Total Body Less Head Bone Mineral Content Research Articles

Cross-sectional and longitudinal associations between the 24-hour movement behaviours, including muscle and bone strengthening activity, with bone and lean mass from childhood to adolescence

BackgroundThis study aimed to assess whether moderate-to-vigorous physical activity (MVPA), sport and exercise as a proxy measure of muscle and bone strengthening activity, sedentary behaviour, and sleep were associated with total-body-less-head (TBLH) bone mineral content (BMC) and TBLH lean mass cross-sectionally and longitudinally from age 6 to 9 years and age 9 to 11 years to age 15 to 17 years.MethodsWe used longitudinal data from a population sample of Finnish children from the Physical Activity and Nutrition in Children study (age 6 to 9 years: n = 478, 229 females; age 9 to 11 years: n = 384, 197 females; age 15 to 17 years: n = 222, 103 females). Linear regression analysed the cross-sectional and longitudinal associations between accelerometer-assessed MVPA, sedentary time and sleep, and questionnaire-assessed sport and exercise participation and screen time with dual-energy X-ray absorptiometry-assessed TBLH BMC and lean mass.ResultsIn females, MVPA at age 6 to 9 years was positively associated with TBLH BMC at age 15 to 17 years (β = 0.008, p = 0.010). Sport and exercise at age 9 to 11 years was positively associated with TBLH BMC (β = 0.020, p = 0.002) and lean mass (β = 0.343, p = 0.040) at age 15 to 17 years. MVPA at age 9 to 11 years was positively associated with TBLH lean mass (β = 0.272, p = 0.004) at age 15 to 17 years. In males, sleep at age 6 to 9 years was positively associated with TBLH lean mass (β = 0.382, p = 0.003) at age 15 to 17 years. Sport and exercise at age 9 to 11 years was positively associated with TBLH BMC (β = 0.027, p = 0.012) and lean mass (β = 0.721, p < 0.001) at age 15 to 17 years.ConclusionsPromoting engagement in the 24-hour movement behaviours in childhood, particularly sport and exercise to strengthen muscle and bone, is important in supporting bone and lean mass development in adolescence.Trial registrationNCT01803776; first trial registration date: 04/03/2013.

The Influence of Accelerometer Epoch Length on Associations of Physical Activity Intensity and Volume with Bone Outcomes.

Two accelerometer metrics (intensity-gradient and average-acceleration) can be used to determine the relative contributions of physical activity (PA) volume and intensity for health, but it is unknown whether epoch length influences the associations detected. This is important when considering bone health, as bone is particularly responsive to high intensity PA, which may be underestimated by longer epochs. This study aimed to assess the associations between average-acceleration, a proxy measure of PA volume, and intensity-gradient, reflective of PA intensity distribution, from PA data from 1-s to 60-s epochs at age 17 to 23 years with bone outcomes at age 23 years. This is a secondary analysis of 220 participants (124 females) from the Iowa Bone Development Study, a longitudinal study of bone health from childhood to early adulthood. Accelerometer-assessed PA data, captured at age 17 to 23 years, were summarised over 1-s, 5-s, 15-s, 30-s, and 60-s epochs, to generate average-acceleration and intensity-gradient from each epoch length, averaged across ages. Regression analysed associations between mutually adjusted average-acceleration and intensity-gradient with dual-energy X-ray absorptiometry assessed total-body-less-head (TBLH) bone mineral content (BMC), spine areal bone mineral density (aBMD), hip aBMD, and femoral neck cross-sectional area and section modulus at age 23 years. Intensity-gradient was positively associated with TBLH BMC in females, with spine aBMD in males, and with hip aBMD and geometry in both sexes, when a 1 to 5-s epoch was used. Average-acceleration was positively associated with TBLH BMC, spine aBMD and hip aBMD in males, generally when the adjustment for intensity-gradient was from > 1-s epochs. Intensity and volume were important for bone outcomes in both sexes and males, respectively. A 1 to 5-s epoch length was most appropriate to assess the mutually adjusted associations of intensity-gradient and average-acceleration with bone outcomes in young adults.

