Decrease In Bone Mineral Content Research Articles

Effect of 2-6 weeks of systemic steroids on bone mineral density in children.

Background The use of systemic steroids for 6+ weeks in children is associated with decreased bone mineral content (BMC) and density (BMD). However, the effects of a shorter duration of use on BMD are unknown.Purpose To determine the effect of the use of systemic steroids for 2–6 weeks on BMD and BMC in pediatric patients.Methods Twenty-five pediatric patients (21 with tuberculosis, 2 with systemic juvenile idiopathic arthritis, 1 with inflammatory bowel disease, 1 with autoimmune hemolytic anemia) who received systemic steroids for 2–6 weeks and 25 age- and sexmatched controls were enrolled. BMC, BMD, and z scores of the whole body (WB), lumbar spine (LS), nondominant distal radius (DR), and total body less the head (TBLH) were determined by dual-energy x-ray absorptiometry at baseline, the end of steroid therapy or 6 weeks (whichever was earlier; first follow-up), and at the end of 3 months from baseline (second follow-up) in patients and at baseline in controls. The values were adjusted for confounding variables. Continuous and categorical variables were compared using Student t test and the chi-square test or Fisher exact test, respectively. Pairwise comparisons employed Bonferroni correction.Results Statistically significant decreases in BMC, BMD, and all z scores were observed. BMC declined by 5.37%, 2.08%, 1.82%, and 2.27%, and 11.42%, 3.75%, 3.34%, and 4.17% for WB, LS, DR, and TBLH, respectively, at the first and second follow-ups, respectively. Similarly, BMD declined by 2.01%, 2.31%, 2.18%, and 1.70% and 4.59%, 3.76%, 3.14%, and 3.50% for the WB, LS, DR, and TBLH, respectively, at the first and second follow-ups, respectively. A significant negative correlation was found among bone densitometric parameters, duration, and cumulative dose.Conclusion The use of systemic steroids for 2–6 weeks in pediatric patients decreased the BMD and BMC of trabecular and cortical bones, an effect that persisted after discontinuation.

Prognostic impacts of glucocorticoid treatment in patients with polymyalgia rheumatica and giant cell arteritis

Identifying comorbidities in polymyalgia rheumatica/giant cell arteritis (PMR/GCA) is crucial for patients’ outcomes. The present study aimed to evaluate the impact of the inflammatory process and glucocorticoid treatment on aortic arterial stiffness and body composition in PMR/GCA. 77 patients with newly diagnosed PMR/GCA were treated with oral glucocorticoids and followed for 40 weeks. Aortic pulse wave velocity (PWV) was measured at baseline and during the follow-up period and compared to the results of temporal artery biopsy (TAB) and 18F-FDG PET/CT. Body composition was assessed by total body DXA at baseline and the end of the study. Of 77 patients (49 (63.6%) female, mean of age: (71.8 ± 8.0)), 64 (83.1%) had pure PMR, 10 (13.0%) concomitant PMR and GCA, and 3 (3.9%) pure GCA. Compared to baseline values, aortic PWV was initially decreased at week 16 (p = 0.010) and remained lower than baseline at week 28 (p = 0.002) and week 40 (p < 0.001), with no association with results of TAB and 18F-FDG PET/CT. Aortic PWV was significantly associated with age, male gender, left systolic and diastolic blood pressure, right diastolic blood pressure, and CRP. Total bone mineral content (BMC) was decreased in both genders (p < 0.001), while fat mass (FM) was significantly increased (p < 0.001). However, lean body mass did not significantly change during the study. Changes in FM were correlated with cumulative prednisolone dose (rho: 0.26, p = 0.031). Glucocorticoid treatment of patients with PMR/GCA had several prognostic impacts. Arterial stiffness was decreased due either to the treatment or a reduction in the inflammatory load. Additionally, treatment led to changes in body composition, including a decrease in BMC and FM excess.

