Associations Between Body Composition and Bone Health in Children and Adolescents: A Systematic Review

Explainable predictive models of short stature and exploration of related environmental growth factors: a case-control study

BACKGROUND

Short stature is a prevalent pediatric endocrine disorder for which early detection and prediction are pivotal for improving treatment outcomes. However, existing diagnostic criteria often lack the necessary sensitivity and specificity because of the complex etiology of the disorder. Hence, this study aims to employ machine learning techniques to develop an interpretable predictive model for normal-variant short stature and to explore how growth environments influence its development.

METHODS

We conducted a case‒control study including 100 patients with normal-variant short stature who were age-matched with 200 normal controls from the Endocrinology Department of Nanjing Children's Hospital from April to September 2021. Parental surveys were conducted to gather information on the children involved. We assessed 33 readily accessible medical characteristics and utilized conditional logistic regression to explore how growth environments influence the onset of normal-variant short stature. Additionally, we evaluated the performance of the nine machine learning algorithms to determine the optimal model. The Shapley additive explanation (SHAP) method was subsequently employed to prioritize factor importance and refine the final model.

RESULTS

In the multivariate logistic regression analysis, children's weight (OR = 0.92, 95% CI: 0.86, 0.99), maternal height (OR = 0.79, 95% CI: 0.72, 0.87), paternal height (OR = 0.83, 95% CI: 0.75, 0.91), sufficient nighttime sleep duration (OR = 0.48, 95% CI: 0.26, 0.89), and outdoor activity time exceeding three hours (OR = 0.02, 95% CI: 0.00, 0.66) were identified as protective factors for normal-variant short stature. This study revealed that parental height, caregiver education, and children's weight significantly influenced the prediction of normal-variant short stature risk, and both the random forest model and gradient boosting machine model exhibited the best discriminatory ability among the 9 machine learning models.

CONCLUSIONS

This study revealed a close correlation between environmental growth factors and the occurrence of normal-variant short stature, particularly anthropometric characteristics. The random forest model and gradient boosting machine model performed exceptionally well, demonstrating their potential for clinical applications. These findings provide theoretical support for clinical identification and preventive measures for short stature.

Relationship of Skeletal Muscle Mass, Length of Sports Experience, and Sexual Maturity with Bone Density and Geometry in Adolescent Athletes

OBJECTIVE

To identify the relationship between length of sports experience, muscle mass, and sexual maturity with bone mineral density (BMD) and geometry in adolescent basketball and track and field athletes.

METHOD

The study included adolescent (11-18 years) athletes, of both sexes, who practiced basketball (n = 26) or track and field (n = 24). Skeletal muscle mass was measured by bioelectrical impedance analysis. Data on sports training and sexual maturity were collected through a questionnaire. Total body, lumbar, femoral, and forearm BMD were determined by dual-energy X-ray absorptiometry. Femoral scans were used to generate bone geometry measurements (femur strength index, cross-sectional area, cross-sectional moment of inertia, section modulus, and buckling ratio). Bone outcomes were compared between modalities by the Mann-Whitney U-test or Student's t-test and by analysis of covariance with adjustment for sports experience, sexual maturity, and skeletal muscle mass.

RESULTS

In the crude analysis, the basketball group had higher mean values for height, body weight, muscle mass, femoral neck BMD, cross-sectional area, and cross-sectional moment of inertia. In the covariate-adjusted analysis, the track and field group had higher total-body-less-head (0.995 vs. 1.035, p = 0.043), lumbar (1.012 vs. 1.107, p = 0.005), and radial (0.734 vs. 0.800, p = 0.005) BMD. Muscle mass was the main covariate influencing bone parameters, followed by sexual maturity.

CONCLUSION

Skeletal muscle mass was the main determinant of bone outcomes in adolescent athletes, followed by sexual maturity, underscoring the importance of considering these variables when assessing bone health in this population.

Assessing the Muscle-Bone Unit in Girls Exposed to Different Amounts of Impact-Loading Physical Activity-A Cross-Sectional Association Study

BACKGROUND/OBJECTIVES

In children, an association exists between muscle and bone, as well as between physical activity and osteogenesis. Impact loading is a factor in increasing bone accrual during growth. In this work, we explored the muscle-bone association in girls exposed to long-term physical activity at different levels of impact loading.

METHODS

Four groups of girls aged 7-16 were considered. The curricular (C; n = 22) group only had curricular physical activity at school (2 h/w). In addition to curricular physical activity, the girls in the dance (D; n = 21), gymnastics at lower training (GL; n = 14), and gymnastics at higher training (GH; n = 20) groups had 2 h/w, 4 h/w, and 4 h/w < training ≤ 12 h/w additional physical activity, respectively, for at least one year. A visual analysis estimated the respective amounts of impact-loading activity. The bone mineral content (BMC), areal bone mineral density (aBMD), and fat-free soft tissue mass (FFSTM) were assessed with dual-energy X-ray absorptiometry.

