Changes In Bone Mineral Content Research Articles

Body Composition Changes in Severely Burned Children During ICU Hospitalization.

Prolonged hospitalization due to burn injury results in physical inactivity and muscle weakness. However, how these changes are distributed among body parts is unknown. The aim of this study was to evaluate the degree of body composition changes in different anatomical regions during ICU hospitalization. Retrospective chart review. Children's burn hospital. Twenty-four severely burned children admitted to our institution between 2000 and 2015. All patients underwent a dual-energy x-ray absorptiometry within 2 weeks after injury and 2 weeks before discharge to determine body composition changes. No subject underwent anabolic intervention. We analyzed changes of bone mineral content, bone mineral density, total fat mass, total mass, and total lean mass of the entire body and specifically analyzed the changes between the upper and lower limbs. In the 24 patients, age was 10 ± 5 years, total body surface area burned was 59% ± 17%, time between dual-energy x-ray absorptiometries was 34 ± 21 days, and length of stay was 39 ± 24 days. We found a significant (p < 0.001) average loss of 3% of lean mass in the whole body; this loss was significantly greater (p < 0.001) in the upper extremities (17%) than in the lower extremities (7%). We also observed a remodeling of the fat compartments, with a significant whole-body increase in fat mass (p < 0.001) that was greater in the truncal region (p < 0.0001) and in the lower limbs (p < 0.05). ICU hospitalization is associated with greater lean mass loss in the upper limbs of burned children. Mobilization programs should include early mobilization of upper limbs to restore upper extremity function.

Longitudinal effects of Parathyroid Hormone treatment on morphological, densitometric and mechanical properties of mouse tibia.

The use of Parathyroid Hormone (PTH) as bone anabolic is limited due to cost-benefit assessments. Preclinical studies evaluating the effects of PTH on bone have reported variable and often contradictory results. Here, we have applied a new approach using a combination of in-vivo longitudinal µCT, image processing techniques and finite element models to monitor early local changes in the whole tibia (divided in 40 compartments) and mechanical properties of female C57BL/6J mice treated with PTH 1-34, compared to controls. Compared with standard 3D bone morphometric analysis, our new approach allowed detection of much smaller and localised changes in bone mineral content (BMC) at very early time points (1 week vs 3 weeks with standard methods) and showed that changes do not occur uniformly over time and across the anatomical space. Indeed, in the PTH treated mice, significant changes in BMC were observed in the medial and posterior sectors of the proximal tibia, a week after treatment, and in the medial sector of the tibia midshaft region a week later (p < 0.05). By the third week, two thirds of the regions showed significantly higher values of BMC (p < 0.05). The effect of PTH on bone regional volume is similar to that on BMC, but there is almost no effect of PTH on bone tissue mineral density. The differences in estimated mechanical properties became significant after three weeks of treatment (p < 0.05). These results provide the first evidence of an early and localised PTH effect on murine bone, and show that our novel partitioning approach, compared to the standard evaluation protocol, allows a more precise quantification of bone changes following treatment, which would facilitate preclinical testing of novel mono- and/or combination therapies throughout the bone.

Longitudinal changes in bone mineral content and bone stiffness in adolescent male athletes: The PRO-BONE study

Longitudinal changes in bone mineral content and bone stiffness in adolescent male athletes: The PRO-BONE study

Effect of two prophylactic bolus vitamin D dosing regimens (1000 IU/day vs. 400 IU/day) on bone mineral content in new-onset and infrequently-relapsing nephrotic syndrome: a randomised clinical trial

