of resistance exercise upon cardiovascular health and vascular responsiveness and a further beneficial effect of superimposed vibrations in decreasing resting diastolic blood pressure. Finally, development of back pain may be fostered by superimposed vibrations to high training loads, particularly at higher frequencies.

First use of the RANKL antibody denosumab in osteogenesis imperfecta type VI.

UNLABELLED: Osteogenesis imperfecta (OI) is a genetically heterogeneous disease leading to bone fragility. OI-VI is an autosomal-recessive form caused by mutations in SERPINF1. There is experimental evidence suggesting that loss of functional SERPINF1 leads to an activation of osteoclasts via the RANK/RANKL pathway. Patients with OI-VI show a poor response to bisphosphonates. We report on four children with OI-VI who had shown continuously elevated urinary bone resorption markers during a previous treatment with bisphosphonates. We treated these children with the RANKL antibody denosumab to reduce bone resorption. INTERVENTION AND RESULTS: Denosumab (1 mg/kg body weight) was injected s.c. every 3 months. There were no severe side effects. Markers of bone resorption decreased to the normal range after each injection. N-terminal Propeptide of collagen 1 was measured in the serum during the first treatment cycle and decreased also. Urinary deoxypyridinoline/creatinine was monitored in a total of seven treatment cycles and indicated that bone resorption reached the pre-treatment level after 6-8 weeks. CONCLUSION: This was the first use of denosumab in children with OI-VI. Denosumab was well tolerated, and laboratory parameters provided evidence that the treatment reversibly reduced bone resorption. Therefore, denosumab may be a new therapeutic option for patients with OI-VI.

Effect of a new physiotherapy concept on bone mineral density, muscle force and gross motor function in children with bilateral cerebral palsy.

OBJECTIVE: The purpose of this study was to determine the effect of a new physiotherapy concept on bone density, muscle force and motor function in bilateral spastic cerebral palsy children. METHODS: In a retrospective data analysis 78 children were analysed. The concept included whole body vibration, physiotherapy, resistance training and treadmill training. The concept is structured in two in-patient stays and two periods of three months home-based vibration training. Outcome measures were dual-energy x-ray absorption (DXA), Leonardo Tilt Table and a modified Gross Motor Function Measure before and after six months of training. RESULTS: Percent changes were highly significant for bone mineral density, -content, muscle mass and significant for angle of verticalisation, muscle force and modified Gross Motor Function Measure after six months training. CONCLUSIONS: The new physiotherapy concept had a significant effect on bone mineral density, muscle force and gross motor function in bilateral spastic cerebral palsy children. This implicates an amelioration in all International Classification of Functioning, Disability and Health levels. The study serves as a basis for future research on evidence based paediatric physiotherapy taking into account developmental implications.

Reporting whole-body vibration intervention studies: recommendations of the International Society of Musculoskeletal and Neuronal Interactions.

Whole-body vibration (WBV) is receiving increasing interest as a therapeutic modality to improve neuromuscular performance or to increase bone mass or density. In order to help improve the quality of reports about WBV treatment studies, the International Society of Musculoskeletal and Neuronal Interactions (ISMNI) invited experts in the field to provide suggestions on how the intervention should be described in such reports. The recommendations are presented here.

Mechanographic analyses in pediatrics: allometric scaling of 'peak jump force' and its relationship to 'maximal isometric grip force' in childhood and adolescence.

