Bone Mineral Content Values Research Articles

The impact of excess body fat on bone remodeling in adolescents.

The aim of this study was to investigate the impact of excess body fat on bone remodeling in adolescents. Body weight, height, and body mass index were determined in 391 adolescents classified as normal weight, overweight, obese, and extremely obese. Bone age was obtained and bone mineral content and bone mineral density were evaluated in the lumbar spine, proximal femur, and total and subtotal body. Blood samples were collected for evaluation of the following bone biomarkers: osteocalcin, bone alkaline phosphatase (BAP), and serum carboxy-terminal telopeptide (S-CTx). The data were analyzed according to nutritional status and age. In girls with excess weight, the biomarkers were higher in the 10 to 13-year age group and no significant differences were observed between groups according to nutritional status. In boys, the levels were higher in those aged 13 to 15years. According to nutritional status, significant differences were only observed in mean S-CTx for the age groups of 10-15years, with higher levels between overweight and obese adolescents aged 10-12years and between obese and extremely obese adolescents aged 13-15years. In girls, significant negative correlations were observed between lean mass, fat mass, and fat percentage and each of the three bone markers studied. There was no correlation between lean mass or fat mass and the three biomarkers in boys. The biomarker trends demonstrated across the age groups follow the age trends for growth velocity. The higher the fat percentage and fat mass in girls, the lower the levels of the biomarkers, indicating that excess body fat has a negative effect on the evolution of these markers during adolescence.

Association of different types of playing surfaces with bone mass in growing girls

ABSTRACTThe aim of this cross-sectional study was to compare bone mass in young female athletes playing ball games on different types of playing surfaces. About 120 girls, 9–13 years of age (10.6 ± 1.5 years old Tanner I–III) were recruited and divided into prepubertal and pubertal groups. The sample represented 3 groups of athletes: soccer (N = 40), basketball (N = 40), and handball (N = 40); and 6 different playing surfaces (soccer – ground, soccer – artificial turf, basketball – synthetic, basketball – parquet, handball – synthetic, and handball – smooth concrete). Total and regional body composition (bone mass, fat mass, and lean mass) were measured by dual-energy X-ray absorptiometry (DXA). The mechanical properties of the surfaces (force reduction, vertical deformation, and energy return) were measured with the Advanced Artificial Athlete (Triple A) method. The degree of sexual development was determined using Tanner test. The pubertal group showed that soccer players on the ground, basketball players on synthetic, and handball players on smooth concrete had higher values of bone mineral content (BMC) and bone mineral density (BMD) (P < 0.05) than the soccer players on the artificial turf, basketball players on parquet, and handball players on synthetic. In conclusion, a hard playing surface, with less vertical deformation and force reduction, and greater energy return, is associated with higher levels of BMD and BMC in growing girls, regardless of the sport they practice.

Validation of Dual-energy X-Ray Absorptiometry to Predict Body Composition of Channel Catfish, Ictalurus punctatus.

Dual-energy X-ray absorptiometry (DXA) provides a noninvasive way to determine lean tissue mass (LTM), fat mass (FM), bone mineral content (BMC), and bone mineral density (BMD) in humans and small mammals. Live channel catfish (n=74, 78g - 1200 g) were anesthetized and scanned in both a lateral position and a dorsa-ventral position. Six individual fish (300g - 600g) were scanned five times each to determine precision by the coefficient of variation. Precision was good for LTM (0.75-1.06%) and for BMC and BMD (2-2.6%). Precision for FM was not good (27-34%), which was due to the very low FM (0-1g) recorded by the DXA. However, using the predicted values, FM precision improved to 5-5.5%. DXA values for LTM, FM, and BMC were significantly different from chemical analysis (P< 0.001). DXA overestimated LTM and underestimated FM and BMC. However, all three compartments were strongly correlated with carcass values (P <0.0001). Using the prediction equations and the jackknife procedure, predicted values of LTM, FM, and BMC were not significantly different from the carcass values (P >0.05). DXA may also be a valuable tool for evaluating body condition longitudinally in commercial or in threatened or endangered fish species, where non-invasive procedures would be invaluable.