Objectives: To examine the efficacy of two vitamin D dosages (1000 vs. 400 IU/day) for osteoprotection in children with new-onset and infrequently-relapsing nephrotic syndrome (IFRNS) receiving corticosteroids.Methods: This parallel-group, open label, randomised clinical trial enrolled 92 children with new-onset nephrotic syndrome (NS) (n = 28) or IFRNS (n = 64) to receive 1000 IU/day (Group A, n = 46) or 400 IU/day (Group B, n = 46) vitamin D (administered as a single bolus initial supplemental dose) by block randomisation in a 1:1 allocation ratio. In Group A, vitamin D (cholecalciferol in a Calcirol® sachet) was administered in a single stat dose of 84,000 IU on Day 1 of steroid therapy (for new-onset NS), calculated for a period of 12 weeks@1000 IU/day) and 42,000 IU on Day 1 of steroid therapy (for IFRNS, calculated for a period of 6 weeks@1000 IU/day). In Group B, vitamin D (cholecalciferol in a Calcirol® sachet) was administered as a single stat dose of 33,600 IU on Day 1 of steroid therapy (for new-onset NS, calculated for a period of 12 weeks@400 IU/day) and 16,800 IU on Day 1 of steroid therapy (for IFRNS, calculated for a period of 6 weeks@400 IU/day). The proportionate change in bone mineral content (BMC) was analysed in both groups after vitamin D supplementation.Results: Of the 92 children enrolled, 84 (n = 42 new onset, n = 42 IFRNS) completed the study and were included in the final analysis. Baseline characteristics including initial BMC, bone mineral density, cumulative prednisolone dosage and serum 25-hydroxycholecalciferol levels were comparable in the two groups. There was a greater median proportionate change in BMC in the children who received 1000 IU/day vitamin D (3.25%, IQR −1.2 to 12.4) than in those who received 400 IU/day vitamin D (1.2%, IQR −2.5 to 3.8, p = 0.048). The difference in proportionate change in BMC was only statistically significant in the combined new-onset and IFRNS, but not for IFRNS alone. There was a greater median proportionate change in serum 25-hydroxycholecalciferol, in the children who received 1000 IU/day vitamin D (20.6%, IQR 14.9–36.75) than in those who received 400 IU/day vitamin D (7.7%, IQR 3.5–18.5, p < 0.01). There was a greater median proportionate change in serum calcium in the children who received 1000 IU/day vitamin D (20%, IQR 13.1–29.0) than in those who received 400 IU/day vitamin D (11.3%, IQR 2.8–25.0, p = 0.03). Despite vitamin D therapy, BMC decreased from the baseline in 15 (32.6%) children receiving 1000 IU/day vitamin D and in 17 (36.9%) children receiving 400 IU/day vitamin D. There were no adverse effects attributable to vitamin D.Conclusion: The 1000 IU/day dose is marginally more effective than 400 IU/day and it is likely than an even larger dose is required. Further research is required to assess the efficacy and safety of vitamin D doses higher than 1000 IU/day.

Bone Mineral Monitoring with Dual-energy X-ray Absorptiometry (DEXA) in University Female Soccer Players

Soccer practice usually has high intensity movements involving sprints and change of direction; these implicate great strength over the bone structure having influence in the bone mineral since they facilitate bone stimulation, getting the appropriate parameters. Several studies show soccer practice or training, amateur as well as professional, lead to effective adaptations in the bone mass, as well as increases in bone mineral content (BMC) and bone mineral density (BMD). PURPOSE: The evaluation of changes in BMC and BMD during 4-month period, competition training of university, female, soccer players. METHODS: Body measurements were made at the beginning and at the end of 4-month training to 19 soccer players (20.87 ± 1.88 years old), through DEXA where BMC and BMD of arm, leg, trunk and total body were obtained. They were evaluated fasting at the morning, where every subject used a minimum of clothes for measurement. They also received informed consent explaining the test protocol, after that their height was measured. For the statistical analysis, the software SPSS version 21.0 was used. The Pearson product-moment correlation coefficient method was used. RESULTS: Meaningful increases were found from the initial take to the final take of BMC of arms and legs (p<0.01), and meaningful decrease on trunk and total body (p<0.01). Regarding BMD, significant increases were seen in legs and trunk (p<0.01), however in total body obtained a significant decrease (p<0.01) and not significant in arms (p=0.252), all of this during a 4-month study. CONCLUSIONS: Significant changes of lower limbs BMC and BMD are associated to the impact of kicking the ball, the sprints and the jumps that exist in soccer practice.