BACKGROUND: Kinetic analyses of the neuromuscular system have become an important part in the diagnostics of metabolic bone disorders in pediatrics because of the relevance of the 'Functional Muscle-Bone Unit'. Because muscle function is associated with muscle metabolism, it is suggested that the association of maximal forces with anthropometric variables (e. g., body weight) is characterized by allometric scaling. The present manuscript aims to describe the scaling exponent for the association of maximal forces of mechanography and dynamometry to body weight and exemplarily applies the prediction of 'Peak Jump Force' (PJF) by 'Maximal Isometric Grip Force' (MIGF) for the characterization of the unconditioned neuromuscular system in subjects with congenital heart disease (CHD). SUBJECTS: MIGF was measured in a reference population of 135 school boys and 177 school girls who were not randomized individuals of a German primary and high-school. In addition, data of the neuromuscular system were analyzed in 29 individuals with CHD. METHODS: Participants performed counter-movement jumping on a force plate to measure PJF and v (max). MIGF was determined by dynamometric measurement. RESULTS: PJF scaled (body mass) (0.97) in girls and (body mass) (1.05) in boys. PJF was not different from the scaling exponent=1 in both genders. After having taken the logarithm, MIGF predicted PJF with R (2)(adjusted)=0.774 in boys, R (2)(adjusted)=0.720 in girls (p<0.001 each) and R (2)(adjusted)=0.209 (p=0.007) in patients with CHD. The mean of the predicted PJF was lower than the mean of the measured PJF in subjects with CHD (p<0.001). The difference between the predicted and the measured PJF (DeltaPJF) was associated with v (max) (R (2)(adjusted)=0.113, p=0.042). CONCLUSIONS: PJF scales body weight in an isometric way as recently describe for other vertebrates. MIGF is a good predictor of PJF in healthy children, but not in unconditioned individuals. DeltaPJF indicates conditioning of the individual and may be used to describe inter- and intramuscular coordination in children. HINTERGRUND: Mechanografische Analysen des neuromuskulären Systems haben mittlerweile auch einen diagnostischen Stellenwert in der Pädiatrie erlangt. Ziel der vorliegenden Untersuchung ist die kinetische Analyse des Counter-movement-Sprungs durch die Messung der Bodenreaktionskräfte in Hinblick auf seine allometrische Skalierung und im Vergleich zur Entwicklung der ,Maximalen isometrischen Griffstärke' (MIGF) bei Kindern und Jugendlichen. PROBANDEN: Die Studienpopulation umfasste 135 Schüler und 177 Schülerinnen, die nicht randomisiert wurden und Schüler einer deutschen Grundschule und eines deutschen Gymnasiums waren. Zudem wurden Daten von 29 Patienten mit kongenitalen Herzfehlern analysiert. METHODEN: Die Studienteilnehmer absolvierten Counter-movement-Sprünge auf einer Sprungplatte, sodass die maximale Sprungkraft (Peak Jump Force, PJF) und die maximale Geschwindigkeit des Massenschwerpunktes beim Absprung (v (max)) ermittelt werden konnten. MIGF wurde durch Messung mit einem Dynamometer bestimmt. ERGEBNISSE: PJF-skalierte (Körpermasse) (0,97) bei den Mädchen und (Körpermasse) (1,05) bei den Jungen. Der Skalierungsfaktor von PJF war bei Mädchen und Jungen nicht signifikant vom Faktor=1 verschieden. Nach Lograithmierung sagte die Variable MIGF den Parameter PJF in der Gruppe der Jungen mit R (2)(adjusted)=0,774, in der Gruppe der Mädchen mit R (2)(adjusted)=0,720 (jeweils p<0,001) und in der Gruppe der Herzkranken mit R (2)(adjusted)=0,209 (p=0,007) voraus. Der Mittelwert des vorhergesagten Wertes für PJF war niedriger als der Wert der gemessenen PJF in Patienten mit Herzerkrankung (p<0,001). Die Differenz zwischen vorhergesagter und gemessener PJF (DeltaPJF) stand statistisch mit v (max) (R (2)(adjusted)=0,113; p=0,042) in Zusammenhang. SCHLUSSFOLGERUNGEN: PJF skaliert isometrisch zur Körpermasse, wie es bereits für andere Vertebraten beschrieben wurde. MIGF ist ein guter Prädiktor für PJF bei gesunden Kindern und Jugendlichen, jedoch nicht bei Menschen mit einem unkonditionierten neuromuskulären System. DeltaPJF kann als Marker für die Konditionierung eines neuromuskulären Systems angesehen werden und beschreibt inter- und intramuskuläre Koordination.

Interaction of body fat percentage and height with appendicular functional muscle-bone unit.

The interaction of body fat percentage and height with appendicular BMC for LBM was analyzed. Only body fat had significant negative correlation with the appendicular BMC for LBM. PURPOSE/INTRODUCTION: For the clinical evaluation of the functional muscle-bone unit, it was proposed to evaluate the adaptation of the bone to the acting forces. A frequently used parameter for this is the total body less head bone mineral content (TBLH-BMC) determined by dual-energy X-ray absorptiometry (DXA) in relation to the total body lean body mass (LBM). Body fat percentage seemed to correlate negatively and height positively with TBLH-BMC for LBM. It was supposed that appendicular BMC for LBM is a more accurate surrogate for the functional muscle-bone unit since appendicular LBM does not incorporate the mass of internal organs. The aim of this study was to analyze the interaction of body fat percentage and height with appendicular BMC for LBM. METHODS: As part of the National Health and Nutrition Examination Survey (NHANES) study, between the years 1999 and 2004, whole-body DXA scans on randomly selected Americans from 8 years of age were carried out. From all eligible DXA scans, three major US ethnic groups were evaluated (non-Hispanic Whites, non-Hispanic Blacks, and Mexican Americans) for further statistical analysis. RESULTS: For the statistical analysis, the DXA scans of 8190 non-Hispanic White children and adults (3903 female), of 4931 non-Hispanic Black children and adults (2250 female), and 5421 of Mexican American children and adults (2424 female) were eligible. Only body fat had a significant negative correlation with the appendicular BMC for LBM. CONCLUSIONS: Only body fat had significant negative correlation with appendicular BMC for LBM, and thus, should be addressed when evaluating functional muscle-bone unit.