RESULTS

The results showed that, after adjusting for several confounders, statistically significant correlations were present between muscle mass and several bone mineral variables. A regression analysis confirmed the correlation in the data, and showed the marginal role of other body composition variables and physical activity for predicting BMC and BMD.

CONCLUSION

Skeletal muscle mass is a major determinant of the BMC and BMD of the TBLH, as well as of the Appendicular level, in girls exposed to different amounts of long-term impact-loading physical activity.

Occurrence of Body Posture Abnormalities in Overweight and Obese Children Aged 5-6 Years-Pilot Study

OBJECTIVES

The study aimed to assess the occurrence of body posture disorders and their changes under the influence of a physioprophylactic program in children depending on body weight.

METHODS

In the examined children, the general and segmental body composition and body posture were determined using a physiotherapeutic assessment based on the Kasperczyk method. Mass, overall, and segmental body composition were determined using the bioelectrical impedance method using a TANITA body composition analyzer. The study group of 76 children was divided due to body weight disorders into Group I (n = 51), in which BMI and fat mass values were within the normative limits for age and gender, and Group II (n = 19), comprising children whose body weight exceeded the norm and/or fat mass exceeded normative values. The examined children underwent a physioprophylactic. The program was conducted by qualified physiotherapists for 12 weeks, once a week for 30 min. The therapeutic program was focused on physioprevention of being overweight and the correction of body posture.

RESULTS

A distal distribution of fat mass was observed in the examined group. Asymmetry in the sagittal plane was found in 35% of children. No statistically significant differences were found in the presence of asymmetry in the sagittal plane between the groups. No statistically significant differences were found in the occurrence of posture irregularities between the groups.

CONCLUSIONS

There were no changes in the weight and body posture of the examined children under the influence of the physiotherapy program. The lack of correlation in the examined group between body weight and posture irregularities in 5-6-year-olds may suggest the acquisition of posture defects as a consequence of the persistence of overweight or obesity.

High muscular fitness level may positively affect bone strength and body composition in children with overweight and obesity

Muscular fitness plays a major role in bone health and body composition in overweight and obese children. It is key that the development of this muscle fitness is affected by absolute isometric strength and dynamic strength.

PURPOSE

To compare bone health and body composition between overweight/obese children considering muscular fitness (MF) levels, and to investigate whether weight-bearing dynamic or absolute isometric strength, both involved in the development of this muscular fitness, are more related with bone health.

METHODS

MF of 59 overweight or obese children (10.1 ± 0.9 years, 27 females) was measured by a countermovement jump (CMJ), handgrip, and maximal isometric strength of knee extension. Participants were divided into four groups depending on their MF level performing a cluster analysis: 16 children with high MF (HMF) in all tests, 18 with high performance in isometric strength (HIS), 15 with high performance in CMJ (HCMJ) and 10 low isometric and low dynamic force values (LMF). Body composition values were measured by dual energy X-ray absorptiometry, and bone strength values were assessed by peripheral quantitative computed tomography. Motor skills were evaluated using TGMD-3. Multivariate analysis of covariance test was applied to analyse bone strength differences between children in the different MF groups, using maturity offset, height and weight as covariates, and correlations were investigated.

RESULTS

HMF excelled in bone health. HIS had higher cortical bone area, periosteal circumference, bone mass, polar strength strain index and fracture load than LMF, while HCMJ only showed better results in trabecular bone area than LMF. HMF had significantly better values of fracture load and periosteal and endosteal circumferences than HCMJ, but not than HIS.

CONCLUSIONS

High MF level shows positive effects on bone health in overweight/obese children. Those with highest isometric strength had better bone health compared to those with higher dynamic strength.

TRIAL REGISTRATION

The research project was registered in a public database Clinicaltrials.gov in June 2020 with the identification number NCT04418713.

Insufficient Bone Mineralization to Sustain Mechanical Load of Weight in Obese Boys: A Cross-Sectional Study

CONTEXT

The increase in bone mineral content (BMC) and density (BMD) measured by dual-energy x-ray absorptiometry (DXA) in obese children may not sustain the mechanical load associated with weight, and the factors influencing bone mineralization are not well known.

OBJECTIVE

We described bone mineralization in boys with overweight/obesity and leanness in relation to body composition.

METHODS

Cross-sectional study in the Pediatric Endocrinology Unit of Angers University Hospital with 249 overweight/obese boys aged 8-18 who underwent DXA and insulin, testosterone, and IGF-1 measurements. Bone mineralization was compared with data from 301 lean boys of similar age and height from NHANES 2011-2015, using the same DXA model. Path analyses were performed to evaluate factors associated with total body less head (TBLH) BMC.