Bone mineral density & bone mineral content in Saudi children, risk factors and early detection of their affection using dual-emission X-ray absorptiometry (DEXA) scan

ObjectivesOptimization of bone health is a very important concern now a day. Achievement of optimal peak bone mineral mass is the best means of preventing osteoporosis in adulthood. Dual-energy X-ray absorptiometry (DXA) has become the basis for the evaluation of skeletal health in all ages. The aim of the workThis work aims to assess bone parameters in Alhasa children, Saudi Arabia. Patient & methodsA Cross-sectional survey study involves 126 healthy children (83) boys & (43) girls. Their ages range from (3–15years). ResultsThe mean of Bone mineral density (BMD) and bone mineral content (BMC) were (0.915±0.34 & 0.795±0.133) (43.93±29.4 & 37.63±11.2) in boys and in girls respectively. These values were lower than other areas in Saudi Arabia. BMD & BMC are statistically significant positive correlation with age in both sex, (r=0.567 P=0.000 & r=0.57 P<0.001) and (r=0.831, P=0.000 & r=0.818 P<0.001) respectively. Level of BMD & BMC acquisition were more in boys than girls in all age groups especially group (12–15years). The mean Z score shows significant steady decrease with age in both sexes. Height, Weight, BMI, showed significant positive correlations with changes in BMD & BMC. While Calcium level and Vitamin D level showed negative correlations. ConclusionThe average BMD & BMC in Saudi children is less than that of other races. It shows no significant difference with other Saudi population. Height, weight, BMI Calcium level and Vitamin D level can predict the changes in the BMC & BMD.

Six-year body composition change in male elite senior rugby league players

ABSTRACTThis study investigated the change in body composition and bone mineral content (BMC) of senior rugby league (RL) players between 2008 and 2014. Twelve male professional RL players (age, 24.6 ± 4.0 years; stature, 183.4 ± 8.4 cm) received a dual-energy X-ray absorptiometry scan during preseason in 2008 and 2014. Between 2008 and 2014, very likely increases in leg lean mass (LM), total trunk and leg BMC, and a likely increase in arm BMC and possible increases in body mass (BM), total and trunk fat mass (FM), and total, trunk and arm LM were observed. Unlikely decreases and unclear changes in leg and arm FM were also found. Large negative correlations were observed between age and BM (r = −0.72), LM (r = −0.70), FM (r = −0.61) and BMC (r = −0.84) change. Three participants (19.1 ± 1.6 years) increased LM by 7.0–9.3 kg. Younger players had the largest increases in LM during this period, although an older player (30-year old) still increased LM. Differences in body composition change were also observed for participants of the same age, thus contextual factors should be considered. This study demonstrates the individuality of body composition changes in senior professional rugby players, while considering the potential change in young athletes.

Femoral Neck External Size but not aBMD Predicts Structural and Mass Changes for Women Transitioning Through Menopause.

The impact of adult bone traits on changes in bone structure and mass during aging is not well understood. Having shown that intracortical remodeling correlates with external size of adult long bones led us to hypothesize that age-related changes in bone traits also depend on external bone size. We analyzed hip dual-energy X-ray absorptiometry images acquired longitudinally over 14 years for 198 midlife women transitioning through menopause. The 14-year change in bone mineral content (BMC, R2 = 0.03, p = 0.015) and bone area (R2 = 0.13, p = 0.001), but not areal bone mineral density (aBMD, R2 = 0.00, p = 0.931) correlated negatively with baseline femoral neck external size, adjusted for body size using the residuals from a linear regression between baseline bone area and height. The dependence of the 14-year changes in BMC and bone area on baseline bone area remained significant after adjusting for race/ethnicity, postmenopausal hormone use, the 14-year change in weight, and baseline aBMD, weight, height, and age. Women were sorted into tertiles using the baseline bone area-height residuals. The 14-year change in BMC (p = 0.009) and bone area (p = 0.001) but not aBMD (p = 0.788) differed across the tertiles. This suggested that women showed similar changes in aBMD for different structural and biological reasons: women with narrow femoral necks showed smaller changes in BMC but greater increases in bone area compared to women with wide femoral necks who showed greater losses in BMC but without large compensatory increases in bone area. This finding is opposite to expectations that periosteal expansion acts to mechanically offset bone loss. Thus, changes in femoral neck structure and mass during menopause vary widely among women and are predicted by baseline external bone size but not aBMD. How these different structural and mass changes affect individual strength-decline trajectories remains to be determined. © 2017 American Society for Bone and Mineral Research.

