Determination Of Bone Mineral Content Research Articles

Appendicular Muscle Mass Index as the Most Important Determinant of Bone Mineral Content and Density in Small for Gestational Age Children.

Preterm small for gestational age (SGA) children are at increased risk for low bone mineral content later in life; however, data on SGA children born at term are scarce. We included 44 SGA and 57 adequate for gestational age (AGA) children aged 6 to 11 years to compare bone mineral density (BMD) and bone mineral content (BMC) and to identify which anthropometric and biochemical values influence bone mineralization in these children. Fat mass, appendicular skeletal muscle mass index (ASMMI), BMC, and BMD were significantly lower in SGA children than in AGA (P ≤ .005). Appendicular muscle mass index correlated with BMC(TBLH,FN,L1-L4) and BMD(TBLH,FN,L1-L4) in both groups (r2 = 0.7, P < .05). In multivariate analysis, ASMMI was strongly associated with BMC and BMD in both groups. There were no differences in clinical biomarkers, calcium intake, and physical activity between the groups. Achieving adequate muscle mass contributes to adequate bone mineralization and a lower risk for low BMC and BMD in SGA children.

Comparative Analysis of CT Texture in Lumbar and Femur and Its Correlation with Bone Mineral Density and Content over Time: An Exploratory Study

Background: This research explores the application of morphometric texture analysis in chest Computed Tomography (CT) scans for determining Bone Mineral Content (BMC) and its temporal changes, both crucial in diagnosing osteoporosis. The study establishes an innovative approach to osteoporosis screening by leveraging Hounsfield Units (HUs) in CT scans to evaluate BMC, offering a comparison with dual-energy X-ray absorptiometry (DXA)-based BMC. Methods: A total of 806 instances (encompassing 379 individuals) were meticulously compiled from a sole institution, during the period stretching from 6 May 2012 to 30 June 2020. In this detailed analysis, each participant was subjected to a pair of chest CT scans, sequentially pursued by a DXA scan, spread over two years. Focused records of BMC values at the inaugural lumbar vertebra (L1) were secured from both the DXA and CT axial slices across all instances. A meticulous selection process pinpointed the largest trabecular section from the L1 vertebral body, whereupon 45 distinctive texture attributes were harvested utilizing gray-level co-occurrence matrix methodologies. Utilizing these amassed 45 attributes, a regression architecture was devised, aiming to forecast the precise BMC values individually. Moreover, an alternative regression framework was engaged, leveraging 90 distinct features, to gauge the BMC fluctuations observed between the duo of scans administered to each participant. Results: The precision of the cultivated regression frameworks was scrupulously assessed, benchmarking against the correlation coefficient (CC) and the mean absolute deviation (MAE) in comparison to the DXA-established references. The regression apparatus employed for estimating BMC unveiled a CC of 0.754 and an MAE of 1.641 (g), respectively. Conversely, the regression mechanism devoted to discerning the variations in BMC manifested a CC of 0.680, coupled with an MAE of 0.528 (g), respectively. Conclusion: The innovative methodology utilizing morphometric texture analysis in CT HUs offers an indirect, yet promising, approach for osteoporosis screening by providing estimations of BMC and its temporal changes. The estimations demonstrate moderate positive correlations with DXA measures, suggesting a potential alternative in circumstances where DXA scanning is limited.

Femoral Structure and Biomechanical Characteristics in Sanfilippo Syndrome Type-B Mice.

Sanfilippo syndrome Type-B, also known as mucopolysaccharidosis IIIB (MPS IIIB), accounts for approximately one-third of all Sanfilippo syndrome patients and is characterized by a similar natural history as Type-A. Patients suffer from developmental regression, bone malformation, organomegaly, GI distress, and profound neurological deficits. Despite human trials of enzyme replacement therapy (ERT) (SBC-103, AX250) in MPS IIIB, there is currently no FDA approved treatment and a few palliative options. The major concerns of ERT and gene therapy for the treatment of bone malformation are the inadequate biodistribution of the missing enzyme, N-acetyl-α-glucosaminidase (NAGLU), and that the skeleton is a poorly hit target tissue in ERT and gene therapy. Each of the four known human types of MPS III (A, B, C, and D) is usually regarded as having mild bone manifestations, yet it remains poorly characterized. This study aimed to determine bone mineral content (BMC), volumetric bone mineral density (vBMD), and biomechanical properties in femurs MPS IIIB C57BL/6 mice compared to phenotypic control C57BL/6 mice. Significant differences were observed in MPS IIIB mice within various cortical and cancellous bone parameters for both males and females (p < 0.05). Here, we establish some osteogenic manifestations of MPS IIIB within the mouse model by radiographic and biomechanical tests, which are also differentially affected by age and sex. This suggests that some skeletal features of the MPS IIIB mouse model may be used as biomarkers of peripheral disease correction for preclinical treatment of MPS IIIB.