Relationships Between 25-Hydroxyvitamin D, Parathyroid Hormone, and Bone Mass in 4-Year-Old Children in Dhaka, Bangladesh

ObjectivesElevated serum parathyroid hormone (PTH) concentration was incidentally observed in a high proportion of children in a study in Dhaka, Bangladesh. We explored potential correlates of elevated PTH by estimating the association of PTH with 25-hydroxyvitamin D (25(OH)D) and associations of 25(OH)D and PTH with bone outcomes.MethodsData were obtained from the BONe and mUScle health in Kids study (BONUSKids; NCT03537443). Total-body less head (TBLH) bone mineral content (BMC) and areal bone mineral density (aBMD) were measured by dual-energy X-ray absorptiometry (DXA). Serum PTH and 25(OH)D were analyzed by chemiluminescent immunoassay and liquid chromatography-tandem mass spectrometry, respectively. BONUSKids participants (n = 642) with DXA, PTH and 25(OH)D data at 4 years were included. Associations between 25(OH)D, PTH and bone outcomes were estimated using unadjusted linear and two-phase linear spline regression models. Model fit was compared using AIC.ResultsAmong the 534 children who met inclusion criteria, 43% were vitamin D deficient (< 30nmol/L) and 30% had PTH > 6.9pmol/L. A non-linear inverse relationship was observed between 25(OH)D and PTH. Model fit was optimized with an inflection point at 25nmol/L, above which the association attenuated (< 25nmol/L: −0.16pmol/L per 1nmol/L change in 25(OH)D [95%CI −0.23, −0.10]; ≥ 25nmol/L: –0.02pmol/L [95% CI −0.04, −0.008]. 25(OH)D was positively linearly associated with TBLH BMC (0.39g per 1nmol/L change in 25(OH)D [95%CI 0.10: 0.69]) and aBMD (0.0004g/cm2 per 1nmol/L change in 25(OH)D [95% CI 0.0002, 0.0006]). There was no significant association between PTH and TBLH BMC. The non-linear association between PTH and TBLH aBMD was negative at PTH > 4pmol/L (< 4pmol/L: 0.002g/cm2 per 1pmol/L change in PTH [95% CI –0.006, 0.01], ≥ 4pmol/L: −0.002g/cm2 [95% CI −0.0038, −0.0002]).ConclusionsThe non-linear inverse association of PTH with 25(OH)D supports the hypothesis that vitamin D deficiency contributed to elevated PTH in this population. Although 25(OH)D was associated with bone outcomes, the magnitude of the association was similar at 25(OH)D concentrations below and above 25nmol/L. PTH was inconsistently associated with bone outcomes, suggesting single measurements of PTH may not be a useful marker of bone health in this setting.Funding SourcesCanadian Institutes of Health Research.

Bone accrual and structural changes over one year in youth with cystic fibrosis

BackgroundPediatric bone accrual governs peak bone mass and strength. Longitudinal studies of bone health in youth with cystic fibrosis (CF) may provide insight into CF-related bone disease (CFBD), a prevalent co-morbidity in adults with CF. MethodsThis one-year longitudinal study of youth with pancreatic insufficient CF, enrolled in a nutrition intervention study [n = 62 (36 M/26F)] 1) examined dual-energy x-ray absorptiometry (DXA)-defined lumbar spine (LS) and total body less head (TBLH) bone accrual and 2) compared their changes in peripheral quantitative computed tomography (pQCT) cortical and trabecular tibial bone density and geometry to those of a healthy reference group [n = 143 (68 M/75F)].Main outcome measures were 1) DXA: lumbar spine areal bone mineral density (LSaBMD) and total body less head bone mineral content (TBLH-BMC), sex- and pubertal status-specific, height velocity (HV)-adjusted or HV and lean body mass velocity (HV-LBMV)-adjusted annualized velocity-Z scores and 2) pQCT: age, sex, pubertal status and, when appropriate, tibial length adjusted Z-scores for bone architecture measures.DXA velocity-Z were compared to expected mean of 0 and correlations with clinical parameters (age, BMI-Z and FEV1%-predicted) tested. Within-subject comparisons of HV-adjusted and LBMV-HV-adjusted DXA velocity-Z were conducted in CF.pQCT Z-scores were compared between the two groups over one year using longitudinal models. Longitudinal relationships between measures of bone health and clinical parameters (age, BMI-Z and FEV1%-predicted) were examined in individuals with CF. ResultsDXA velocity-Z were higher than normal in females (p < 0.05) but not males with CF. HV-adjusted and LBMV-HV-adjusted velocity-Z did not differ for LSaBMD or TBLH-BMC.In males with CF, both HV-adjusted and LBMV-HV-adjusted LSaBMD velocity-Z scores correlated negatively with age (HV rho: −0.35; p = 0.045 and LBMV-HV rho: −0.47; p = 0.0046). In males with CF BMI-Z correlated positively with HV-adjusted LSaBMD velocity-Z (rho: 0.37; p = 0.034), but this relationship did not persist for LBMV-HV (rho: 0.14; p = 0.42). In females with CF, no correlations between LSaBMD velocity-Z scores and age or BMI-Z were found (all p > 0.05). No correlations between LSaBMD velocity-Z scores and FEV1%-predicted were seen in either sex (all p > 0.12). TBLH-BMC velocity Z-scores were not correlated with clinical parameters in either sex (all p > 0.1).At baseline, multiple pQCT parameters were lower in CF (p < 0.05). pQCT Z-scores did not differ between baseline and one-year in either CF or reference group. In a longitudinal model comparing pQCT-Z changes in CF and reference, multiple pQCT-Z outcomes remained lower in CF, but the changes in parameters did not differ in CF vs reference (all p > 0.26). Lower pQCT outcomes in CF were largely restricted to males (CF group*female sex interaction beta coefficients > 0). In this combined longitudinal model, of both CF and reference, BMI-Z was positively associated with pQCT-Z parameters(p < 0.001).Multiple pQCT-Z outcomes positively correlated with both BMI-Z and FEV1%-predicted in males with CF, and with FEV1%-predicted in females with CF (p < 0.05). Age was negatively associated with section modulus (p = 0.001) in males and with cortical density-Z in females (p < 0.001). ConclusionsWith improved longevity, bone health in CF is of increasing importance. On average, bone accrual was preserved in youth with CF, and while deficits in bone geometry and strength were found, these deficits did not worsen over the one-year study. Lower LS bone accrual with increasing age suggests emerging adulthood is a period of vulnerability in CF while the role of LBM in bone health is underscored by the lack of relationship between LBMV-adjusted accrual and BMI. These findings may be useful in targeting screening practices and interventions.