A retrospective analysis of longitudinal changes in bone mineral content in cystic fibrosis.

We aimed to describe the longitudinal changes in bone mineral content and influencing factors, in children with cystic fibrosis (CF). One hundred children (50 females) had dual X-ray absorptiometry (DXA) performed. Of these, 48 and 24 children had two to three scans, respectively over 10 years of follow-up. DXA data were expressed as lumbar spine bone mineral content standard deviation score (LSBMCSDS) adjusted for age, gender, ethnicity and bone area. Markers of disease, anthropometry and bone biochemistry were collected retrospectively. Baseline LSBMCSDS was >0.5 SDS in 13% children, between -0.5; 0.5 SDS, in 50% and ≤-0.5 in the remainder. Seventy-eight percent of the children who had baseline LSBMCSDS >-0.5, and 35% of the children with poor baseline (LSBMCSDS<-0.5), showed decreasing values in subsequent assessments. However, mean LS BMC SDS did not show a significant decline in subsequent assessments (-0.51; -0.64; -0.56; p=0.178). Lower forced expiratory volume in 1 s percent (FEV1%) low body mass index standard deviation scores (BMI SDS) and vitamin D were associated with reduction in BMC. Bone mineral content as assessed by DXA is sub-optimal and decreases with time in most children with CF and this study has highlighted parameters that can be addressed to improve bone health.

Three-Compartment Body Composition Changes in Professional Rugby Union Players Over One Competitive Season: A Team and Individualized Approach

The purpose of this study was to investigate the longitudinal body composition of professional rugby union players over one competitive season. Given the potential for variability in changes, and as the first to do so, we conducted individual analysis in addition to analysis of group means. Thirty-five professional rugby union players from one English Premiership team (forwards: n = 20, age: 25.5 ± 4.7 yr; backs: n = 15, age: 26.1 ± 4.5 yr) received one total-body dual-energy X-ray absorptiometry scan at preseason (August), midseason (January), and endseason (May), enabling quantification of body mass, total and regional fat mass, lean mass, percentage tissue fat mass (%TFM), and bone mineral content (BMC). Individual analysis was conducted by applying least significant change (LSC), derived from our previously published precision data and in accordance with International Society for Clinical Densitometry guidelines. Mean body mass remained stable throughout the season (p > 0.05), but total fat mass and %TFM increased from pre- to endseason, and from mid- to endseason (p < 0.05). There were also statistically significant increases in total-body BMC across the season (p < 0.05). In both groups, there was a loss of lean mass between mid- and endseason (p < 0.018). Individual evaluation using LSC and Bland–Altman analysis revealed a meaningful loss of lean mass in 17 players and a gain of fat mass in 21 players from pre- to endseason. Twelve players had no change and there were no differences by playing position. There were individual gains or no net changes in BMC across the season for 10 and 24 players, respectively. This study highlights the advantages of an individualized approach to dual-energy X-ray absorptiometry body composition monitoring and this can be achieved through application of derived LSC.

Quantifying The Contributions Of Sodium And Calcium In Bone Using Serial Dxa Scans