2261. Phosphaturia in HIV-Exposed Uninfected Neonates Associated With Maternal Use of Tenofovir Disoproxil Fumarate in Late Pregnancy

BackgroundOur recent study showed significantly lower bone mineral content (BMC) in HIV-exposed uninfected (HEU) neonates born to HIV-infected (HIV+) mothers who took tenofovir disoproxil fumarate (TDF) in late pregnancy compared with no TDF use. In this cohort we sought to understand possible mechanisms for lower BMC by comparing markers of bone metabolism and renal function with TDF exposure in HEU neonates.MethodsAmong a subset of HEU children in the multicenter (United States and Puerto Rico) observational Surveillance Monitoring for ART Toxicities (SMARTT) Cohort study, we enrolled neonates (≥36 weeks gestational age) of HIV+ mothers who took TDF for ≥8 weeks in the third trimester (TDF+) or no TDF in pregnancy (TDF-). In addition to BMC measures, we collected a blood and urine sample on each child ≤30 days of birth to measure serum creatinine, phosphate, 25-OH vitamin D, parathyroid hormone and urine creatinine, phosphate and N-terminal telopeptide. Standard equations were used to estimate proximal tubular phosphate reabsorption and glomerular filtration rate (eGFR). Comparisons were made by TDF exposure using Wilcoxon and Fisher’s exact tests. We fit linear models to compare TDF+ and TDF− for each assay by age in days at sample collection (slope), stratified by age group at sample collection time (0–3 days, 4–30 days).ResultsOf 160 HEU neonates (Black 71%, Hispanic 31%), 82 were TDF+ and 78 TDF−. Sociodemographic and anthropometric characteristics did not differ by TDF exposure in each age group. Within 0–3 days of life, TDF+ had a greater decline in serum creatinine (P = 0.04) and a greater increase in eGFR compared with TDF− (P = 0.06), but no difference in slope by TDF exposure within 4–30 days of life, nor in serum phosphate in either age group. Proximal tubular phosphate reabsorption was similar for both groups within the first 3 days of life, with a significantly greater decline in phosphate reabsorption between 4 and 30 days of life in the TDF+ compared with the TDF− group (P = 0.006, Figure 1). Bone markers did not differ by TDF exposure for either age group.ConclusionUrinary phosphate loss was increased among HEU neonates of mothers who took TDF in late pregnancy. This suggests proximal tubular dysfunction and may explain, at least in part, the decrease in BMC previously described. Disclosures R. Van Dyke, Giliad Sciences: Grant Investigator, Research grant.

Low Muscle Strength and Mass Is Associated With the Accelerated Decline of Bone Microarchitecture at the Distal Radius in Older Men: the Prospective STRAMBO Study

Low muscle mass and strength are associated with poor bone microarchitecture. We studied the association of muscle mass and strength with changes in bone microarchitecture of distal radius in 821 older men during an 8-year prospective follow-up. Bone microarchitecture was assessed by high resolution peripheral quantitative computed tomography (XtremeCT-1, Scanco) at baseline, then after 4 and 8 years. Relative appendicular lean mass of the upper limbs (RALM-u.l.) was calculated as DXA-measured lean mass of upper limbs divided by (height)2 . Relative grip strength was calculated as grip strength divided by height. Decrease in bone mineral content (BMC), total volumetric bone mineral density (Tt.vBMD), cortical thickness (Ct.Th), cortical area (Ct.Ar) and cortical vBMD (Ct.vBMD) accelerated with age. Trabecular area (Tb.Ar) expansion and trabecular bone deterioration accelerated with age. Men in the first RALM-u.l. quartile had more rapid loss of BMC, Tt.vBMD, Ct.Th, Ct.vBMD and Ct.Ar vs. the highest quartile. They had more rapid increase in Tb.Ar. Men in the lowest quartile of grip strength had greater decrease in BMC, Tt.vBMD, Ct.Th, Ct.vBMD, Ct.Ar, and greater increase in Tb.Ar vs. the highest quartile. In the models including ALM-u.l. and grip strength (not corrected for height), both muscle-related variables were associated with more rapid bone microarchitectural deterioration (slightly more so for grip strength). Trabecular vBMD (Tb.vBMD) and Central.Tb.vBMD increased in men having higher muscle mass and strength. Trends in trabecular number and thickness did not differ across the groups in all the analyses. Thus, in men, aging-related deterioration of bone microarchitecture was most rapid after the age of 80. Low grip strength (and slightly more weakly low RALM-u.l.) is associated with the more rapid decrease in Tt.vBMD and cortical variables, and with greater Tb.Ar expansion. In conclusion, dynapenia and sarcopenia contribute to the deterioration of bone microarchitecture in older men. © 2018 American Society for Bone and Mineral Research.

Perinatal DNA Methylation at CDKN2A Is Associated With Offspring Bone Mass: Findings From the Southampton Women's Survey.