Effects of vitamin D and high dairy protein intake on bone mineralization and linear growth in 6- to 8-year-old children: the D-pro randomized trial

Vitamin D and dairy protein may stimulate bone mineralization and linear growth in children, but previous studies show inconsistent results and have not examined their combined effects. To investigate combined and separate effects of vitamin D supplementation and high-protein (HP) compared with normal-protein (NP) yogurt intake on children's bone mineralization and linear growth. In a 2×2-factorial trial, 200 healthy, 6- to 8-year-old, Danish, children with light skin (55°N) were randomized to 20µg/d vitamin D3 or placebo and to substitute 260g/d dairy with HP (10g protein/100g) or NP (3.5g protein/100g) yogurt for 24 weeks during an extended winter. Outcomes were total body less head (TBLH) and lumbar spine bone mineral density (BMD), bone mineral content (BMC), and bone area (BA) by dual-energy X-ray absorptiometry, height, and biomarkers of bone turnover and growth. The primary outcome was TBLH BMD. In total, 184 children (92%) completed the study. The baseline serum 25-hydroxyvitamin D was 80.8±17.2nmol/L, which increased by 7.2±14.1nmol/L and decreased by 32.3±17.5nmol/L with vitamin D and placebo, respectively. The baseline protein intake was 15.4±2.4 energy percentage (E%), which increased to 18.3±3.4 E% with HP. There were no vitamin D-yogurt interactions and no main effects of either intervention on TBLH BMD. However, vitamin D supplementation increased lumbar spine BMD and TBLH BMC compared to placebo, whereas HP groups showed lower increments in lumbar spine BMD, TBLH BMC and BA, and plasma osteocalcin compared to NP groups. Height, growth factors, and parathyroid hormone levels were unaffected. Although there were no effects on whole-body BMD, vitamin D increased bone mass and spinal BMD, whereas high compared with normal dairy protein intake had smaller incremental effects on these outcomes. This supports a recommended vitamin D intake of around 20µg/d during winter but not use of HP dairy products for improved bone mineralization among healthy, well-nourished children. This trial was registered at clinicaltrials.gov as NCT03956732.

Does the severity of obesity influence bone density, geometry and strength in adolescents?