The effect of an 8-month exercise program on bone density and some physical characteristics in sedentary women

The aim of the study was to determine and evaluate the effect of an 8-month step-aerobic and run-walk exercise on bone density and some physical characteristics as weight, total fat mass, total fat percentile and lean mass at sedentary females 14 sedentary females with mean age 37.4 voluntarily participated in the study. Subjects performed an exercise program lasted an hour three days a week for eight months. Exercise program consisted of 45/50- minute step-aerobic one day a week; 30- minute run/walk and 30- minute stretching two days a week. Total bone mineral density (BMD), total bone mineral content (BMC), T score, Z score, Total lean mass, total fat mass and total fat percentile values were diagnosed by dual X-ray absorptiometry (DXA) (Norland XR-46). Wilcoxon signed rank test was used for data evaluation and significance level alpha was set at 0.05. After the eight -month exercise program, it was found out that there was significant decrease in weight, BMI, and total fat mass (p<0.05). But the decreases in total fat percentile and lean mass were statically insignificant. Nevertheless the increasing in total BMD, T - score and Z-score were statically significant (p<0.05), while the decreases in total BMC value were statically insignificant. In conclusion the eight-month step-aerobic, run-walk and stretching exercises positively affected some anthropometric components as weight, BMI, and total fat mass. However the program didn’t affect bone mineral contend in a positive way. But the program provides a preventive effect on bone density. It is suggested that preparation of exercise programs with similar purpose should include resistance exercise forms as well.

Longitudinal Effects Of Swimming On Bone Mass, Structure And Strength

PURPOSE: To investigate the changes over a swimming season in bone mineral density (BMD), bone mineral content (BMC), bone strength and bone structure in adolescent swimmers and compared them to normo-active controls (CG). METHODS: BMD and BMC were measured longitudinally (8 months) by Dual Energy X-ray Absorptiometry at the whole body, lumbar spine and non-dominant hip. Bone strength was measured at the midshaft radius and tibia with peripheral quantitative computed tomography (pQCT). Swimmers were divided into two groups; swimmers that swam and performed an extra-weight bearing sport (SWI-SPORT; n=11) and swimmers that only swam (SWI; n=23). Both groups were compared between them and to CG (n=28). ANCOVA for repeated measures x 2 (time) were performed between pre- and post-intervention to determine the effects of swimming on BMC and BMD values adjusting by change in height and subtotal lean, initial age and final Tanner stage and calcium intake for DXA values. For pQCT the same analyses were performed adjusting by change in object length, initial age and final Tanner stage. RESULTS: Eight months of swimming training had no effect on BMD or BMC, as no differences were found between SWI-PURE and CG acquisition. Nevertheless, practicing an extra-weight bearing sport in addition to swimming seemed to positively stimulate bone mass acquisition as SWI-SPORT was the only group that improved all measured skeletal sites and also a group by time interaction was found for the trochanter and total hip BMD when comparing SWI-SPORT to CG (p<0.05). Regarding pQCT measures, no group by time interactions were found for the radius. For the tibia, SWI-SPORT presented higher improvements in cortical thickness, resistance to fracture load (X-axis), and polar strain index than CG (all group by time interactions p<0.05). SWI-PURE also presented higher improvements in polar strain index when compared to CG (group by time interaction p<0.05). CONCLUSION: Swimming seems to be a neutral sport to practice regarding BMD and BMC acquisition. Nevertheless, it might entail some minor improvements in bone strength. Practicing a weight bearing sport in addition to swimming improves both bone mass acquisition and bone strength. Supported by the Spanish ‘Ministerio de Ciencia e Innovación’ ‘Plan Nacional I+D+i 2008-2011 (Project DEP DEP2011-29093)