Determinants of bone mass in older adults with normal- and overweight derived from the crosstalk with muscle and adipose tissue

Lower bone mass in older adults may be mediated by the endocrine crosstalk between muscle, adipose tissue and bone. In 150 community-dwelling adults (59–86 years, BMI 17–37 kg/m2; 58.7% female), skeletal muscle mass index, adipose tissue and fat mass index (FMI) were determined. Levels of myokines, adipokines, osteokines, inflammation markers and insulin were measured as potential determinants of bone mineral content (BMC) and density (BMD). FMI was negatively associated with BMC and BMD after adjustment for mechanical loading effects of body weight (r-values between −0.37 and −0.71, all p < 0.05). Higher FMI was associated with higher leptin levels in both sexes, with higher hsCRP in women and with lower adiponectin levels in men. In addition to weight and FMI, sclerostin, osteocalcin, leptin × sex and adiponectin were independent predictors of BMC in a stepwise multiple regression analysis. Muscle mass, but not myokines, showed positive correlations with bone parameters that were weakened after adjusting for body weight (r-values between 0.27 and 0.58, all p < 0.01). Whereas the anabolic effect of muscle mass on bone in older adults may be partly explained by mechanical loading, the adverse effect of obesity on bone is possibly mediated by low-grade inflammation, higher leptin and lower adiponectin levels.

MO055STABLE CALCIUM ISOTOPES: A NOVEL BIOMARKER OF BONE MINERAL CONTENT IN PATIENTS WITH CHRONIC KIDNEY DISEASE

Abstract Background and Aims In CKD dysregulated calcium (Ca) homeostasis is common and causally associated with reduced bone mineral density (BMD) and vascular calcification. Currently available radiological measures and biomarkers do not allow accurate evaluation of BMD. The aim of our study was to determine the sensitivity and specificity of stable Ca isotopes in determining bone mineral content. Method We measured stable Ca isotopes 44Ca and 42Ca by plasma-ionization mass-spectrometry in blood and urine. The relationship between bone Ca gain and loss is calculated using a compartment model based on Ca kinetics, and expressed as δ44/42Ca. Ca absorption from bones increases δ44/42CaBlood and δ44/42CaUrine, and resorption decreases these fractions. 104 children in CKD4-5 and on dialysis (CKD4-5D), 40 matched controls and 100 adults underwent Ca isotope measurement, bone biomarkers, dual energy x-ray absorptiometry (DXA) and tibial peripheral quantitative CT scan (pQCT), an accurate measure of cortical BMD. Results In healthy children the δ44/42CaBlood and δ44/42CaUrine were higher than in adults (p&amp;lt;0.0001), reflecting avid Ca uptake during bone formation. Since urinary Ca excretion is impaired in CKD, δ44/42CaBlood was higher and δ44/42CaUrine lower in children with CKD4-5D compared to controls (p&amp;lt;0.001 for both); Figure 1. In CKD2-5D δ44/42CaBlood positively correlated with cholecalciferol (p=0.01) and alfacalcidol (p=0.002) doses, implying increased bone Ca uptake when Ca bioavailability is increased. δ44/42CaBlood positively correlated with biomarkers of bone formation (alkaline phosphatase, p=0.05) and negatively with bone resorption markers (PTH, p=0.013; TRAP5b, p&amp;lt;0.001 and CTX, p=0.006). δ44/42CaBlood positively correlated with tibial cortical BMD-Z-score (p=0.006, R2=0.39), and DXA hip BMD-Z-score (p=0.02). On multivariable linear regression analysis significant and independent predictors of tibial cortical BMD-Z-score were δ44/42CaBlood (β=0.68, p=0.006) and PTH (β-0.39, p=0.04), together predicting 67% of the variability in BMD. Conclusion Ca isotope ratios provide a novel, non-invasive method of assessing bone mineralization. Further studies are in progress to define optimal levels of δ44/42CaBlood that can guide safe and effective treatment to prevent Ca deficiency or overload.