Relationships between the severity of obesity and bone health remain underexplored. To compare whole-body and localized bone mineral content (BMC) and density (BMD), trabecular bone score (TBS) and hip geometry and strength between adolescents with obesity versus extreme obesity. This cross-sectional study included 154 adolescents (12-15 years, 62% females) who were classified as having obesity (OG, [95th-99th] percentile) or extreme obesity (EOG, >99th percentile). Fat mass (FM), lean mass (LM), BMC, BMD for total-body-less-head (TBLH), lumbar spine (LS), hip, TBS and geometric and strength indices at the narrow-neck (NN), femoral shaft (FS) and intertrochanteric regions (IT) were assessed by Dual-X-ray Absorptiometry (DXA). There was no significant sex-interaction. For both sexes, TBLH BMC and BMD were not different between groups. TBS was lower in EOG compared with OG in both sexes in univariate analysis and after adjustment with maturation and body weight (p < 0.05). Hip BMD was significantly higher in the EOG compared to OG only after adjustment with maturation and fat mass percentage (p < 0.05 for men, p < 0.01 for women). For both sexes, TBLH, LS and hip BMC and BMD positively correlated with weight, BMI, LM and FM. TBS negatively correlated with BMI-percentile in both sexes, with a negative correlation with FM for males alone. Hip BMC and BMD, BMD, ACT and CSA at the three hip sites positively correlated with BMI-percentile in males. Extreme obesity impacts bone health depending on anatomical sites, altering lumbar trabecular bone in both males and females adolescents.

Effect of HIV infection on growth and bone density in peripubertal children in the era of antiretroviral therapy: a cross-sectional study in Zimbabwe

SummaryBackgroundFaltered linear growth and pubertal delay, which are both common in children with HIV in sub-Saharan Africa, might affect adolescent bone accrual and future fragility fracture risk. We investigated the association of HIV with bone density adjusted for skeletal size in peripubertal children in Zimbabwe.MethodsWe did a cross-sectional study of baseline data from the IMVASK cohort, which enrolled children aged 8–16 years with HIV who had been taking antiretroviral therapy (ART) for at least 2 years, and children of the same age without HIV. Children with HIV were recruited from public sector HIV clinics at Parirenyatwa General Hospital and Harare Central Hospital (Harare, Zimbabwe), and children without HIV were recruited from six schools in the same suburbs that the hospitals serve. Sociodemographic, clinical, and anthropometric data were collected. Dual-energy X-ray absorptiometry (DXA) was used to measure the bone outcomes of total-body less-head bone mineral content for lean mass adjusted for height (TBLH-BMCLBM), and lumbar spine bone mineral apparent density (LS-BMAD), and we assessed the prevalence of low TBLH-BMCLBM and low LS-BMAD (defined by Z-scores of less than −2·0). Size adjustment techniques were used to overcome the size dependence of DXA measurement. We used linear regression models, with multiple imputation for missing data, to assess relationships between risk factors and TBLH-BMCLBM and LS-BMAD Z-scores in children with and without HIV.FindingsWe recruited 303 children with HIV (mean age 12·4 years [SD 2·5]; 151 [50%] girls) and 306 children without HIV (mean age 12·5 years [SD 2·5]; 155 [51%] girls). In children with HIV, median age of HIV diagnosis was 3·0 years (IQR 1·2–5·8), and median ART duration was 8·1 years (6·2–9·5); for 102 (34%) children, ART included tenofovir disoproxil fumarate (TDF). Children with HIV had a higher prevalence of low TBLH-BMCLBM Z-score than children without HIV (29 [10%] of 279 children with available data vs 18 [6%] of 292 with available data; p=0·066) and a higher prevalence of low LS-BMAD Z-score (40 [14%] of 279 vs 17 [6%] of 293 with available data; p=0·0007). HIV and male sex were associated with earlier pubertal (Tanner) stage. The negative associations between HIV and Z-scores for TBLH-BMCLBM and LS-BMAD were more pronounced with pubertal maturation, particularly in girls. Among children with HIV, TDF exposure and orphanhood were associated with lower TBLH-BMCLBM Z-score in confounder-adjusted analysis. Current TDF use (vs non-TDF-based ART) was associated with a reduction in TBLH-BMCLBM Z-score of 0·41 (95% CI 0·08–0·74; p=0·015) and in LS-BMAD Z-score of 0·31 (0·08–0·69; p=0·12).InterpretationDespite ART, HIV is associated with substantial skeletal deficits towards the end of puberty. The extent of bone deficits associated with TDF and its widespread use in children in sub-Saharan Africa are a concern for future adult fracture risk.FundingWellcome Trust.