Higher bone mass in prepubertal and peripubertal female footballers

Objectives: The main aim of this study was to compare the bone mass of female football players with controls of different pubertal stages. Methods: Sixty five girls aged 8–14 years (10.14 ± 0.1, Tanner stages I–IV) participated in the study. Twenty participants were prepubertal (10 prepubertal control) and 45 peripubertal (15 peripubertal control). All footballers trained two days per week while the control group did not perform regular physical activity outside of school. Body composition was assessed by Dual-energy X-ray absorptiometry. Analysis of covariance was performed to evaluate differences in lean and bone masses. Results: Significant differences in lower-body extremities lean mass (LLM) between peripubertal groups were found (P < .05). Additionally, prepubertal footballers showed higher values of bone mineral content (BMC) at the femoral neck (P < .05) while peripubertal footballers exhibited enhanced BMC at the whole-body, trochanter and Wards triangle area. Bone mineral density (BMD) was higher in footballers compared to their non-active peers at the femoral neck and intertrochanter (P < .05, respectively) while in the peripubertal footballers higher BMD values were found in almost all of the studied body sites. Conclusion: Female footballers showed higher bone and lean masses compared to control counterparts; these differences are already detectable at prepubertal ages and more consistent after pubertal spurt.

Assessment of bone mineral content and fracture risk: a UK prospective cohort study

BackgroundPoor early growth is associated with reduced adult bone mineral content (BMC), but not bone mineral density (BMD). Although low BMD is a well-established risk factor for future fracture, little is known about the performance characteristics of BMC in fracture prediction. We therefore investigated the predictive value of bone area, BMC, and BMD for incident fracture in a prospective cohort of UK women. MethodsWomen aged 20–80 years, recruited from four general practices in Southampton, underwent assessment by dual energy X-ray absorptiometry between 1991 and 1993. All women were then contacted in 1998–99 with a validated postal questionnaire to collect information on incident fractures and potential confounding factors including medication use. All fractures were confirmed by assessment of images and radiology reports by a research nurse. Cox proportional hazards models were used to explore the risk of incident fracture and results expressed as gradient of risk (GR) and 95% CI. Associations were adjusted for age, body-mass index, alcohol consumption, smoking, hormone replacement therapy, medications, and history of fracture. This study was approved by the Southampton Joint Ethics Committee. Findings674 women were recruited and 443 responded to the questionnaire. 55 women (12%) reported a fracture. In fully adjusted models, femoral neck BMC and BMD were similarly predictive of incident fracture (GR 1·64, 95% CI 1·19–2·26 [p=0·002] and 1·76, 1·19–2·60 [p=0·005], respectively). By contrast, femoral neck bone area was not associated with incident fracture (1·15, 0·88–1·50; p=0.32). Similar results were found with bone indices at the lumbar spine and whole body. InterpretationBMC and BMD seem to predict incident fracture with similar gradients of risk, even after adjustment for body size. These findings suggest that factors in early life that are associated with total skeletal mineralisation are likely to have implications for adult fracture risk. FundingMedical Research Council; British Heart Foundation; Arthritis Research UK; National Osteoporosis Society; International Osteoporosis Foundation; National Institute for Health Research (NIHR) Southampton Biomedical Research Centre, University of Southampton and University Hospital Southampton NHS Foundation Trust; NIHR Musculoskeletal Biomedical Research Unit, University of Oxford.

The effect of chronic mild hyponatremia on bone mineral loss evaluated by retrospective national Danish patient data

PurposeTo evaluate the effect of chronic mild hyponatremia ([Na+]=130–137mmol/L) on bone mineral content (BMC) and bone mineral density (BMD) loss through multiple, serial dual-energy X-ray absorptiometry (DXA) scans. MethodsUtilizing biochemical and DXA scan data from two Danish regions between 2004 and 2011, supplemented with national Danish patient diagnosis and prescription reimbursement databases, a retrospective cohort study was performed. All subjects with more than one DXA scan were included, then stratified into “normonatremia” ([Na+]=[137.00–147.00] mmol/L) and “mild hyponatremia” ([Na+]=[130.00–137.00[mmol/L) based on mean and confidence interval (CI) values calculated from all plasma sodium measurements between each subject's first and last DXA scan. Baseline, follow-up and delta values for hip and lumbar spine BMC and BMD were estimated between groups, then adjusted for comorbidity and medication use. ResultsHip and lumbar spine groups had 884 and 1069 patients with “normonatremia” versus 58 and 58 patients with “mild hyponatremia”, respectively. Mild hyponatremia was associated with lower BMC and BMD in nearly all regions of the hip, and with worse losses in the trochanteric, femoral neck and total hip regions. Mild hyponatremia had limited effect on the lumbar spine. ConclusionsChronic mild hyponatremia seems to greatly affect bone in the hip, while the effect is limited in the lumbar spine. We suggest further retrospective study of patients with moderate (P–Na=120–130mmol/L) to severe hyponatremia (P–Na<120mmol/L) and prospective studies to further examine the association.