86 Skeletal response to whole body vibration and dietary calcium and phosphorus in growing pigs

Abstract Whole body vibration (WBV) is reported to elicit increased bone mass and strength. This experiment was designed to determine the effects of whole body vibration (WBV) and dietary calcium (Ca) and phosphorus (P) on bone microarchitecture and turnover. A total of 26 growing pigs were utilized in a 60-d experiment. Pigs were randomly assigned within group to a 2 × 2 factorial with Ca and P concentration (low and adequate) and WBV. Low Ca, P diets were 0.9 g/kg less than recommended levels of Ca and available P. Pigs receiving WBV were vibrated 30 min/d, 3 d/wk at a magnitude of 1-2mm and frequency of 50 Hz. On d 0, 30, and 60, digital radiographs were taken to determine bone mineral content by radiographic bone aluminum equivalency (RBAE) and blood was collected for bone formation biomarker (osteocalcin, OC) and bone resorption biomarker (carboxy-terminal collagen crosslinks, CTX-I). At d 60, pigs were harvested and the left third metacarpal bone was excised for analysis by micro computed tomography (microCT) to measure trabecular microarchitecture and cortical bone geometry. Maximum RBAE values for the medial or lateral cortices were not affected (P &gt; 0.05) by WBV. Pigs fed adequate Ca and P tended (P = 0.10) to have increased RBAE max values for the medial and lateral cortices. Vibrated pigs had decreased CTX-1 concentrations (P = 0.044). Pigs fed decreased Ca and P had increased (P &lt; 0.05) concentrations of OC. Vibrated pigs had lower trabecular number (P = 0.002) and increased trabecular separation (P = 0.003), whereas cortical bone parameters were not changed by WBV or diet (P &gt; 0.05). Whole body vibration in this study did not elicit an osteogenic response; however, early indications of bone turnover were observed.

Skeletal response to whole body vibration and dietary calcium and phosphorus in growing pigs.

The quality and strength of the skeleton is regulated by mechanical loading and adequate mineral intake of calcium (Ca) and phosphorus (P). Whole body vibration (WBV) has been shown to elicit adaptive responses in the skeleton, such as increased bone mass and strength. This experiment was designed to determine the effects of WBV and dietary Ca and P on bone microarchitecture and turnover. A total of 26 growing pigs were utilized in a 60-d experiment. Pigs were randomly assigned within group to a 2 × 2 factorial design with dietary Ca and P concentration (low and adequate) as well as WBV. The adequate diet was formulated to meet all nutritional needs according to the NRC recommendations for growing pigs. Low Ca, P diets had 0.16% lower Ca and 0.13% lower P than the adequate diet. Pigs receiving WBV were vibrated 30 min/d, 3 d/wk at a magnitude of 1 to 2 mm and a frequency of 50 Hz. On days 0, 30, and 60, digital radiographs were taken to determine bone mineral content by radiographic bone aluminum equivalency (RBAE) and serum was collected to measure biochemical markers of bone formation (osteocalcin, OC) and bone resorption (carboxy-terminal collagen crosslinks, CTX-I). At day 60, pigs were euthanized and the left third metacarpal bone was excised for detailed analysis by microcomputed tomography (microCT) to measure trabecular microarchitecture and cortical bone geometry. Maximum RBAE values for the medial or lateral cortices were not affected (P > 0.05) by WBV. Pigs fed adequate Ca and P tended (P = 0.10) to have increased RBAE max values for the medial and lateral cortices. WBV pigs had significantly decreased serum CTX-1 concentrations (P = 0.044), whereas animals fed a low Ca and P diet had increased (P < 0.05) OC concentrations. In bone, WBV pigs showed a significantly lower trabecular number (P = 0.002) and increased trabecular separation (P = 0.003), whereas cortical bone parameters were not significantly altered by WBV or diet (P > 0.05). In summary, this study confirmed the normal physiological responses of the skeleton to a low Ca, P diet. Interestingly, although the WBV protocol utilized in this study did not elicit any significant osteogenic response, decreases in CTX-1 in response to WBV may have been an early local adaptive bone response. We interpret these data to suggest that the frequency and amplitude of WBV was likely sufficient to elicit a bone remodeling response, but the duration of the study may not have captured the full extent of an entire bone remodeling cycle.