ABSTRACTPoor intrauterine and childhood growth has been linked with the risk of osteoporosis in later life, a relationship that may in part be mediated through altered epigenetic regulation of genes. We previously identified a region within the promoter of the long non‐coding RNA ANRIL encoded by the CDKN2A locus, at which differential DNA methylation at birth showed correlations with offspring adiposity. Given the common lineage of adipocytes and osteoblasts, we investigated the relationship between perinatal CDKN2A methylation and bone mass at ages 4 and 6 years. Using sodium bisulfite pyrosequencing, we measured the methylation status of the 9 CpGs within this region in umbilical cord samples from discovery (n = 332) and replication (n = 337) cohorts of children from the Southampton Women's Survey, whose bone mass was assessed by dual‐energy X‐ray absorptiomietry (DXA; Hologic Discovery). Inverse associations were found between perinatal CDKN2A methylation and whole‐body minus head bone area (BA), bone mineral content (BMC), and areal bone mineral density (BMD). This was confirmed in replication and combined data sets (all p < 0.01), with each 10% increase in methylation being associated with a decrease in BMC of 4 to 9 g at age 4 years (p ≤ 0.001). Relationships were similar with 6‐year bone mass. Functional investigation of the differentially methylated region in the SaOS‐2 osteosarcoma cell line showed that transcription factors bound to the identified CpGs in a methylation‐specific manner and that CpG mutagenesis modulated ANRIL expression. In conclusion, perinatal methylation at CDKN2A is associated with childhood bone development and has significance for cell function. © 2017 The Authors. Journal of Bone and Mineral Research Published by Wiley Periodicals Inc.

Response of Rat Tibia to Prolonged Unloading Under the Influence of Electrical Stimulation at the Dorsal Root Ganglion

Immobilization of weight bearing skeletons or microgravity results in disuse osteoporosis in both human and animals. Our previous study demonstrated that electrical stimulation at the dorsal root ganglion (DRG) with an implantable micro-electrical stimulation system (IMESS) could trigger secretion of bone anabolic calcitonin gene-related peptide (CGRP) and prevent bone loss in a short-term hindlimb unloading rat model. This study was designed to further investigate whether electrical stimulation to the DRG could prevent bone loss due to prolonged unloading. Eighteen adult rats were randomly assigned into three groups: cage control (CC), hindlimb unloading (HU), and hindlimb unloading with electrical stimulation (HUES). Electrical stimulation was applied via IMESS to the right DRGs at vertebral levels L4-L6 in HUES group for 6 weeks. Following unloading for 6 weeks, proximal tibia metaphysis was shown 64.0% decrease in bone mineral content (BMC) and 47.0% decrease in bone mineral density (BMD) in HU group while significant reduced bone lose with 2.7% increase in total BMC and only 9.2% decrease in total BMD in HUES group. Diaphyseal BMD decreased significantly in both HU and HUES group as compared with CC group. There was enhancement of CGRP expression in the DRGs in HUES group. This experimental study proved the proposed concept using electrical stimulation at the DRG for prevention of disuse-induced bone loss in a rat hindlimb suspension model.

Effects of whole-body vibration exercise on bone mineral content and density in thermally injured children

BackgroundLoss of bone mass, muscle mass, and strength leads to significant disability in severely burned children. We assessed the effects of exercise combined with whole-body vibration (WBV) on bone mass, lean mass (LM), and muscle strength in children recovering from burns. MethodsNineteen burned children (≥30% total body surface area [TBSA] burns) were randomly assigned to a 6-week exercise regimen either alone (EX; n=10) or in combination with a 6-week WBV training regimen (EX+WBV; n=9). WBV was performed concurrent to the exercise regimen for 5days/week on a vibrating platform. Dual-energy X-ray absorptiometry quantified bone mineral content (BMC), bone mineral density (BMD), and LM; knee extension strength was assessed using isokinetic dynamometry before and after training. Alpha was set at p<0.05. ResultsBoth groups were similar in age, height, weight, TBSA burned, and length of hospitalization. Whole-body LM increased in the EX group (p=0.041) and trended toward an increase in the EX+WBV group (p=0.055). On the other hand, there were decreases in leg BMC for both groups (EX, p=0.011; EX+WBV, p=0.047), and in leg BMD for only the EX group (EX, p<0.001; EX+WBV, p=0.26). Truncal BMC decreased in only the EX group (EX, p=0.009; EX+WBV, p=0.61), while BMD decreased in both groups (EX, p<0.001; EX+WBV group, p<0.001). Leg strength increased over time in the EX group (p<0.001) and the EX+WBV group (p<0.001; between-group p=0.31). ConclusionsExercise in combination with WBV may help attenuate regional bone loss in children recovering from burns. Studies are needed to determine the optimal magnitude, frequency, and duration of the vibration protocol, with attention to minimizing any potential interference with wound healing and graft closure.