Benefits of biphasic calcium phosphate hybrid scaffold-driven osteogenic differentiation of mesenchymal stem cells through upregulated leptin receptor expression.

BackgroundThe use of mesenchymal stem cells (MSCs) and coralline hydroxyapatite (HA) or biphasic calcium phosphate (BCP) as a bone substitute for posterolateral spinal fusion has been reported. However, the genes and molecular signals by which MSCs interact with their surrounding environment require further elucidation.MethodsMSCs were harvested from bone grafting patients and identified by flow cytometry. A composite scaffold was developed using poly(lactide-co-glycolide) (PLGA) copolymer, coralline HA, BCP, and collagen as a carrier matrix for MSCs. The gene expression profiles of MSCs cultured in the scaffolds were measured by microarrays. The alkaline phosphatase (ALP) activity of the MSCs was assessed, and the expression of osteogenic genes and proteins was determined by quantitative polymerase chain reaction (Q-PCR) and Western blotting. Furthermore, we cultured rabbit MSCs in BCP or coralline HA hybrid scaffolds and transplanted these mixtures into rabbits for spinal fusion. We investigated the differences between BCP and coralline HA hybrid scaffolds by dual-energy X-ray absorptiometry (DEXA) and computed tomography (CT).ResultsTested in vitro, the cells were negative for hematopoietic cell markers and positive for MSC markers. There was higher expression of 80 genes and lower of 101 genes of MSCs cultured in BCP hybrid scaffolds. Some of these genes have been shown to play a role in osteogenesis of MSCs. In addition, MSCs cultured in BCP hybrid scaffolds produced more messenger RNA (mRNA) for osteopontin, osteocalcin, Runx2, and leptin receptor (leptin-R) than those cultured in coralline HA hybrid scaffolds. Western blotting showed more Runx2 and leptin-R protein expression in BCP hybrid scaffolds. For in vivo results, 3D reconstructed CT images showed continuous bone bridges and fusion mass incorporated with the transverse processes. Bone mineral content (BMC) values were higher in the BCP hybrid scaffold group than in the coralline HA hybrid scaffold group.ConclusionsThe BCP hybrid scaffold for osteogenesis of MSCs is better than the coralline HA hybrid scaffold by upregulating expression of leptin-R. This was consistent with in vivo data, which indicated that BCP hybrid scaffolds induced more bone formation in a spinal fusion model.

Aged-Related Changes in Body Composition and Association between Body Composition with Bone Mass Density by Body Mass Index in Chinese Han Men over 50-year-old.