Bone has been hypothesized to serve as a sodium reservoir to buffer acute and chronic derangements in plasma sodium concentration ([Na+]). However, the contributions of sodium in bone have yet to be quantified in imaging studies. PURPOSE: To: 1) quantify the contributions of 6g sodium chloride (NaCl) on bone mineral content (BMC) and density (BMD) using dual energy x-ray absorptiometry (DXA) scans; 2) compare the contributions of 6g NaCl vs. 6g calcium citrate (Ca3Cit2) on both BMC and BMD; and 3) assess whole body BMC changes in humans 2hrs after oral ingestion of 6g NaCl. METHODS: 1) Ten DXA scans serially performed on a spine phantom (alone) and then with 6g NaCl placed over the spine as: solid 1g tablets; crushed tablets in 1.5mL Eppendorfs (tubes); and as a solution in tubes. 2) Ten DXA scans performed on a spine phantom plus 6g Ca3Cit2 as solid 1g tablets and as crushed tablets in tubes. 3) 14 healthy humans ingested 6g NaCl, (6x1g tablets) with DXA scans taken immediately after ingestion (+tablets; just swallowed) and then repeated 2hrs following oral tablet ingestion (-tablets; due to GI absorption). RESULTS: Mean spine phantom BMC (51.38±0.26g;CV=0.51%) was significantly lower compared with spine phantom plus: NaCl tablets (55.39±0.23;p<0.0001); NaCl tubes (54.87±0.26g;p<0.0001); NaCl solution (52.49±0.28g;p<0.0001); Ca3Cit2 tablets (55.05±0.31g;p<0.0001); and Ca3Cit2 tubes (53.68±0.39g;p<0.0001). Mean spine phantom BMD (0.989±0.004g/cm2;CV=0.50%) was statistically lower when compared with phantom plus: NaCl tablets (1.063g/cm2±0.005;p<0.0001); NaCl tubes (1.056±0.005g/cm2;p<0.0001); NaCl solution (1.006±0.005g/cm2;p<0.0001); Ca3Cit2 tablets (1.058±0.006g/cm2;p<0.0001); and Ca3Cit2 tubes (1.021±0.005g/cm2;p<0.0001). Absorption of 6gm NaCl tablets into the bloodstream 2hrs after oral ingestion reduced whole body BMC by -5.5±27g. CONCLUSIONS: 6g NaCl caused significant increases in BMC and BMD in DXA scans when placed over a spine phantom in: tablet form, when crushed in tubes; and dissolved in solution. Increases in BMC and BMD were similar between 6g NaCl and 6g Ca3Cit2. Alternatively, GI absorption of 6g NaCl tablets after oral ingestion resulted in a ~6g decrease in total body BMC. Thus, changes in BMC and BMD may reflect Na+ and Ca++ mobilization in DXA scan measurements.

Meet the Editorial Board Member

Optimization of bone health is a very important concern now a day. Achievement of optimal peak bone mineral mass is the best means of preventing osteoporosis in adulthood. Dual-energy X-ray absorptiometry (DXA) has become the basis for the evaluation of skeletal health in all ages.This work aims to assess bone parameters in Alhasa children, Saudi Arabia.A Cross-sectional survey study involves 126 healthy children (83) boys & (43) girls. Their ages range from (3–15 years).The mean of Bone mineral density (BMD) and bone mineral content (BMC) were (0.915 ± 0.34 & 0.795 ± 0.133) (43.93 ± 29.4 & 37.63 ± 11.2) in boys and in girls respectively. These values were lower than other areas in Saudi Arabia. BMD & BMC are statistically significant positive correlation with age in both sex, (r = 0.567 P = 0.000 & r = 0.57 P < 0.001) and (r = 0.831, P = 0.000 & r = 0.818 P < 0.001) respectively. Level of BMD & BMC acquisition were more in boys than girls in all age groups especially group (12–15 years). The mean Z score shows significant steady decrease with age in both sexes. Height, Weight, BMI, showed significant positive correlations with changes in BMD & BMC. While Calcium level and Vitamin D level showed negative correlations.The average BMD & BMC in Saudi children is less than that of other races. It shows no significant difference with other Saudi population. Height, weight, BMI Calcium level and Vitamin D level can predict the changes in the BMC & BMD.

Does Exercise Influence Pediatric Bone? A Systematic Review.