Effect of Maternal Prenatal and Postpartum Vitamin D Supplementation on Offspring Bone Mass in Early Childhood: Follow-Up of a Randomized Controlled Trial

ObjectivesMaternal vitamin D status has gained substantial attention as a modifiable contributor to offspring musculoskeletal health, yet there is a paucity of trial-derived data to corroborate effects of prenatal or postpartum vitamin D supplementation on offspring bone mass accrual. Among maternal-infant pairs in Bangladesh, we aimed to examine the hypothesized causal association of early life vitamin D exposure with musculoskeletal health in childhood. MethodsIn a double-blind dose-ranging trial of maternal vitamin D3 supplementation (Maternal Vitamin D for Infant Growth Trial), healthy pregnant women (n = 1300) were recruited at 17–24 weeks’ gestation and randomly assigned to receive a prenatal; postpartum regimen of 0;0,4200;0,16,800;0,28,000;0 or 28,000;28,000 IU vitamin D3/week until 26 weeks postpartum. In a follow-up study of offspring at 4 years of age (n = 642), bone mineral content (BMC) and bone mineral density (BMD) were measured by dual-energy X-ray absorptiometry. Between-group differences were assessed by independent t-tests (28,000 IU/week prenatally vs placebo) and linear regression (each vitamin D treatment group vs placebo) with bootstrapping (1000 replications). ResultsWhole-body (WB), total-body-less-head (TBLH) and head-only BMC were similar in the combined high-dose prenatal and placebo groups (mean difference [95% CI] = 6.81g [–8.70, 22.32], 0.61g [–10.90, 12.13] and 1.71g [–3.54, 6.96], respectively). None of the mean values for WB or TBLH BMC or BMD in each vitamin D group were different from placebo (P > 0.05 for all comparisons). Although head BMD was slightly greater in offspring of women assigned to the 28,000;28,000 IU regimen compared to placebo (mean difference [95% CI] = 0.024g/cm2 [0.0009, 0.047], P = 0.042), the effect was attenuated and no longer significant upon adjustment for child height, weight, and sex (P = 0.11). ConclusionsIn a population with high prevalence of vitamin D deficiency, our findings do not support the use of maternal prenatal vitamin D supplementation, with or without postpartum supplementation, for improvement of child BMC or BMD at 4 years of age. Funding SourcesCanadian Institutes for Health Research and the Bill and Melinda Gates Foundation.

The Positive Relationship between Moderate-to-Vigorous Physical Activity and Bone Mineral Content Is Not Mediated by Free Leptin Index in Prepubertal Children: The PANIC Study.

Purpose: Moderate-to-vigorous physical activity (MVPA) positively influences bone mineral content (BMC) in prepubertal children, but it is unknown whether this relationship is partially mediated by free leptin index. The aim of this study was to examine whether the relationship between MVPA and total body less head (TBLH) BMC is mediated or moderated by free leptin index in prepubertal children. Methods: We performed a cross-sectional analysis on 401 children (194 girls) from baseline examinations of the Physical Activity and Nutrition in Childhood Study. We applied the four-way decomposition mediation analysis method to assess whether free leptin index, measured from fasted blood samples, mediated the relationship between accelerometer-measured MVPA and TBLH BMC measured by dual-energy X-ray absorptiometry. Results: MVPA had a positive controlled direct effect on TBLH BMC in girls and boys (β = 0.010 to 0.011, p < 0.05). There was no mediation or interaction between MVPA, free leptin index and TBLH BMC in girls or boys (β = −0.000 to 0.001, p > 0.05). Conclusion: Our study indicates that MVPA positively influences TBLH BMC through pathways not related to free leptin index in predominantly normal-weight prepubertal children, likely primarily through mechanical loading. The relationships between MVPA, free leptin index and TBLH BMC may be influenced by other factors such as pubertal status and adiposity, so it is unknown whether these observations extend to overweight and obese children at different stages of puberty.

Maternal pre-pregnancy underweight is associated with underweight and low bone mass in school-aged children

A number of studies have reported that pre-pregnancy overweight status is associated with offspring obesity, yet only a few studies have examined pre-pregnancy underweight status as it associates with offspring health. The aim of the present study was to assess the effect of pre-pregnancy underweight status in a mother on health outcomes in her offspring. To this end, the primary outcome examined in the present study was underweight status in the offspring, with a secondary outcome of offspring low bone mass. The present retrospective cohort study, conducted from 2008 to 2011, targeted a source population of all students registered as fifth-graders at three public elementary schools in Hamamatsu and Fukuroi cities. Maternal height and weight before and after pregnancy and offspring weight and height at birth were obtained from the Maternal and Child Health Handbook. Offspring weight and height at age 10years were measured using standard procedures. Offspring total body less head (TBLH) bone mineral content (BMC) was determined with a dual-energy X-ray absorptiometry scanner. Pre-pregnancy underweight status was found to be associated with an increased risk of an underweight status in female offspring (OR = 2.88, 95% CI 1.06-7.81). Offspring TBLH BMC in the underweight mother group was significantly lower than that in the non-underweight mother group. We determined that pre-pregnancy underweight status was more likely to lead to an underweight status and low TBLH BMC in school-aged offspring.