Caloric Intake Affects Neonatal Bone Development and Energy Metabolism

Deficits in bone deposition during early‐life increases risk of osteoporosis later in life. Bone marrow mesenchymal stem cells (MSC) are a subset of multipotent stem cells residing within the bone which provide the life‐long supply of bone forming cells. Our previous work has revealed that the activity and differentiation potential of MSC are subject to alteration based on neonatal nutrition. With increasing interest in metabolic disorders and an increasing incidence of bone diseases, we aimed to elucidate the impact of dietary energy restriction and excess on the activity and differentiation potential of MSC during neonatal development. During a 16‐day study, 30 neonatal pigs (24±6h old) were fed with milk replacers that were isonitrogenous, but either 25% restricted (R), adequate (A), or 25% in excess (E) of energy requirements through the adjustment of dietary fat and lactose levels. Piglets were fed 8 times/d at a rate to match the growth rate of sow‐reared piglets. Body weight and feed intake were recorded daily. At the end of the study, humeri were collected for the isolation of MSC and radial/ulna bones were collected for physical measurement and determination of bone mineral content. Fat and liver tissues were collected for gene expression analysis. Dietary energy level did not impact body weight (BW) during the study (4.40±0.35 kg final BW). The energy restricted group had 7.5% greater bone mineral content than the E group (R: 37.66±0.36, A: 35.56±0.41, E: 35.02±0.41. P&lt;0.05), but bone cross‐sectional area was not different between treatments. No difference was found in both in vivo and in vitro MSC proliferation as determined by BrDU labeling and EDU straining respectively. Assays to examine the in vitro differentiation potential of the MSC, suggested that MSC isolated from the R piglets were more primed towards an osteogenic lineage than those from the other treatments, and this was featured by greater expression of osteocalcin and fibronectin (P&lt;0.05). However, no difference in adipocytic differentiation potential was seen based on dietary treatment. Gene expression analysis in subcutaneous fat suggests that excess energy diet promoted lipogenesis via the increased expression of fatty acid synthesis (FAS) and acyl‐CoA carboxylase (ACC). In the liver, excess energy increased the expression of carnitine palmitoyltransferae I (CPT1), peroxisome proliferator‐activated receptor alpha (PPARα), and oxidative stress responsive kinase I (OXSR1), glutathione peroxidase 3 (GPX3) but decreased the expression of FAS. These data suggested that excessive energy consumption during the neonatal period may compromise bone integrity, will promote lipid accumulation in subcutaneous fat, and will induce oxidative stress.Support or Funding InformationThe project is funded by USDA with the access number: 2015‐67015‐25094.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Dietary Calcium and Phosphate levels affect bone development and mesenchymal stem cell lineage allocation in neonatal pigs