ObjectivesAging, body composition, and body mass index (BMI) are important factors in bone mineral density (BMD). Although several studies have investigated the various parameters and factors that differentially influence BMD, the results have been inconsistent. Thus, the primary goal of the present study was to further characterize the relationships of aging, body composition parameters, and BMI with BMD in Chinese Han males older than 50 years.MethodsThe present study was a retrospective analysis of the body composition, BMI, and BMD of 358 Chinese male outpatients between 50 and 89 years of age that were recruited from our hospital between 2009 and 2011. Qualified subjects were stratified according to age and BMI as follows: 50–59 (n = 35), 60–69 (n = 123), 70–79 (n = 93), and 80–89 (n = 107) years of age and low weight (BMI: < 20 kg/m2; n = 21), medium weight (20 ≤ BMI < 24 kg/m2; n = 118), overweight (24 ≤ BMI < 28 kg/m2; n = 178), and obese (BMI ≥ 28 kg/m2; n = 41). Dual-energy X-ray absorptiometry (DEXA) was used to assess bone mineral content (BMC), lean mass (LM), fat mass (FM), fat-free mass (FFM), lumbar spine (L1-L4) BMD, femoral neck BMD, and total hip BMD. Additionally, the FM index (FMI; FM/height2), LM index (LMI; LM/height2), FFM index (FFMI; [BMC+LM]/height2), percentage of BMC (%BMC; BMC/[BMC+FM+LM] × 100%), percentage of FM (%FM; FM/[BMC+FM+LM] × 100%), and percentage of LM (%LM; LM/(BMC+FM+LM) × 100%) were calculated. Osteopenia or osteoporosis was identified using the criteria and T-score of the World Health Organization.ResultsAlthough there were no significant differences in BMI among the age groups, there was a significant decline in height and weight according to age (p < 0.0001 and p = 0.0002, respectively). The LMI and FFMI also declined with age (both p < 0.0001) whereas the FMI exhibited a significant increase that peaked in the 80-89-years group (p = 0.0145). Although the absolute values of BMC and LM declined with age (p = 0.0031 and p < 0.0001, respectively), there was no significant difference in FM. In terms of body composition, there were no significant differences in %BMC but there was an increase in %FM (p < 0.0001) and a decrease in %LM (p < 0.0001) with age. The femoral neck and total hip BMD significantly declined with age (p < 0.0001 and p = 0.0027, respectively) but there were no differences in L1-L4. BMD increased at all sites (all p < 0.01) as BMI increased but there were declines in the detection rates of osteoporosis and osteopenia (both p < 0.001). A logistic regression revealed that when the medium weight group was given a BMI value of 1, a decline in BMI was an independent risk factor of osteoporosis or osteopenia, while an increase in BMI was a protective factor for BMD. At the same time, BMD in L1-L4 exhibited a significant positive association with FMI (p = 0.0003) and the femoral neck and total hip BMDs had significant positive associations with FFMI and LMI, respectively (both p < 0.0001).ConclusionsThese data indicate that LMI and FFMI exhibited significant negative associations with aging in Chinese Han males older than 50 years, whereas FMI had a positive association. BMD in the femoral neck and total hip declined with age but an increased BMI was protective for BMD. LMI and FFMI were protective for BMD in the femoral neck and total hip.

A DXA Whole Body Composition Cross-Calibration Experience: Evaluation With Humans, Spine, and Whole Body Phantoms

New densitometer installation requires cross-calibration for accurate longitudinal assessment. When replacing a unit with the same model, the International Society for Clinical Densitometry recommends cross-calibrating by scanning phantoms 10 times on each instrument and states that spine bone mineral density (BMD) should be within 1%, whereas total body lean, fat, and %fat mass should be within 2% of the prior instrument. However, there is limited validation that these recommendations provide adequate total body cross-calibration. Here, we report a total body cross-calibration experience with phantoms and humans.Cross-calibration between an existing and new Lunar iDXA was performed using 3 encapsulated spine phantoms (GE [GE Lunar, Madison, WI], BioClinica [BioClinica Inc, Princeton, NJ], and Hologic [Hologic Inc, Bedford, MA]), 1 total body composition phantom (BioClinica), and 30 human volunteers. Thirty scans of each phantom and a total body scan of human volunteers were obtained on each instrument.All spine phantom BMD means were similar (within 1%; <−0.010 g/cm2 bias) between the existing and new dual-energy X-ray absorptiometry unit. The BioClinica body composition phantom (BBCP) BMD and bone mineral content (BMC) values were within 2% with biases of 0.005 g/cm2 and −3.4 g. However, lean and fat mass and %fat differed by 4.6%–7.7% with biases of +463 g, −496 g, and −2.8%, respectively. In vivo comparison supported BBCP data; BMD and BMC were within ∼2%, but lean and fat mass and %fat differed from 1.6% to 4.9% with biases of +833 g, −860 g, and −1.1%. As all body composition comparisons exceeded the recommended 2%, the new densitometer was recalibrated. After recalibration, in vivo bias was lower (<0.05%) for lean and fat; −23 and −5 g, respectively. Similarly, BBCP lean and fat agreement improved.In conclusion, the BBCP behaves similarly, but not identical, to human in vivo measurements for densitometer cross-calibration. Spine phantoms, despite good BMD and BMC agreement, did not detect substantial lean and fat differences observed using BBCP and in vivo assessments. Consequently, spine phantoms are inadequate for dual-energy X-ray absorptiometry whole body composition cross-calibration.