Effect of an interval rehabilitation program with home-based, vibration-assisted training on the development of muscle and bone in children with cerebral palsy -an observational study.

Objectives In children with cerebral palsy (CP), the most common cause of physical impairment in childhood, less muscle and bone growth has been reported, when compared with typically developing children. The aim of this study was to evaluate the effect of an intensive rehabilitation program including physiotherapy in combination with 6months of home-based, vibration-assisted training on muscle and bone growth in children with CP. Methods We included children with CP, who participated in a rehabilitation program utilizing whole-body vibration (WBV). Muscle mass was quantified by appendicular lean mass index (App-LMI) and bone mass by total-body-less-head bone mineral content (TBLH-BMC) assessed by Dual-energy X-ray absorptiometry (DXA) at the beginning of rehabilitation and one year later. To assess the functional muscle-bone unit, the relation of TBLH-BMC to TBLH lean body mass (TBLH-LBM) was used. Results The study population included 128 children (52 females, mean age 11.9±2.7). App-LMI assessed in kg/m2 increased significantly after rehabilitation. The age-adjusted Z-score for App-LMI showed no significant change. TBLH-BMC assessed in gram increased significantly. The Z-scores for TBLH-BMC decreased lesser than expected by the evaluation of the cross-sectional data at the beginning of rehabilitation. The parameter T B L H - B M C T B L H - L B M $\frac{TBLH-BMC}{TBLH-LBM}$ did not change relevantly after 12months. Conclusions Muscle growth and to a lesser extent bone growth could be increased in children with CP. The intensive rehabilitation program including WBV seemed to have no direct effect on the bone, but the observed anabolic effect on the bone, may only been mediated through the muscle.

Calcium Intake and Bone Mineral Acquisition during the Pubertal Growth Spurt: Three-Year Follow-Up of the Kitakata Kids Health Study in Japan

Calcium intake during a growth spurt may influence bone mineral acquisition. However, no population-based cohort studies have examined the relationship between calcium intake and whole-body bone mineral acquisition in Japanese children. The present study investigated the relationship between calcium intake and whole-body bone mineral acquisition in community-dwelling children in a northeast region of Japan using dual-energy X-ray absorptiometry. The source population for the baseline survey comprised all school children in 4th through 6th grades (275 children; age range, 10-12 y) in the Shiokawa area of Kitakata City, Fukushima. We obtained complete information from 220 children (100 girls and 120 boys), and analyzed total body less head (TBLH) bone mineral content (BMC), TBLH areal bone mineral density (aBMD), and bone mineral apparent density (BMAD) as an estimate of volumetric bone density. The Food Frequency Questionnaire for the Prevention and Management of Osteoporosis was validated in a previous study and used to estimate dietary nutrient intake. At baseline, mean calcium intake was 641 mg/d in girls and 660 mg/d in boys. Calcium intake in boys showed a significant (p<0.05) relationship with TBLH BMC and TBLH aBMD at follow-up, and with changes in TBLH BMC, TBLH aBMD, and TB BMAD from baseline to follow-up. After adjusting for potential confounding factors including body weight, we found no significant relationships between calcium intake and bone mineral parameters. Further studies are needed to clarify whether calcium intake affects bone mineral acquisition during pubertal growth spurts in the Japanese population.

The IMpact of Vertical HIV infection on child and Adolescent SKeletal development in Harare, Zimbabwe (IMVASK Study): a protocol for a prospective cohort study

IntroductionThe scale-up of antiretroviral therapy (ART) across sub-Saharan Africa (SSA) has reduced mortality so that increasing numbers of children with HIV (CWH) are surviving to adolescence. However, they experience a...

Associations between serum levels of insulin-like growth factor-I and bone mineral acquisition in pubertal children: a 3-year follow-up study in Hamamatsu, Japan