Deficits in bone deposition during early‐life have been associated with increased risk of osteoporosis later in life. Bone marrow mesenchymal stem cells (MSC) are a subset of multipotent stem cells residing within the bone which provide the life‐long supply of bone forming cells. Molecular mechanisms affecting the activity and differentiation potential of MSC are still poorly understood. Our previous work has revealed that the activity and differentiation potential of MSC are subject to alteration based on neonatal nutrition. Dietary calcium (Ca) and phosphate (PO4) levels play a critical role in regulation of bone development. With increasing interest in MSC therapies and an increasing incidence of bone diseases, we aimed to elucidate the impact of marginal dietary Ca and PO4 deficiency and excess on the activity and differentiation potential of MSC during neonatal development. During a 16‐day study, 27 neonatal pigs (n= 27, 24±6h old) were fed milk replacers that were isonitrogenous and isocaloric, but either 25% deficient (D), adequate (A), or 25% in excess (E) of Ca and PO4 requirements. Piglets were fed 8 times/d at a rate to match the growth rate of sow‐reared piglets. Body weight and feed intake were recorded daily. Blood was collected on d8 and d16 for analysis. Humeri were collected for the isolation of MSC and radial/ulna bones were collected for physical measurement and determination of bone mineral content. Serum PO4 concentrations were significantly higher in the A group compared to the D group on day 8, however at day 16 the D group had the highest serum PO4 concentrations with the E group having the lowest PO4 concentrations (P&lt;0.05). Serum FGF23 was greater in the D group than the E group at 16d (77.21±1.90 pg/mL vs. 70.38±1.90 pg/mL, P&lt;0.05), with values for the A group being intermediate to these groups. The D group had lower bone mineral content and bone volume as compared to the E group. Among the MSC, those isolated from D pigs had significantly lower rates of in vivo proliferation of than those isolated from A pigs, as determined by BrdU labelling (0.063±0.007 vs. 0.089±0.007), but significantly higher in vitro proliferation than those isolated from E pigs at both 12 and 24 h post‐plating (12 h: 0.40 ±0.04 vs 0.23±0.04; 24h: 0.28±0.04 vs 0.10±004). Ca and PO4 deficiency appears, based on the gene expression of key adipogenic factors as well as cellular accumulation of neutral lipids, to have predisposed MSC towards adipogenic differentiation. MSC from D pigs had increased expression of PPARγ2, FABP4, and LPL (P&lt;0.05) and greater accumulation of neutral lipids as indicated by Oil Red O staining. Coupled with this apparent predisposition for adipocytic differentiation, a decrease in osteogenic capabilities were seen among MSC isolated from D pigs. This was determined based on reduced expression of the osteogenic regulators osteocalcin and fibronectin at d6 post differentiation. These findings demonstrated that even minor dietary deficiencies of Ca and PO4 during the neonatal period can have a profound impact on bone development. These dietary deficiencies may also program future bone health by altering the differentiation capabilities of MSC.Support or Funding InformationThis project is support by USDA grantThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Usefulness of Reflection Scanning in Determining Whole-Body Composition in Broadly Built Individuals Using Dual-Energy X-ray Absorptiometry

Whole-body composition analysis by dual-energy X-ray absorptiometry (DXA) requires subjects to fit within the width limits of the DXA bed. To overcome this limitation, the aim of this study was to validate a partial scanning technique at which the upper left limb is deliberately left unscanned and measurements are “reflected” from the right-side upper limb. A Hologic Explorer-W densitometer was used in a sample of 189 participants, including athletes and nonathletes, ranging from underweight to obese (body mass index: 17.0–40.1 kg/m2). A whole-body scan was analyzed as the reference procedure to determine bone mineral content (BMC), lean soft tissue (LST), and fat mass (FM), and reanalyzed using a partial reflection scanning (RS) technique. RS estimates of BMC were associated with athletic status and differed significantly from reference estimates (p < 0.05). Also, the RS estimates of LST and FM were different (p < 0.05) from those of the reference whole-body scan, although differences were small (0.17 kg, −0.02 kg, and −0.10% for BMC, LST, and FM, respectively). The alternative procedure explained more than 99% of the reference scan variance with low limits of agreement (BMC: −13.8 to 23.9 g [athletes] and −6.3 to 18.0 g [nonathletes]; LST: −0.11 to 0.45 kg; FM: −0.22 to 0.17 kg). Regardless of body mass index, athletic status, and gender, RS is a useful and simple solution to be used in individuals wider than the DXA scan area. However, individual errors for BMC may be higher in athletes engaged in lateral dominant sports practice.

Vitamin D status and physical activity interact to improve bone mass in adolescents. The HELENA Study