WHOLE BODY AND REGIONAL BONE MINERAL CONTENT AND DENSITY IN WOMEN AGED 20-75 YEARS.

Dual-energy X-ray absorptiometry (DXA) allows measurement of whole body (WB) and regional bone mineral content (BMC) and density (BMD). To measure WB and regional bone area, BMC and BMD (arms, legs, ribs and pelvis) in women of different ages. 140 women participated (age range 20-75 yrs). Three subgroups were built: 20-44 yr (30 premenopausal women), 45-59 (80 women), and 60-75 (30 women). WB DXA was performed on a Hologic QDR 4500 A bone densitometer (Hologic Inc., Bedford MA). WB BMD T-scores were calculated by using the manufacturer-provided and the NHANES 1999-2004 reference databases, while the WB BMC Z-scores - based on the latter. Statistical analysis was performed on an IBM SPSS Statistics 19.0 for Windows platform (Chicago, IL). WB BMC and BMD Z-scores were consistently lower than the reference databases showing a difference of about 0.4 - 0.5 SD. The arms, legs and ribs lost more BMC after the age of 50-55, while the pelvis - much earlier. The total decreases in BMC were highest in the pelvis (26.36 %), followed by the arms (16.81 %) and whole body (15.91 %), while the bone area decreased mostly in the pelvis (13.23 %). The age-related declines in regional BMC, bone areas and BMD follow different patterns in appendicular and axial bones.

Osteoprotective effect of combination therapy of low-dose oestradiol with G15, a specific antagonist of GPR30/GPER in ovariectomy-induced osteoporotic rats.

Identified and cloned in 1996 for the first time, G protein-coupled oestrogen receptor (ER) 30 (GPR30/GPER) has been a hot spot in the field of sex hormone research till now. In the present study, we examined the effects of low-dose oestradiol (E2) combined with G15, a specific antagonist of GPR30 on ovariectomy (OVX)-induced osteoporosis in rats. Female Sprague-Dawley (SD) rats undergoing OVX were used to evaluate the osteoprotective effect of the drugs. Administration of E2 [35μg/kg, intraperitoneally (ip), three times/week) combining G15 (160μg/kg, ip, three times/week) for 6weeks was found to have prevented OVX-induced effects, including increase in bone turnover rate, decrease in bone mineral content (BMC) and bone mineral density (BMD), damage of bone structure and the aggravation in biomechanical properties of bone. The therapeutic effect of these two drugs in combination was better than that of E2 alone. Meanwhile, the administration of G15 prevented body weight increase or endometrium proliferation in the rats. In conclusion, administration of low-dose E2 combining G15 had a satisfactory bone protective effect for OVX rats, without significant influence on body weight or the uterus. This combination therapy may be an effective supplement of drugs in prevention and treatment for postmenopausal osteoporosis.

Osteoprotective effects of estrogen membrane receptor GPR30 in ovariectomized rats

G protein-coupled estrogen receptor 30 (GPR30) is expressed in bone tissue. However, little is known regarding the function of GPR30 in postmenopausal osteoporosis. In this study, we examined the effects of GPR30 on ovariectomy (OVX)-induced osteoporosis in rats, including the effects on proliferation, differentiation, and expression of proteins in osteoblasts. Administration of G1 (35μg/kg, ip, 3 times/week for 6 weeks), a specific agonist of GPR30, prevented OVX-induced increase in bone turnover rate, decrease in bone mineral content and bone mineral density, damage to bone structure, and aggravation of bone biomechanical properties. In addition, G1 did not affect uterine weight in the OVX rats. Osteoblasts isolated from calvarias from newborn rats were used to explore the underlying mechanisms. G1 (150pM) promoted proliferation and differentiation of osteoblasts through a positive feedback of GPR30, which then activated the PI3K-Akt, ERK, and CREB pathways. G15 (750pM), a specific antagonist of GPR30, reversed the above effects initiated by G1 treatment. In conclusion, activation of GPR30 protected bones against osteoporosis in OVX rats and exerted no untoward effect on the uterus. We suggest that GPR30 can be used as an effective therapeutic target for the prevention and treatment of postmenopausal osteoporosis.