BackgroundEpidemiological data regarding the association between serum levels of IGF-I and bone mineral acquisition during childhood are scarce. Here, we investigated the association between serum levels of IGF-I and bone status during puberty.MethodsWe analyzed prospective 3-year follow-up data of 254 community-dwelling children who completed both baselines (at age 11.2 years) and follow-up (at age 14.2 years) surveys in Hamamatsu, Japan. Total body (TB) bone area and bone mineral parameters were assessed using dual-energy X-ray absorptiometry.ResultsDuring the 3-year follow-up period, there were significant (P < 0.05) increases in total body less head (TBLH) areal bone mineral density (aBMD), TBLH bone mineral content (BMC), and TB bone area, and a significant decrease in TB bone mineral apparent density (BMAD, volumetric bone mineral density, vBMD). IGF-I levels showed significant positive relationships with TBLH BMC and TBLH aBMD at both baseline and follow-up. TBLH aBMD in boys and TB BMAD in girls at follow-up showed significant increases from the lowest to highest quartiles of baseline IGF-I levels after adjusting for confounding factors. Similarly, changes in TBLH aBMD in boys and TB BMAD in girls during the 3-year follow-up period showed significant increases from the lowest to highest quartiles of baseline IGF-I levels after adjusting for confounding factors.ConclusionsThese results suggest that pubertal children with high levels of serum IGF-I tended to have high bone mineral acquisition later on.

Inflammatory markers and bone mass in children with overweight/obesity: the role of muscular fitness.

To examine which inflammatory markers are associated with bone mass and whether this association varies according to muscular fitness in children with overweight/obesity. Plasma interleukin-1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α), epidermal growth factor, vascular endothelial growth factor A (VEGF), and C-reactive protein were analyzed in 55 children aged 8-11 years. A muscular fitness score was computed. Bone mineral content (BMC) of the total body-less head (TBLH) and lumbar spine (LS) were assessed using dual-energy x-ray absorptiometry. IL-6 (β = -0.136) and VEGF (β = -0.099) were associated with TBLH BMC, while TNF-α (β = -0.345) and IL-1β (β = 0.212) were associated with LS BMC (P < 0.05). The interaction effect of muscular fitness showed a trend in the association of VEGF with TBLH BMC (P = 0.122) and TNF-α with LS BMC (P = 0.057). Stratified analyses by muscular fitness levels showed an inverse association of VEGF with TBLH BMC (β = -0.152) and TNF-α with LS BMC (β = -0.491) in the low-fitness group, while no association was found in the high-fitness group. IL-6, VEGF, TNF-α, and IL-1β are significantly associated with bone mass. Higher muscular fitness may attenuate the adverse effect of high VEGF and TNF-α on bone mass.

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

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

Physical Activity in Puberty is Associated with Total Body and Femoral Neck Bone Mineral Characteristics in Males at 18 Years of Age.

Background and objectives: Studies indicate that genetic and lifestyle factors influence optimal bone development. Adaptations in bone mineral characteristics related to physical activity (PA) are most often observed in pre- and peri-puberty. Longitudinal associations between bone mineral accrual and objectively measured PA in puberty are poorly understood. The present study aims to investigate whether pubertal PA at different intensities is related to bone mineral characteristics in individuals at 18 years of age. Materials and Methods: Anthropometrics, pubertal stage, bone age and PA by accelerometer were measured in 88 boys at the mean age of 12.1 (T1), 13.1 (T2), 14.0 (T3) and 18.0 years (T4). Different bone mineral parameters were measured by dual-energy X-ray at T4. Stepwise multiple regression analysis was performed to determine the effect of bone age, body mass and PA characteristics on measured bone mineral parameters at 18 years of age. Results: Total PA in puberty together with mean pubertal body mass predicted 35.5% of total body (TB) bone mineral density (BMD), 43.0% of TB less head (LH) bone mineral content (BMC) and 48.1% of BMC/height in individuals at 18 years of age. Vigorous PA and body mass in puberty predicted 43.2% of femoral neck (FN) BMD; bone age at T1, vigorous PA and body mass in puberty predicted 47.3% of FN BMC at 18 years of age. No associations between pubertal PA levels and lumbar spine bone mineral characteristics in individuals at 18 years of age were found. Conclusions: Physical activity in puberty has a significant impact on bone mineral characteristics in individuals at 18 years of age, with total PA being a significant predictor of TB BMD and TB LH BMC as well as BMC/height, whereas vigorous PA is a significant predictor of FN BMD and FN BMC.

Poor Glycemic Control Is Associated With Impaired Bone Accrual in the Year Following a Diagnosis of Type 1 Diabetes.