The effects of vitamin D concentrations on bone mineral content in adolescents are still unclear. Vitamin D and physical activity (PA) may interact to determine bone mineral content (BMC) in two possible directions; 25(OH)D sufficiency levels improve BMC only in active adolescents, or PA increases BMC in individuals with replete vitamin D levels. The effects of suboptimal 25-hydroxycholecalciferol (25(OH)D) concentrations on BMC in adolescents are still unclear. The main aim of this study was to evaluate the influence of 25(OH)D on BMC in adolescents, considering the effect of body composition, sex, age, Tanner stage, season, calcium and vitamin D intakes, physical fitness and PA. Serum 25(OH)D concentrations, anthropometric measurements, dual energy X-ray absorptiometry measurements, calcium and vitamin D intakes, PA and physical fitness were obtained in 100 Spanish adolescents (47 males), aged 12.5-17.5years, within the framework of the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study. Relations were examined using ANCOVA and regression analyses including BMC as dependent variable. Linear regression of BMC suggested that 25(OH)D concentrations independently influenced total and leg BMC after controlling for age, sex, lean mass, seasonality and calcium intake (B = 0.328, p < 0.05, and B = 0.221, p < 0.05, respectively) in the physically active group. No significant influence of 25(OH)D concentrations on BMC was observed in the inactive group. Significant effect was shown between the interaction of 25(OH)D and PA on BMC for the total body and legs (both p < 0.05). Vitamin D and PA may interact to determine BMC. 25(OH)D sufficiency levels improve bone mass only in active adolescents, or PA has a positive influence on BMC in individuals with replete vitamin D levels.

Determinants of bone mineral content and bone area in Indian preschool children

The objective of this study was to examine the lifestyle factors that influence total body bone mineral content (TB BMC) and total body bone area (TB BA) in Indian preschool children. TB BMC and TB BA were measured by dual-energy X-ray absorptiometry (Lunar DPX PRO) in 71 apparently healthy children aged 2-3years. A fasting blood sample was analyzed for serum concentrations of ionized calcium (iCa), intact parathyroid hormone (iPTH), phosphorus (iP) and 25-hydroxyvitamin D(3) (25 OHD). Dietary intake of energy, protein, calcium and phosphorus was estimated from a 3-day diet recall. The daily physical activity and sunlight exposure were recorded by a questionnaire. The study children were shorter than their age-gender matched WHO counterparts with a mean height for age Z score of -1.3±1.5. The mean dietary intake of calcium was 46% of the Indian recommended dietary intakes (RDI). Seventy-three percent of children had low iCa concentrations, and 57% were deficient in vitamin D. Generalized linear model analysis revealed that height, lean body mass, weight, activity, sunlight exposure in minutes and dietary intakes of calcium, zinc and iron were the significantly influencing factors (p<0.05) of TB BMC and TB BA. In conclusion, attaining optimal height for age, achieving the goals of overall nutrition with adequate calcium, iron and zinc intakes as well as adequate physical activity and sunlight exposure play an important role in achieving better TB BMC and TB BA in preschool children.

Consumption of Green Tea Extract Results in Osteopenia in Growing Male Mice , ,

Consumption of green tea may reduce body weight gain. Although many disorders are related to obesity, bone mass is positively correlated with body mass. Therefore, our purpose in this study was to determine the effects of green tea extract (GTE) on bone mass and architecture in rapidly growing lean [C57BL/6 wild type (WT)] and genetically obese, leptin-deficient (ob/ob) male mice. Five-week-old lean and ob/ob mice were assigned to diets containing GTE at 0, 1, or 2% for 6 wk. Femoral and lumbar vertebral bone volume and architecture were evaluated by micro-computed tomography (μCT). Following μCT analysis, femora were ashed to determine bone mineral content and density. Compared with WT mice, ob/ob mice had shorter femora (P < 0.001), lower femoral bone volume (P < 0.001), and lower femoral bone mineral content (P < 0.001), but higher cancellous bone volume in lumbar vertebrae (P < 001). Neither genotype nor treatment affected femoral bone mineral density, indicating normal mineralization. GTE consumption resulted in lower femur length, volume, mineral content, cortical volume, and cortical thickness (P < 0.001), as well as lower cancellous bone volume/tissue volume (P < 0.008) and trabecular thickness (P < 0.004) in lumbar vertebrae. The results indicate that leptin is not essential for the reduced gains in body weight and bone mass due to GTE in growing mice and suggest that consumption of large quantities of green tea may reduce the rate of bone accumulation during growth.