RESULTS

The mean age- and height-adjusted difference in TBLH BMC between obese and lean boys was 241 ± 20 g/cm2. Each 1 kg/m2 increase in BMI was associated with +39 ± 6 g of TBLH BMC in lean subjects vs + 25 ± 3 g in obese subjects (P < .05). Each 1 kg/m2 increase in lean BMI (LBMI) was associated with +78 ± 5 g of TBLH BMC in lean and obese boys, and each 1 kg/m2 increase in fat mass index (FMI) was associated with a decrease of 9 ± 3 g of TBLH BMC. The TBLH BMC was directly positively influenced by LBMI and indirectly and positively influenced by IGF-1, testosterone, and insulin (mediated through height and LBMI). FMI indirectly influenced TBLH BMC, both positively through LBMI and negatively through its negative impact on IGF-1 and testosterone.

CONCLUSION

The increase in bone mineralization in obese children does not adapt to the increase in body mass.

Predictive factors of bone strength variation in adolescent girls according to body composition

PURPOSE

This study examined correlations among anthropometric parameters, body composition, bone parameters and predictive factors of bone mass in adolescent girls with different body fat percentages (%fat).

METHODS

A total of 129 females aged 15-18 years were categorized into 3 groups using %fat-for-age at the 50th and 95th percentiles as cutoff points (normal, over, and excess %fat groups). We recorded anthropometric data and measured the speed of sound at the tibia and radius using quantitative ultrasound. Dual-energy x-ray absorptiometry (DXA) was used to measure body composition and bone parameters, including bone mineral density (BMD), bone mineral content (BMC), and the BMD-z-score (z-score) in the lumbar spine (LS) and whole body (WB). These parameters were compared among the 3 groups using bivariate and multivariate correlation analyses.

RESULTS

There were strong correlations among all anthropometric parameters, body composition, and DXA in the over %fat group. Lean parameters strongly correlated with LS and WB in the normal %fat group, whereas both lean mass (LM) and fat mass (FM) were positively correlated with BMC in the excess %fat group. The predictive factors of bone mass differed among the groups, as follows: lean body mass was predictive of BMD and BMC at both sites in the normal and over %fat groups; LM and body weight were predictive of LS-BMC and WB-bones, respectively, in the over %fat group; and FM was predictive of WB-bones in the excess %fat group. Body fat and waist circumference were negative predictors of bone mass.

CONCLUSION

Predictive factors of bone strength appear to depend on the amount of body fat in adolescent girls.

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

BACKGROUND

This 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.

METHODS

We 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.

RESULTS

In 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.

CONCLUSIONS

Promoting 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 REGISTRATION

NCT01803776; first trial registration date: 04/03/2013.

Determinants of bone parameters in young paediatric cancer survivors: the iBoneFIT project

BACKGROUND

Bone health is remarkably affected by endocrine side effects due to paediatric cancer treatments and the disease itself. We aimed to provide novel insights into the contribution of independent predictors of bone health in young paediatric cancer survivors.

METHODS

This cross-sectional multicentre study was carried out within the iBoneFIT framework in which 116 young paediatric cancer survivors (12.1 ± 3.3 years old; 43% female) were recruited. The independent predictors were sex, years from peak height velocity (PHV), time from treatment completion, radiotherapy exposure, region-specific lean and fat mass, musculoskeletal fitness, moderate-vigorous physical activity and past bone-specific physical activity.

RESULTS

Region-specific lean mass was the strongest significant predictor of most areal bone mineral density (aBMD), all hip geometry parameters and Trabecular Bone Score (β = 0.400-0.775, p ≤ 0.05). Years from PHV was positively associated with total body less head, legs and arms aBMD, and time from treatment completion was also positively associated with total hip and femoral neck aBMD parameters and narrow neck cross-sectional area (β = 0.327-0.398, p ≤ 0.05; β = 0.135-0.221, p ≤ 0.05), respectively.

CONCLUSION

Region-specific lean mass was consistently the most important positive determinant of all bone parameters, except for total hip aBMD, all Hip Structural Analysis parameters and Trabecular Bone Score.

IMPACT

The findings of this study indicate that region-specific lean mass is consistently the most important positive determinant of bone health in young paediatric cancer survivors. Randomised clinical trials focused on improving bone parameters of this population should target at region-specific lean mass due to the site-specific adaptations of the skeleton to external loading following paediatric cancer treatment. After paediatric cancer diagnosis, years from peak height velocity (somatic maturity) is critical for bone development.

Association between lean mass and adolescent idiopathic scoliosis: a meta-analysis

OBJECTIVE

The objective of this meta-analysis was to evaluate the association between lean mass and adolescent idiopathic scoliosis (AIS).