Type 1 diabetes (T1D) is associated with an increased fracture risk across the life course. The effects on bone accrual early in the disease are unknown. To characterize changes in bone density and structure over the year following diagnosis of T1D and to identify contributors to impaired bone accrual. Prospective cohort study. Academic children's hospital. Thirty-six children, ages 7 to 17 years, enrolled at diagnosis of T1D. Whole body and regional dual-energy X-ray absorptiometry and tibia peripheral quantitative computed tomography obtained at baseline and 12 months. The primary outcome was bone accrual assessed by bone mineral content (BMC) and areal bone mineral density (aBMD) velocity z score. Participants had low total body less head (TBLH) BMC (z = -0.46 ± 0.76), femoral neck aBMD (z = -0.57 ± 0.99), and tibia cortical volumetric BMD (z = -0.44 ± 1.11) at diagnosis, compared with reference data, P < 0.05. TBLH BMC velocity in the year following diagnosis was lower in participants with poor (hemoglobin A1c ≥7.5%) vs good (hemoglobin A1c <7.5%) glycemic control at 12 months, z = -0.36 ± 0.84 vs 0.58 ± 0.71, P = 0.003. TBLH BMC velocity was correlated with gains in tibia cortical area (R = 0.71, P = 0.003) and periosteal circumference (R = 0.67, P = 0.007) z scores in participants with good, but not poor control. Our results suggest that the adverse effects of T1D on BMD develop early in the disease. Bone accrual following diagnosis was impaired in participants with poor glycemic control and appeared to be mediated by diminished bone formation on the periosteal surface.

Bone mass development is sensitive to insulin resistance in adolescent boys.

Insulin resistance may exert a negative influence on bone mass in childhood and adolescence. The objective was to assess the association between insulin resistance and total body less head (TBLH) bone mineral content (BMC) and to investigate whether body composition, physical activity or osteocalcin levels may influence this association. A longitudinal study with follow-up over more than 6 years was performed and included 562 apparently healthy participants with a mean age of 9.6 years at baseline. Participants underwent DXA scanning at baseline. At the two follow-ups, participants had performed another DXA scanning, had blood samples taken for fasting insulin, glucose and osteocalcin and had physical activity measured with an accelerometer. HOMA-IR was calculated as an index of insulin resistance. HOMA-IR was negatively associated with TBLH BMC in boys at follow-ups (β = -31.4, p < 0.001) after adjustment for maturity, height, bone area, and baseline level of TBLH BMC. The negative association remained almost unchanged after further adjustments for body composition and physical activity. No association between HOMA-IR and TBLH BMC was found in girls. Insulin resistance may be detrimental for bone development through puberty in boys independent of body composition and the level of physical activity.

Changes in pediatric DXA measures of musculoskeletal outcomes and correlation with quantitative CT following treatment of acute lymphoblastic leukemia.

We previously reported significant gains in pQCT measures of tibia trabecular bone mineral density (BMD) and cortical structure following completion of therapy in children and adolescents with acute lymphoblastic leukemia (ALL). The objective of this study was to examine changes in DXA measures used in clinical practice and expressed as Z-scores using robust national reference data. Children and adolescents, ages 5 to 18 years were enrolled within 2 (median 0.8) years of completing ALL therapy. DXA total-body less-head bone mineral content (TBLH-BMC), and spine, total hip, femoral neck, and 1/3rd radius areal BMD (aBMD) were assessed in 45 participants at enrollment and 12-months later. Linear regression models examined correlates of changes in DXA Z-scores. Changes in DXA outcomes were compared to changes in tibia pQCT trabecular and cortical volumetric BMD (vBMD) and cortical area. At enrollment, DXA TBLH-BMC, spine and radius aBMD Z-scores were not significantly reduced in ALL survivors; however, total hip [median -0.74 (IQ range -1.51 to -0.04)] and femoral neck [-0.51 (-1.24 to 0.14)] aBMD Z-scores were lower (both p < 0.01) compared to reference data. DXA Z-scores at all skeletal sites increased over 12 months. Despite improvement, total hip Z-score remained lower at -0.55 (-1.05 to 0.18). The increases in TBLH-BMC, total hip and femoral neck aBMD Z-scores were more pronounced in those enrolled within 6 months of completing ALL therapy, compared to those enrolled at >6 months. Gains in TBLH-BMC, total hip, femoral neck and radius aBMD Z-scores were significantly associated with gains in tibia cortical area Z-scores (R = 0.56 to 0.67, p ≤ 0.001). Changes in TBLH and proximal femur sites were associated with gains in trabecular vBMD Z-scores (R = 0.37 to 0.40; p ≤ 0.01); these associations were not significant when adjusted for gains in cortical area. In summary, gains in DXA measures were most pronounced in total hip and femoral neck following ALL therapy. The gains in all DXA measures, with the exception of lumbar spine, reflected gains in cortical area. Overall, ALL survivors demonstrate skeletal recovery following completion of therapy; a small sub-group continue to demonstrate deficits and benefit from continued observation to ensure improvement over time.