Peripheral quantitative computed tomography of the proximal radius in young subjects--new reference data and interpretation of results.

The aim of this contribution is to provide reference data for peripheral quantitative computed tomography (Stratec XCT2000) performed at the proximal radius (the so-called '65% site') of young subjects and to discuss the interpretation of such analyses. Data from a previous reference data study on 469 subjects between 6 and 40 years were re-analyzed and smooth curves were fitted. The corresponding equations allow for calculation of age-, height- and sex-specific z-scores of total cross-sectional area, cortical cross-sectional area, bone mineral content, cortical bone mineral density, total bone mineral density, Strength-Strain Index, muscle cross-sectional area and the ratio between bone mineral content and muscle cross-sectional area. These data should facilitate the clinical use of peripheral quantitative computed tomography in young subjects.

The influence of auxology and long-term glycemic control on muscle function in children and adolescents with type 1 diabetes mellitus.

We intended to investigate in this pilot-study if long-term glycemic control stands in close relationship with muscle function in children and adolescents with type 1 diabetes mellitus (T1DM). Muscle function (MIGF, maximal isometric grip force; PJF, peak jump force; PJP, peak jump power) was investigated in 40 children and adolescents (males 20, females 20; age 13.5-/+2.5 yr) affected with T1DM. Muscular parameters were correlated with anthropometric parameters (age, height, weight) and with glycosylated hemoglobin (HbA1c) of the presence and the past. Standard deviation scores (SDSs) of weight and MIGF indicated significantly higher weight (mean 0.75-/+1.83 (SD)) and lower MIGF (mean -1.06-/+1.76 (SD)) in individuals with T1DM. When the study group was divided into two groups by the criteria that the actual HbA1c (HbA1c0) was lower (N=25) or higher (N=15) than 8.5%, the comparison showed significantly higher muscular parameters (PJF-SDS, PJP-SDS and MIGF-SDS) in individuals with higher HbA1c0. Multiple regression analyses demonstrated that body weight and height primarily predicted muscle force (MIGF, PJF) in T1DM. In conclusion, skeletal growth is an important determinant for the development of muscle function in children and adolescents with T1DM.

Individualized evaluation of lumbar bone mineral density in children with cerebral palsy.

Lumbar spine bone mineral density (LS-BMD) assessed by dual-energy X-ray absorptiometry (DXA) is used in children with cerebral palsy (CP) to evaluate bone health. LS-BMD results in children with CP are influenced significantly by their height, BMI, and mobility level. An adjustment for these parameters might improve the clinical significance of the method. PURPOSE/INTRODUCTION: DXA evaluation is considered useful in children with CP to assess bone health. For this purpose, LS-BMD is often used. The aim of the study was to estimate the effect of height, BMI, and reduced mobility level of children with CP on LS-BMD and to develop a method to adjust individual results of LS-BMD for these factors. METHODS: We conducted a monocentric retrospective analysis of data collected in children and adolescents with CP, who participated in a rehabilitation program and had no history of recurrent fractures. The DXA scan was part of the routine examination for participants older than 4 years of age. The relationship between height and BMI for age Z-scores and age-adjusted LS-BMD Z-scores was analyzed. RESULTS: LS-DXA scans of 500 children and adolescents with CP (Gross Motor Function Classification System levels I-V) were included in the statistical analysis (217 female). The mean age was 9.4 years (± 3.7 years). Children with moderate to severe CP had significantly (p < 0.001) lower LS-BMD Z-scores than children with mild CP. We provided nomograms to adjust individual LS-BMD results to their height, BMI, and mobility level. CONCLUSIONS: LS-BMD results in children with CP were influenced significantly by their height, BMI, and mobility level. An adjustment of the LS-BMD results to height, BMI, and mobility level might improve the clinical significance of an individual result.