Inhibitory Effects of Lanthanum Chloride on Wear Particle-Induced Osteolysis in a Mouse Calvarial Model.

Osteolysis is a bone disorder associated with progressive destruction of bone tissues. However, the effects of lanthanum chloride (LaCl3) on osteolysis remain unknown. Therefore, the aim of this study was to determine the effects of LaCl3 on osteolysis in vivo. In a mouse calvarial model, C57BL/6J mice were injected with wear particles with or without LaCl3. Microcomputed tomography, hematoxylin and eosin staining, and tartrate-resistant acid phosphatase staining were performed for the pathological characterization of calvariae, and eight calvariae per group were prepared for the assay of TNF-α, IL-1β, and RANKL secretion using quantitative enzyme-linked immunosorbent assay (ELISA). In mice treated with high-dose LaCl3, particle-induced osteolysis and inflammatory reaction were reduced compared with that in the vehicle-treated control. Moreover, treatment with high-dose LaCl3 suppressed the wear particle-induced decrease in bone mineral content, bone mineral density, and bone volume fraction. Bone destruction and resorption were higher in the LaCl3-treated group than in the saline-treated group but lower than those in the wear particle group. Finally, our results showed that treatment with a high dose of LaCl3 suppressed osteoclastogenesis. Thus, LaCl3 may represent a novel therapeutic agent for the treatment or prevention of wear particle-induced osteolysis and aseptic loosening.

Longitudinal bone mineral content and density in Rett syndrome and their contributing factors

Bone mass and density are low in females with Rett syndrome. This study used Dual energy x-ray absorptiometry to measure annual changes in z-scores for areal bone mineral density (aBMD) and bone mineral content (BMC) in the lumbar spine and total body in an Australian Rett syndrome cohort at baseline and then after three to four years. Bone mineral apparent density (BMAD) was calculated in the lumbar spine. Annual changes in lean tissue mass (LTM) and bone area (BA) were also assessed. The effects of age, genotype, mobility, menstrual status and epilepsy diagnosis on these parameters were also investigated.The baseline sample included 97 individuals who were representative of the total live Australian Rett syndrome population under 30years in 2005 (n=274). Of these 74 had a follow-up scan. Less than a quarter of females were able to walk on their own at follow-up. Bone area and LTM z-scores declined over the time between the baseline and follow-up scans. Mean height-standardised z-scores for the bone outcomes were obtained from multiple regression models. The lumbar spine showed a positive mean annual BMAD z-score change (0.08) and a marginal decrease in aBMD (−0.04). The mean z-score change per annum for those ‘who could walk unaided’ was more positive for LS BMAD (p=0.040). Total body BMD mean annual z-score change from baseline to follow-up was negative (−0.03). However this change was positive in those who had achieved menses prior to the study (0.03, p=0,040). Total body BMC showed the most negative change (−0.60), representing a decrease in bone mineral content over time. This normalised to a z-score change of 0.21 once adjusted for the reduced lean tissue mass mean z-score change (−0.21) and bone area mean z-score change (−0.14).Overall, the bone mineral content, bone mineral density, bone area and lean tissue mass z-scores for all outcome measures declined, with the TB BMC showing significant decreases.Weight, height and muscle mass appear to have impacts on bone formation and we recommend that nutritional intake should be closely monitored and a physical activity plan developed to optimise bone health. Pubertal progression should also be assessed in conjunction with serial densitometry assessments to track bone mass and density changes over time.

Decreases in bone mineral density at cortical and trabecular sites in the tibia and femur during the first year of spinal cord injury