Metabolic bone disease in HIV infection

HIV mainly replicates in CD4þ T lymphocytes andmonocyte/macrophages causing severe immunologicalimpairment. In addition to the immune system, HIVinfection affects tissues and organs such as kidney, liver,the central nervous system, heart and bone showing acomplex pathogenesis [1].The advent and widespread use of highly activeantiretroviral therapy (HAART) in the last two decadeshasled toa markedimprovementinthe treatmentofHIVdisease even though viral infection cannot be eradicatedbecause HAART does not completely eliminate the viralreservoirs [2]. HAART has dramatically changed thecourseofHIVinfection froma fatalinfectiontoachronicand relatively manageable disease. The increased lifeexpectancyofHIVpatientsandtheeffectsofHAARThavechanged the management of HIV infection. Nowadaysmedical treatment is no longer focused solely on HIVinfection, opportunistic diseases and monitoring immunederangement, but also includes the control of metabolic,cardiovascular, liver, bone and kidney complications. Inparticular, bone alterations have been observed in thecourse of HIV disease representing a pivotal clinicalprobleminthemanagementofHIVpatientsespeciallyforapossible development of bone fractures [3]. The majorbonelesionsdetectableinHIVpatientsarerelatedtobonedemineralization (osteopenia/osteoporosis and osteoma-lacia) and osteonecrosis ([4] for a review).This report will discuss the pathogenesis, diagnosis andtreatment of major bone complications represented bybone demineralization diseases during HIV infection andHAART treatment.

Cigarette Smoking, Birthweight and Osteoporosis in Adulthood: Results from the Hertfordshire Cohort Study

We looked for interaction between early environment and adult lifestyle in determination of bone mineral content (BMC) and bone mineral density (BMD) among 498 men and 468 women for whom birth records were available. Participants completed a health questionnaire, and bone densitometry (DXA) of the lumbar spine and femoral neck performed.We found no relationships between cigarette and alcohol consumption, physical activity and either BMC or BMD after adjustment for age, body mass index, dietary calcium, social class, HRT use and years since menopause. However, male current smokers in the lowest third of birth weight had lower femoral neck BMD than ex- or never smokers from the lowest birth weight third (p value for interaction term = 0.04). Similar trends were seen with femoral neck BMC and lumber spine BMC.Individuals of lower birth weight may be particularly vulnerable to the effects of bone noxious stimuli such as cigarette smoking.

Early life and current determinants of bone in South African children of mixed ancestral origin

Background: The influence of early life factors on the bone mineral density of children has been identified, however the contribution of these determinants may vary.Aim: The study investigated determinants of bone mineral content (BMC) in South African children of mixed ancestral origin.Subjects and methods: Early life data including birth weight, maternal alcohol consumption and smoking during pregnancy were collected on 9-year-old children of mixed ancestral origin (n = 64). Grip strength was measured, and physical activity, housing density and dietary data were collected. Whole body BMC (WB BMC), fat-free soft tissue and fat tissue were measured using dual energy X-ray absorptiometry.Results: Maternal alcohol consumption during pregnancy was associated with WB BMC, however after adjusting for possible confounders, this was no longer significant. When combined with gender, gestational age and maternal BMC in a multiple regression, maternal alcohol consumption during pregnancy could explain 20% of the variance in the WB BMC, however when current height was included in the model, the contribution of the other factors was insignificant. There was however a significant correlation between current height and birth weight (r = 0.34; p < 0.01) and alcohol consumption during pregnancy (r = 0.34; p < 0.05). A model consisting of current factors such as age, weight, gender, grip strength and calcium intake was able to explain 81.5% of the variance. Housing density was negatively correlated with WB BMC (r =–0.11; p = 0.05).Conclusion: These data suggest that although early life factors may contribute indirectly to the bone mass of children of mixed ancestral origin, the contribution of current factors is greater. In addition, environmental factors such as housing density have a direct effect on bone mass, independent of body size.