Periods of growth are thought to be the best time to increase bone mineral content, bone area, and areal bone mineral density (aBMD) through increased loading owing to high rates of bone modeling and remodeling. However, questions remain regarding whether a benefit of exercise is seen at all bone sites, is dependent on pubertal status or sex of the child, or whether other factors such as diet modify the response to exercise. We asked: (1) Does bone-loading exercise in childhood consistently increase bone mineral content, bone area, or aBMD? (2) Do effects of exercise differ depending on pubertal status or sex? (3) Does calcium intake modify the bone response to exercise? A literature search identified 22 unique trials for inclusion in this meta-analysis of the effect of exercise on bone changes by bone site, pubertal status, and sex. Sample sizes ranged from 16 to 410 subjects 3 to 18 years old with length of intervention ranging from 3 to 36 months. Fifteen of 22 trials were randomized (child randomized in nine, classroom/school randomized in six) and seven were observational trials. Ten trials were Level 2 and 11 were Level 3 based on the Oxford Centre for Evidence-Based Medicine criteria. Random effects models tested the difference (intervention mean effect-control mean effect) in percent change in bone mineral content, bone area, and aBMD. Meta-regression was used to identify sources of heterogeneity and funnel plots were used to assess publication bias. Children assigned to exercise had greater mean percent changes in bone mineral content and aBMD than children assigned to the control groups. Mean differences (95% CI) in bone mineral content percent change between intervention and control groups at total body (0.8; 95% CI, 0.3-1.3; p = 0.003), femoral neck (1.5; 95% CI, 0.5-2.5; p = 0.003), and spine (1.7; 95% CI, 0.4-3.1; p = 0.01) were significant with no differences in bone area (all p > 0.05). There were greater percent changes in aBMD in intervention than control groups at the femoral neck (0.6; 95% CI, 0.2-1.1; p = 0.006) and spine (1.2; 95% CI, 0.6-1.8; p < 0.001). Benefit of exercise was limited to children who were prepubertal (bone mineral content: total body [0.9; 95% CI, 0.2-1.7; p = 0.01], femoral neck [1.8; 95% CI, 0.0-3.5; p = 0.047], spine [3.7; 95% CI, 0.8-6.6; p = 0.01], and aBMD: femoral neck [0.6; 95% CI, -0.1-1.2; p = 0.07], spine [1.5; 95% CI, 0.7-2.3; p < 0.001]), with no differences among children who were pubertal (all p > 0.05). Changes in aBMD did not differ by sex (all p > 0.05), although the number of studies providing male-specific results was small (six of 22 eligible studies included boys). There was significant heterogeneity in bone mineral content and bone area for which a source could not be identified. Heterogeneity in spine aBMD was reduced by including calcium intake and intervention length as covariates. Three trials designed to determine whether calcium intake modified the bone response to exercise all reported a greater effect of exercise on leg bone mineral content in children randomized to receive supplemental calcium than those receiving placebo. Exercise interventions during childhood led to 0.6% to 1.7% greater annual increase in bone accrual, with effects predominantly among children who were prepubertal. If this effect were to persist into adulthood, it would have substantial implications for osteoporosis prevention. It is important to identify sources of heterogeneity among studies to determine factors that might influence the bone response to increased exercise during growth. Level II, therapeutic study.

GLP-1 Receptor Agonist Treatment Increases Bone Formation and Prevents Bone Loss in Weight-Reduced Obese Women.

Recent studies indicate that glucagon-like peptide (GLP)-1 regulates bone turnover, but the effects of GLP-1 receptor agonists (GLP-1 RAs) on bone in obese weight-reduced individuals are unknown. To investigate the role of GLP-1 RAs on bone formation and weight loss-induced bone mass reduction. Randomized control study. Outpatient research hospital clinic. Thirty-seven healthy obese women with body mass index of 34 ± 0.5 kg/m(2) and age 46 ± 2 years. After a low-calorie-diet-induced 12% weight loss, participants were randomized to treatment with or without administration of the GLP-1 RA liraglutide (1.2 mg/d) for 52 weeks. In case of weight gain, up to two meals per day could be replaced with a low-calorie-diet product to maintain the weight loss. Total, pelvic, and arm-leg bone mineral content (BMC) and bone markers [C-terminal telopeptide of type 1 collagen (CTX-1) and N-terminal propeptide of type 1 procollagen (P1NP)] were investigated before and after weight loss and after 52-week weight maintenance. Primary endpoints were changes in BMC and bone markers after 52-week weight maintenance with or without GLP-1 RA treatment. Total, pelvic, and arm-leg BMC decreased during weight maintenance in the control group (P < .0001), but not significantly in the liraglutide group. Thus, total and arm-leg BMC loss was four times greater in the control group compared to the liraglutide group (estimated difference, 27 g; 95% confidence interval, 5-48; P = .01), although the 12% weight loss was maintained in both groups. In the liraglutide group, the bone formation marker P1NP increased by 16% (7 ± 3 μg/L) vs a 2% (-1 ± 4 μg/L) decrease in the control group (P < .05). The bone resorption marker CTX-1 collagen did not change during the weight loss maintenance phase. Treatment with a long-acting GLP-1 RA increased bone formation by 16% and prevented bone loss after weight loss obtained through a low-calorie diet, supporting its role as a safe weight-lowering agent.