BackgroundDisuse osteoporosis occurs in response to long-term immobilization. Spinal cord injury (SCI) leads to a form of disuse osteoporosis that only affects the paralyzed limbs. High rates of bone resorption after injury are evident from decreases in bone mineral content (BMC), which in the past have been attributed in the main to loss of trabecular bone in the epiphyses and cortical thinning in the shaft through endocortical resorption. MethodsPatients with motor-complete SCI recruited from the Queen Elizabeth National Spinal Injuries Unit (Glasgow, UK) were scanned within 5weeks of injury (baseline) using peripheral Quantitative Computed Tomography (pQCT). Unilateral scans of the tibia, femur and radius provided separate estimates of trabecular and cortical bone parameters in the epiphyses and diaphyses, respectively. Using repeat pQCT scans at 4, 8 and 12months post-injury, changes in BMC, bone mineral density (BMD) and cross-sectional area (CSA) of the bone were quantified. ResultsTwenty-six subjects (5 female, 21 male) with SCI (12 paraplegic, 14 tetraplegic), ranging from 16 to 76years old, were enrolled onto the study. Repeated-measures analyses showed a significant effect of time since injury on key bone parameters at the epiphyses of the tibia and femur (BMC, total BMD, trabecular BMD) and their diaphyses (BMC, cortical BMD, cortical CSA). There was no significant effect of gender or age on key outcome measures, but there was a tendency for the female subjects to experience greater decreases in cortical BMD. The decreases in cortical BMD in the tibia and femur were found to be statistically significant in both men and women. ConclusionsBy carrying out repeat pQCT scans at four-monthly intervals, this study provides a uniquely detailed description of the cortical bone changes that occur alongside trabecular bone changes in the first year of complete SCI. Significant decreases in BMD were recorded in both the cortical and trabecular bone compartments of the tibia and femur throughout the first year of injury. This study provides evidence for the need for targeted early intervention to preserve bone mass within this patient group.

Voluntary wheel running mitigates the stress-induced bone loss in ovariectomized rats.

In estrogen-deficient rodents with osteopenia, repetitive exposure to mild-to-moderate stress, which mimics the chronic aversive stimuli (CAS) of the modern urban lifestyle in postmenopausal women, has been hypothesized to cause the bone microstructure to further deteriorate. Recently, we have provided evidence in rats that voluntary impact exercise, e.g., wheel running, is as effective as pharmacological treatments for stress-induced anxiety and depression. The present study, therefore, aims to investigate whether a 4-week CAS exposure aggravates trabecular bone loss in ovariectomized (Ovx) rats, and whether CAS-induced bone loss can be rescued by voluntary wheel running. CAS was found to elevate the serum levels of corticosterone, a stress hormone from the adrenal gland. Dual energy X-ray absorptiometry revealed a decrease in bone mineral content (BMC) in the tibiae of CAS-exposed Ovx rats as compared to the CAS-free Ovx rats (control), while having no detectable effect on bone mineral density (BMD). Bone histomorphometric analysis of the proximal tibial metaphysis showed that CAS decreased trabecular bone volume and increased trabecular separation, which were completely restored to the baseline values of Ovx rats by voluntary wheel running. This CAS-induced trabecular bone loss in Ovx rats was probably due to an enhancement of osteoclast-mediated bone resorption, as indicated by increases in osteoclast surface and active erosion surface. Moreover, wheel running as well as non-impact exercise (endurance swimming) effectively increased the tibial BMD and BMC of CAS-exposed Ovx rats. It can be concluded that exercise is an effective intervention in mitigating CAS-induced bone loss in estrogen-deficient rats.

Bone Loss Over 1 Year of Training and Competition in Female Cyclists

To observe changes in hip, spine, and tibia bone characteristics in female cyclists over the course of 1 year of training. Prospective observational study. Laboratory. Female cyclists (n = 14) aged 26-41 years with at least 1 year of competition history and intent to compete in 10 or more races in the coming year. Women who train and compete in road cycling as their primary sport. Total body fat-free and fat mass and lumbar spine and proximal femur areal bone mineral density (aBMD) and bone mineral content (BMC) assessments by dual-energy x-ray absorptiometry. Volumetric BMD and BMC of the tibia were measured by peripheral quantitative computed tomography at sites corresponding to 4%, 38%, 66%, and 96% of tibia length. Time points were baseline and after 12 months of training and competition. Weight and body composition did not change significantly over 12 months. Total hip aBMD and BMC decreased by -1.4% ± 1.9% and -2.1% ± 2.3% (P < 0.02) and subtrochanter aBMD and BMC decreased by -2.1% ± 2.0% and -3.3% ± 3.7% (P < 0.01). There was a significant decrease in lumbar spine BMC (-1.1% ± 1.9%; P = 0.03). There were no significant bone changes in the tibia (P > 0.11). Bone loss in female cyclists was site specific and similar in magnitude to losses previously reported in male cyclists. Research is needed to understand the mechanisms for bone loss in cyclists.

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.

Inhibitory effect of a fermented soy product from lactic acid bacteria (PS-B1) on deterioration of bone mass and quality in ovariectomized mice

Objectives We investigated the effects of a fermented soy product from lactic acid bacteria (PS-B1) in preventing the decrease in bone mineral content and deterioration of trabecular bone structure in ovariectomized (OVX) mice.