Dual Energy X-Ray Absorptiometry-Based Assessment of Male Patients Using Standardized Bone Density Values and a National Reference Database

Dual energy X-ray absorptiometry (DXA) measurements from different manufacturers provide different bone mineral density (BMD) values and derived T-scores and Z-scores. These differences result partly from technical differences in the algorithms for the determination of bone mineral content and bone area and partly from the use of different manufacturer-derived reference databases. The present study was to implement a uniform expression of BMD in all male patients by using standardized BMD (sBMD) values and referring to a newly established national male reference sample. In 8 bone densitometry centers throughout Belgium 229 young healthy men were measured on Hologic (Bedford, MA) or GE-Lunar (Madison, WI) bone densitometers. Quality control procedures were implemented and site cross-calibration performed using the European Spine Phantom. Absolute BMD values were converted to standardized values by validated formulas (sBMD). Clinically acceptable between-center differences were noted. No discrepancy was observed in terms of mean sBMD and standard deviations at the lumbar spine and proximal femur between the Belgian and the US reference populations. Region-specific sBMD thresholds for the diagnosis of male osteoporosis were calculated. The current data provide a basis to implement a nation-wide, uniform expression of BMD in male patients and allow harmonization of the BMD-based diagnosis and treatment of osteoporosis in men.

Is significant cystic fibrosis‐related liver disease a risk factor in the development of bone mineralization abnormalities?

In order to assess the effects of significant cystic fibrosis-related liver disease (CFLD) on bone health, we compared the bone mineral status of older children and adolescents with CFLD to those with cystic fibrosis (CF) alone. Thirteen children (age range, 10-19 years) from our clinical CF services were identified with significant CFLD (9 of these 13 patients had clinical and radiological evidence of portal hypertension). This cohort was then matched by age, gender, and anthropometric measurements with equal numbers of patients with CF alone. All patients had a dual-energy X-ray absorptiometry (DEXA) scan to determine bone mineral content (BMC), bone area (BA), bone mineral density (BMD), and bone mineral apparent density (BMAD) in the region of the lumbar spine. Blood was drawn to determine serum vitamin A, D, E, and K status and liver function tests. The best forced expired volume in 1 sec (FEV1) for each patient in the 12 months around the time of the scan was also documented. Patients with CFLD had slightly worse FEV1 (82 +/- 20% vs. 91 +/- 16%, P = 0.05) and significantly higher alanine aminotransferase (65.5 +/- 35 IU/l vs. 30 +/- 20 IU/l, P = 0.01) than those with CF alone. The mean lumbar spine BA, BMC, BMD, and BMAD were not different between children with CFLD and CF. In conclusion, the presence of significant liver disease in children with CF does not appear to be an additional risk factor for the development of abnormal bone mineralization.

Muscle strength is a determinant of bone mineral content in the hemiparetic upper extremity: Implications for stroke rehabilitation

Individuals with stroke have a high incidence of bone fractures and approximately 30% of these fractures occur in the upper extremity. The high risk of falls and the decline in bone and muscle health make the chronic stroke population particularly prone to upper extremity fractures. This was the first study to investigate the bone mineral content (BMC), bone mineral density (BMD), and soft tissue composition of the upper extremities and their relationship to stroke-related impairments in ambulatory individuals with chronic stroke (onset >1 year). Dual-energy X-ray absorptiometry (DXA) was used to acquire total body scans on 56 (22 women) community-dwelling individuals (≥50 years of age) with chronic stroke. BMC (g) and BMD (g/cm 2), lean mass (g), and fat mass (g) for each arm were derived from the total body scans. The paretic upper extremity was evaluated for muscle strength (hand-held dynamometry), impairment of motor function (Fugl–Meyer motor assessment), spasticity (Modified Ashworth Scale), and amount of use of the paretic arm in daily activities (Motor Activity Log). Results showed that the paretic arm had significantly lower BMC (13.8%, P < 0.001), BMD (4.5%, P < 0.001), and lean mass (9.0%, P < 0.001) but higher fat mass (6.3%, P = 0.028) than the non-paretic arm. Multiple regression analysis showed that lean mass in the paretic arm, height, and muscle strength were significant predictors ( R 2 = 0.810, P < 0.001) of the paretic arm BMC. Height, muscle strength, and gender were significant predictors ( R 2 = 0.822, P < 0.001) of lean mass in the paretic arm. These results highlight the potential of muscle strengthening to promote bone health of the paretic arm in individuals with chronic stroke.

Validation of fan beam dual energy x ray absorptiometry for body composition assessment in adults aged 18–45 years

Background: Pencil beam dual energy x ray absorptiometry (DXA) has been shown to provide valid estimates of body fat (%BF), but DXA fan beam technology has not been adequately tested...