Bone densitometry by dual‐energy X‐ray absorptiometry (DXA) in preterm newborns compared with full‐term peers in the first six months of life

ObjectivesTo longitudinally assess bone mineral content (BMC), bone mineral density (BMD), and whole‐body lean mass obtained through bone densitometry by dual‐energy X‐ray absorptiometry (DXA) in preterm newborns (PTNs) and compare them with full‐term newborns (FTNs) from birth to 6 months of corrected postnatal age. MethodsA total of 28 adequate for gestational age (AGA) newborns were studied: 14 preterm and 14 full‐term newborns. DXA was used to determine BMC, BMD, and lean mass in three moments: 40 weeks corrected post‐conceptual age, as well as 3 and 6 months of corrected postnatal age. PTNs had gestational age ≤ 32 weeks at birth and were fed their mother's own milk or milk from the human milk bank. ResultsAll infants had an increase in BMC, BMD, and lean body mass values during the study. PTNs had lower BMC, BMD, and lean mass at 40 weeks of corrected post‐conceptual age in relation to FTNs (p<0.001, p<0.001, p=0.047, respectively). However, there was an acceleration in the mineralization process of PTNs, which was sufficient to achieve the normal values of FTNs at 6 months of corrected age. ConclusionsThis study suggests that bone densitometry by dual‐energy X‐ray absorptiometry is a good method for the assessment of body composition parameters at baseline, and at the follow‐up of these PTNs.

Anthropometric models of bone mineral content and areal bone mineral density based on the bone mineral density in childhood study.

New models describing anthropometrically adjusted normal values of bone mineral density and content in children have been created for the various measurement sites. The inclusion of multiple explanatory variables in the models provides the opportunity to calculate Z-scores that are adjusted with respect to the relevant anthropometric parameters. Previous descriptions of children's bone mineral measurements by age have focused on segmenting diverse populations by race and sex without adjusting for anthropometric variables or have included the effects of a single anthropometric variable. We applied multivariate semi-metric smoothing to the various pediatric bone-measurement sites using data from the Bone Mineral Density in Childhood Study to evaluate which of sex, race, age, height, weight, percent body fat, and sexual maturity explain variations in the population's bone mineral values. By balancing high adjusted R(2) values with clinical needs, two models are examined. At the spine, whole body, whole body sub head, total hip, hip neck, and forearm sites, models were created using sex, race, age, height, and weight as well as an additional set of models containing these anthropometric variables and percent body fat. For bone mineral density, weight is more important than percent body fat, which is more important than height. For bone mineral content, the order varied by site with body fat being the weakest component. Including more anthropometrics in the model reduces the overlap of the critical groups, identified as those individuals with a Z-score below -2, from the standard sex, race, and age model. If body fat is not available, the simpler model including height and weight should be used. The inclusion of multiple explanatory variables in the models provides the opportunity to calculate Z-scores that are adjusted with respect to the relevant anthropometric parameters.

Measurement precision of body composition variables in elite wheelchair athletes, using dual-energy X-ray absorptiometry

The purpose of this study was to assess the reproducibility of body composition measurements by dual-energy X-ray absorptiometry (DXA) in 12 elite male wheelchair basketball players (age 31 ± 7 years, BMI 21 ± 2 kg/m2 and onset of disability 25 ± 9 years). Two whole body scans were performed on each participant in the supine position on the same day, using Lunar Prodigy Advance DXA (GE Lunar, Madison, WI, USA). Participants dismounted from the scanning table and were repositioned in-between the first and second scan. Whole body coefficient of variation (CV) values for bone mineral content (BMC), fat mass (FM) and soft tissue lean mass (LTM) were all <2.0%. With the exclusion of arm FM (CV = 7.8%), CV values ranged from 0.1 to 3.7% for all total body and segmental measurements of BMC, FM and LTM. The least significant change that can be attributed to the effect of treatment intervention in an individual is 1.0 kg, 1.1 kg, 0.12 kg for FM, LTM, and BMC, respectively. This information can be used to determine meaningful changes in body composition when assessed using the same methods longitudinally. Whilst there may be challenges in the correct positioning of an individual with disability that can introduce greater measurement error, DXA is a highly reproducible technique in the estimation of total and regional body composition of elite wheelchair basketball athletes.