Genetic variants in adult bone mineral density and fracture risk genes are associated with the rate of bone mineral density acquisition in adolescence.

Previous studies have identified 63 single-nucleotide polymorphisms (SNPs) associated with bone mineral density (BMD) in adults. These SNPs are thought to reflect variants that influence bone maintenance and/or loss in adults. It is unclear whether they affect the rate of bone acquisition during adolescence. Bone measurements and genetic data were available on 6397 individuals from the Avon Longitudinal Study of Parents and Children at up to five follow-up clinics. Linear mixed effects models with smoothing splines were used for longitudinal modelling of BMD and its components bone mineral content (BMC) and bone area (BA), from 9 to 17 years. Genotype data from the 63 adult BMD associated SNPs were investigated individually and as a genetic risk score in the longitudinal model. Each additional BMD lowering allele of the genetic risk score was associated with lower BMD at age 13 [per allele effect size, 0.002 g/cm2 (SE = 0.0001, P = 1.24 × 10−38)] and decreased BMD acquisition from 9 to 17 years (P = 9.17 × 10−7). This association was driven by changes in BMC rather than BA. The genetic risk score explained ∼2% of the variation in BMD at 9 and 17 years, a third of that explained in adults (6%). Genetic variants that putatively affect bone maintenance and/or loss in adults appear to have a small influence on the rate of bone acquisition through adolescence.

Randomised controlled trial of the effectiveness of community group and home-based falls prevention exercise programmes on bone health in older people: the ProAct65+ bone study

exercise can reduce osteoporotic fracture risk by strengthening bone or reducing fall risk. Falls prevention exercise programmes can reduce fall incidence, and also include strengthening exercises suggested to load bone, but there is little information as to whether these programmes influence bone mineral density (BMD) and strength. to evaluate the skeletal effects of home (Otago Exercise Programme, OEP) and group (Falls Exercise Management, FaME) falls prevention exercise programmes relative to usual care in older people. men and women aged over 65 years were recruited through primary care. They were randomised by practice to OEP, FaME or usual care. BMD, bone mineral content (BMC) and structural properties were measured in Nottingham site participants before and after the 24-week intervention. participants were 319 men and women, aged mean(SD) 72(5) years. Ninety-two percentage of participants completed the trial. The OEP group completed 58(43) min/week of home exercise, while the FaME group completed 39(16) and 30(24) min/week of group and home exercise, respectively. Femoral neck BMD changes did not differ between treatment arms: mean (95% CI) effect sizes in OEP and FaME relative to usual care arm were -0.003(-0.011,0.005) and -0.002(-0.010,0.005) g cm(-2), respectively; P = 0.44 and 0.53. There were no significant changes in BMD or BMC at other skeletal sites, or in structural parameters. falls prevention exercise programmes did not influence BMD in older people. To increase bone strength, programmes may require exercise that exerts higher strains on bone or longer duration.

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.

G.P.98 : Changes in height and age adjusted DXA bone indices with oral bisphosphonate treatment in Duchenne muscular dystrophy

Osteoporosis is a major problem in Duchenne Muscular Dystrophy (DMD) due to long term glucocorticoid (GC) therapy and impaired mobility. There are currently no standard of care guidelines for detection or treatment of osteoporosis in DMD. There is limited data on bisphosphonate (BP) treatment of osteoporosis in pediatric DMD patients. This is the first study using height and age adjusted Z scores to assess changes in bone mineral density (BMD) and bone mineral content (BMC) in DMD boys treated with oral BP. To assess changes in bone mineral density (BMD) and bone mineral content (BMC) in DMD boys treated with oral BP. Retrospective study of total body (TB) and lumbar spine (LS) BMD and BMC by DXA in DMD boys treated with oral alendronate, studied between January 2005 and July 2012. Height- and age-adjusted Z-scores (HAZ) were derived. Paired t -tests were used to compare changes in BMD and BMC one year prior and one year post BP treatment. We studied 26 BP-treated DMD boys (mean age ± SD 10.9 ± 3.8 yrs and daily GC duration 3.3 ± 1.5 yrs at BP start). BP treatment duration at the end of the study period was 2.8 ± 1.1 yrs. Prior to starting BP, TB BMD and BMC-HAZ decreased progressively, while LS BMD and BMC-HAZ remained stable. Mean TB BMD and BMC-HAZ were −1.89 and −2.90 and mean LS BMD and BMC-HAZ were −0.89 and −1.07 at BP initiation. DXA bone indices stabilized or improved with BP treatment. There was significant improvement in LS BMD-HAZ ( p p p = 0.0092) after one year of BP treatment. Oral BP treatment stabilized further decline of TB bone indices, and improved LS BMD and BMC HAZ and TB BMC HAZ. Our study suggests that oral BP may be beneficial for bone health in DMD boys. Further study to assess clinical correlation of changes in DXA bone indices is needed to evaluate efficacy of oral BP treatment for osteoporosis in DMD patients.