The Use of Dual-Energy X-Ray Absorptiometry to Assess the Impact ofEimeriaInfections in Broiler Chicks

A number of parameters have been used to assess the impact ofcoccidiosis on chickens in clinical settings as well as in experimental studies. However, a rapid way to determine body composition would be useful to evaluate or compare responses to coccidia and could give further insight into the metabolic impact of infection. The current study evaluates the use of dual X-ray absorptiometry (DEXA) to determine the impact of coccidiosis on body composition in chicks receiving inoculations with single or mixed species of Eimeria. Chicks infected with Eimeria maxima, Eimeria acervulina, or Eimeria tenella had altered parameters of body composition as measured by DEXA at 6 days postinfection (PI). The greatest effects were noted in birds infected with E. acervulina or E. maxima, where lean mass and fat were reduced from control values about 75% and 85%, respectively. In chicks infected with E. tenella, tissue and fat were reduced about 10%. Bone mineral content (BMC) was about 75% of control values in birds infected with E. acervulina or E. maxima, but only E. acervulina altered bone mineral density (BMD). The decreases in BMC and BMD are likely due to malabsorption. In chicks receiving a mixed coccidian infection, all DEXA parameters were significantly decreased at 8 days PI compared with age-matched controls. As with single infections, BMD and BMC were significantly depressed (P < 0.05). Values of all DEXA parameters were near 92% of control values by day 16 PI. Analysis of all birds in the current study indicates DEXA tissue weight slightly underestimated the gravimetrically measured weight by about 3%. The current results demonstrate that DEXA is a potentially important tool for the rapid evaluation of the effect of coccidiosis on broiler chicks and suggest it can be useful for evaluation of vaccines and other disease controls.

Effects of postoperative weight-bearing on body composition and bone mineral density after uncemented total hip arthroplasty

To investigate whether a postoperative weight-bearing regimen affects changes in bone mineral density and body composition after uncemented total hip arthroplasty, and to investigate the changes over a 5-year period after the surgical procedure. Secondary analysis of a previous randomized controlled trial. A total of 39 patients were randomized to immediate full weight-bearing or partial weight-bearing for 3 months. Dual-energy X-ray absorptiometry was used to measure bone mineral density of the contralateral hip and both heels and to measure body composition. The weight-bearing regimen had no effect on change in bone mineral density or body composition after 3 and 12 months. At 5 years, there was a decrease in bone mineral density of 3% in the total body and 2-3% in the contralateral hip regions. At 5 years we found a decrease in total body bone mineral content of 5%, but no changes in fat mass or lean mass compared with preoperative values. The postoperative weight-bearing regimen had no effect on changes in body composition or bone mineral density. Five years after total hip arthroplasty there was a decrease in bone mineral content and bone mineral density, but no changes in lean mass or fat mass.

Sex-specific relationships between insulin resistance and bone mineral content in Korean adolescents

The aim of this study was to examine sex-specific relationships between insulin resistance (IR) and bone mineral content (BMC) according to age group and weight status. A population-based sample of 618 Korean adolescents (315 male and 303 female), aged 10-19years from the Fourth Korea National Health and Nutrition Examination Survey, 2009. They were divided into three age groups (10-12; 13-16; 17-19years) and two weight groups (non-overweight vs. overweight). IR was assessed using the homeostatic model of assessment of IR (HOMA-IR). Soft tissue composition (fat and lean mass) and BMC of the whole body, proximal femur, and lumbar spine were measured by dual energy X-ray absorptiometry. Adiposity (body mass index, waist circumference, or soft tissue composition), age, height, total cholesterol, triglycerides, high density lipoprotein cholesterol, alkaline phosphatase, serum vitamin D, dietary calcium and energy intake, and menarche for females were adjusted using general linear models of a complex sampling design. Higher HOMA-IR was associated with a decrease in BMC in male adolescents aged 13-19years after adjustment for adiposity and other confounders, while the associations were not significant in male adolescents aged 10-12years and female adolescents. After adjustment for adiposity and confounders, the inverse associations between HOMA-IR and BMC were more consistent in non-overweight male adolescents than in other weight groups (overweight males and non-overweight and overweight females). The unfavorable effect of IR on BMC appears to be more obvious in males aged 13-19years or non-overweight males than in females.