Bone densitometry by dual-energy X-ray absorptiometry (DXA) in preterm newborns compared with full-term peers in the first six months of life

ObjectivesTo longitudinally assess bone mineral content (BMC), bone mineral density (BMD), and whole-body lean mass obtained through bone densitometry by dual-energy X-ray absorptiometry (DXA) in preterm newborns (PTNs) and compare them with full-term newborns (FTNs) from birth to 6 months of corrected postnatal age. MethodsA total of 28 adequate for gestational age (AGA) newborns were studied: 14 preterm and 14 full-term newborns. DXA was used to determine BMC, BMD, and lean mass in three moments: 40 weeks corrected post-conceptual age, as well as 3 and 6 months of corrected postnatal age. PTNs had gestational age ≤ 32 weeks at birth and were fed their mother's own milk or milk from the human milk bank. ResultsAll infants had an increase in BMC, BMD, and lean body mass values during the study. PTNs had lower BMC, BMD, and lean mass at 40 weeks of corrected post-conceptual age in relation to FTNs (p<0.001, p<0.001, p=0.047, respectively). However, there was an acceleration in the mineralization process of PTNs, which was sufficient to achieve the normal values of FTNs at 6 months of corrected age. ConclusionsThis study suggests that bone densitometry by dual-energy X-ray absorptiometry is a good method for the assessment of body composition parameters at baseline, and at the follow-up of these PTNs.

The bone tissue of children and adolescents with Down syndrome is sensitive to mechanical stress in certain skeletal locations: a 1-year physical training program study.

The systemic complications of Down syndrome (DS) attenuate the osteogenic response to physical activity in DS patients. Through an interventional study we showed the effects of physical training on development of bone mineral content (BMC) and density (BMD) as well as on quantitative bone ultrasound (QUS) parameters in individuals with DS. A total of 42 children with DS were randomly assigned to either an exercising (DS-E, n=20, age 16 ± 1.8 years) or non-exercising group (DS-NE, n=22, age 16.9 ± 1.5 years). DS-E group was assigned to a program of osteogenic activities with 60 min sessions twice a week, over 12 month period. Bone mass measures were performed by dual X-ray absorpsiometry (DXA) at the spine and hip, and ultrasound attenuation (BUA) and velocity (SOS) assessed from the calcaneus by QUS device. All bone parameters had evolved with age, except for neck BMD. One year of training increased BMC values at lumbar spine (7%, p<.005) and total hip (10%, p<.05), and BMD values only at lumbar spine (4%, p<.05). Changes in BUA and SOS values were not evident following training. Trained individuals increased their motor skills measured through Eurofit tests. It was concluded that a program of osteogenic physical training may induce bone improvement in children with DS, but with a lower magnitude than that reported in the specialized literature for individuals without DS.

Longitudinal study of body composition in spinal cord injury patients

Background:Bone mass loss and muscle atrophy are the frequent complications occurring after spinal cord injury (SCI). The potential risks involved with these changes in the body composition have implications for the health of the SCI individual. Thus, there is a need to quantitate and monitor body composition changes accurately in an individual with SCI. Very few longitudinal studies have been reported in the literature to assess body composition and most include relatively small number of patients. The present prospective study aimed to evaluate the body composition changes longitudinally by DEXA in patients with acute SCI.Materials and Methods:Ninety five patients with acute SCI with neurological deficits were evaluated for bone mineral content (BMC), body composition [lean body mass (LBM) and fat mass] by dual-energy X-ray absorptiometry during the first year of SCI.Results:There was a significant decrease in BMC (P < 0.05) and LBM (P < 0.05) and increase in total body fat mass (TBFM) and percentage fat at infra-lesional sites. The average decrease was 14.5% in BMC in lower extremities, 20.5% loss of LBM in legs and 15.1% loss of LBM in trunk, and increase of 0.2% in fat mass in legs and 17.3% increased fat in the lower limbs at 1 year. The tetraplegic patients had significant decrease in arm BMC (P < 0.001), arm LBM (P < 0.01) and fat percentage (P < 0.01) compared to paraplegics. Patients with complete motor injury had higher values of TBFM and fat percentage, but comparable values of BMC and LBM to patients with incomplete motor injury.Conclusions:Our findings suggest that there is a marked decrease in BMC and LBM with increase in adiposity during the first year of SCI. Although these changes depend on the level and initial severity of lesions, they are also influenced by the neurological recovery after SCI.