Validation of urinary calcium isotope excretion from bone for screening anabolic therapies for osteoporosis.

Urinary excretion of calcium tracers in labeled individuals decreases in response to antiresorptive therapy, providing a tool to rapidly screen potential therapies. Using teriparatide, we demonstrate in this study that anabolic therapy also decreases tracer excretion, confirming that this method can also be used to screen potential anabolic therapies. Changes in urinary excretion of calcium tracers from a labeled skeleton may be a rapid and sensitive method to screen potential therapies for osteoporosis. This method has been used to screen antiresorptive therapies, but the effect of anabolic therapies on tracer excretion is unknown. Eight-month-old female Sprague Dawley rats (n = 11) were given 50 μCi (45)Ca iv. After a 1-month equilibration period, baseline urinary (45)Ca excretion and total bone mineral content (BMC) were measured. Rats were then treated with 30 μg/kg teriparatide sc per day, a bone anabolic agent, for 80 days. Urine was collected throughout the study and analyzed for (45)Ca and total Ca, and BMC was measured at the beginning and end of the study. Teriparatide decreased urinary (45)Ca excretion by 52.1 % and increased BMC by 21.7 %. The change in bone calcium retention as determined by the ratio of (45)Ca to total Ca excretion in urine from day 6 through 15 of teriparatide treatment was significantly correlated (p = 0.036) with the change in BMC after 80 days of teriparatide treatment. Urinary excretion of calcium tracers from labeled bone is an effective method to rapidly screen potential anabolic therapies for osteoporosis.

Effects of up to 15 years of recombinant human GH (rhGH) replacement on bone metabolism in adults with growth hormone deficiency (GHD): the Leiden Cohort Study.

Growth hormone deficiency (GHD) in adulthood may be associated with a decreased bone mineral density (BMD), a decreased bone mineral content (BMC) and an increased fracture risk. Recombinant human GH (rhGH) replacement induces a progressive increase in BMD for up to 5-7years of treatment. Data on longer follow-up are, however, scarce. Two hundred and thirty-adult GHD patients (mean age 47·1years, 52·6% female), of whom 88% patients had adult-onset (AO) GHD, receiving rhGH replacement for ≥5years were included in the study. Most patients had multiple pituitary hormone deficiencies. Bone turnover markers, BMC and BMD and T-scores at the lumbar spine and femoral neck were evaluated at baseline, and after 5, 10 and 15years of rhGH replacement. In addition, clinical fracture incidence was assessed. Mean lumbar spine BMD, lumbar spine BMC and T-scores gradually increased during the first 10years of rhGH replacement and remained stable thereafter. Largest effects of rhGH supplementation were found in men. In the small subset of patients using bisphosphonates, use of bisphosphonates did not impact additional beneficial effects in the long term. Low baseline BMD positively affected the change in BMD and BMC over time, but there was a negative effect of high GH dose at 1year on the change in BMD and BMC over time. Clinical fracture incidence during long-term rhGH replacement was 20.1/1000py. Fifteen years of rhGH replacement in GHD adults resulted in a sustained increase in BMD values at the lumbar spine, particularly in men, and stabilization of BMD values at the femoral neck. Clinical fracture incidence was suggested not to be increased during long-term rhGH replacement.