Bone Mineral Content and Density in Obese , Overweight and Normal Weight Adolescent Boys

The aim of this study was to compare bone mineral content (BMC), bone mineral density (BMD) and bone mineral apparent density (BMAD) in obese, overweight and normal weight adolescent boys. This study included 23 obese, 19 overweight and 25 normal weight adolescents (aged 14-20 years) boys. The three groups (obese, overweight and normal weight) were matched for age and maturation index. Body composition, BMC and BMD were assessed by dual-energy X-ray absorptiometry (DXA). The expressions whole body (WB) BMC/height and WB BMD/height were used to adjust for WB bone size. BMAD was calculated for the WB. WB BMC, WB BMC/height, total hip (TH) BMD, femoral neck (FN) BMD and ultra distal (UD) radius BMD) were higher in obese and overweight boys in comparison to normal weight boys (p < 0.05). WB BMAD was lower in obese boys in comparison to overweight and normal weight boys (p < 0.05). After adjustment for either weight or lean mass, obese boys displayed lower WB BMC, WB BMC/height and WB BMD values in comparison to overweight and normal weight boys (p < 0.05). This study suggests that WB BMC, WB BMC/height and WB BMD do not adapt to the increased body weight in obese adolescent boys.

The effect of hyperbaric oxygen therapy on fracture healing in nicotinized rats.

The aim of the present study was to investigate the effect of hyperbaric oxygen therapy on fracture healing in nicotinized rats. Thirty-two rats were divided as follows: nicotinized group (1), hyperbaric oxygen group (2), nicotinized + hyperbaric oxygen group (3), and control group (4). For 28 days, nicotine was administered in Groups 1 and 3. Then, a standard shaft fracture was induced in the left femur of rats. Groups 2 and 3 underwent hyperbaric oxygen therapy for 21 days. At the end of the experiment, fracture site, left femur and whole body bone mineral content and density were measured. The radiological and histopathological scores of Group 1 were statistically significantly lower compared to Groups 2, 3 and 4, and there was no statistically significant difference between the Groups 2, 3 and 4. In a comparison between the groups, no statistically significant difference was found in terms of bone mineral content and density values measured at the fracture site, left femur and whole body. The negative effects of nicotine on fracture healing are eliminated with hyperbaric oxygen therapy, but hyperbaric oxygen alone does not cause significant changes in healing (radiologically and histopathologically).

Excess body fat negatively affects bone mass in adolescents

ObjectiveThe aim of this study was to investigate the effects of excess body fat on bone mass in overweight, obese, and extremely obese adolescents. MethodsThis study included 377 adolescents of both sexes, ages 10 to 19 y. Weight, height, body mass index (BMI), bone age, bone mineral content (BMC), and bone mineral density (BMD) were obtained by dual-energy x-ray absorptiometry. The results were adjusted for chronological age and bone age. Comparisons according to nutritional classification were performed by analysis of variance, followed by Tukey test. Linear regression models were used to explain the variation in BMD and BMC in the L1–L4 lumbar spinal region, proximal femur, and whole body in relation to BMI, lean mass, fat mass (FM), and body fat percentage (BF%), considering P < 0.05. ResultsFor all nutritional groups, average bone age was higher than chronological age. In both sexes, weight and BMI values increased from eutrophic to extremely obese groups, except for BMD and BMC, which did not differ among male adolescents, and were smaller in extremely obese than in obese female adolescents (P < 0.01). Significant differences were observed for FM and BF% values among all nutritional groups (P < 0.01). Positive, moderate to strong correlations were detected between BMD and BMC for BMI, lean mass, and FM. A negative and moderate correlation was found between BMC and BF%, and between BMD and BF% at all bone sites analyzed in males and between BF% and spine and femur BMD, in females. ConclusionThe results reveal a negative effect of BF% on bone mass in males and indicate that the higher the BF% among overweight adolescents, the lower the BMD and BMC values.