METHODS

English databases CENTRAL (The Cochrane Library and the Cochrane Back Review Group Trials Register), MEDLINE, EMBASE, PubMed, Web of Science and Chinese databases CBM, CNKI, VIP, WANGFANG DATA were searched for the relevant case control studies and cross-sectional studies. Two authors selected studies and extracted data independently. Data analysis was performed by Stata15.0.

RESULTS

Eight studies were included, with a total of 1771 cases of AIS and 6340 controls. AIS group had a lower lean mass compared to control group [MD =  - 1.95, 95% CI (- 2.96, - 0.93)]. In the subgroup analysis, female AIS patients had a lower lean mass than the control group [MD =  - 1.76, 95% CI (- 2.63, - 0.88)]. The mean difference of lean mass between AIS patients and control group in studies with adults [MD =  - 3.96, 95% CI (- 7.26, - 0.67)] is much greater than studies without adults [MD =  - 1.04, 95% CI (- 1.59, - 0.49)]. There was not statistically significant in European studies [MD =  - 2.10, 95% CI (- 4.35, 0.14)], but in Asian studies lean mass in AIS patients was lower than the control group [MD =  - 2.26, 95% CI (- 3.98, - 0.54)]. Study type, gender, age, and geography condition were thought to have no effect on the primary outcome of lean mass by subgroup analysis.

CONCLUSION

In the meta-analysis, AIS group had a lower lean mass compared to control group, which indicated that lean mass may be involved in the pathogenesis of AIS. But limited by the number of studies we included; the above conclusions need to be validated by more high-quality studies.

Body composition phenotypes and bone health in young adults: A cluster analysis

BACKGROUND AND AIMS

Lean mass is considered the best predictor of bone mass, as it is an excellent marker of bone mechanical stimulation, and changes in lean mass are highly correlated with bone outcomes in young adults. The aim of this study was to use cluster analysis to examine phenotype categories of body composition assessed by lean and fat mass in young adults and to assess how these body composition categories are associated with bone health outcomes.

METHODS

Cluster cross-sectional analyses of data from 719 young adults (526 women) aged 18-30 years from Cuenca and Toledo, Spain, were conducted. Lean mass index (lean mass (kg)/height (m)2), fat mass index (fat mass (kg)/height (m)2), bone mineral content (BMC) and areal bone mineral density (aBMD) were assessed by dual-energy X-ray absorptiometry.

RESULTS

A cluster analysis of lean mass and fat mass index z scores resulted in a classification of a five-category cluster solution that could be interpreted according to the body composition phenotypes of individuals as follows: high adiposity-high lean mass (n = 98), average adiposity-high lean mass (n = 113), high adiposity-average lean mass (n = 213), low adiposity-average lean mass (n = 142), and average adiposity-low lean mass (n = 153). ANCOVA models showed that individuals in clusters with a higher lean mass had significantly better bone health (z score: 0.764, se: 0.090) than their peers in other cluster categories (z score: -0.529, se: 0.074) after controlling for sex, age, and cardiorespiratory fitness (p < 0.05). Additionally, subjects belonging to the categories with a similar average lean mass index but with high or low-adiposity levels (z score: 0.289, se: 0.111; z score: 0.086, se: 0.076) showed better bone outcomes when the fat mass index was higher (p < 0.05).

CONCLUSIONS

This study confirms the validity of a body composition model using a cluster analysis to classify young adults according to their lean mass and fat mass indices. In addition, this model reinforces the main role of lean mass on bone health in this population and that in phenotypes with high-average lean mass, factors associated with fat mass may also have a positive effect on bone status.

Association of blood mercury levels with bone mineral density in adolescents aged 12-19

Bone mass increases rapidly in adolescence, and achieving higher bone mineral density (BMD) during this period can help prevent osteoporosis. However, the effects of metallic mercury on bone health remain controversial. Previous studies have discussed perimenopausal women and older adults, while the association of blood mercury with BMD in adolescents is yet to be studied. Date was collected from the National Health and Nutrition Examination Survey (NHANES) 2011-2018. Weighted multiple linear regression models were used to explore the association of blood mercury levels with BMD in adolescents, while smooth curve fittings and weighted generalized additive models were used to identify the potential nonlinear association. We found that blood mercury levels were negatively associated with BMD in adolescents, though not significantly, based on the results of statistical analyses of 2818 participants. Additionally, the trend in BMD with changes in blood mercury was different in male and female adolescents. We also found an inverted U-shaped association between blood mercury and BMD in male and Mexican-American adolescents. This suggests that increased blood mercury levels within a range may benefit bone health in male adolescents (inflection point: 5.44 nmol/L) and Mexican-American adolescents (inflection point: 5.49 nmol/L), while higher blood mercury levels may harm bone health. More prospective research is needed to confirm our findings.

Association of total body fat and fat distribution with bone mineral density among children and adolescents aged 6-17 years from Guangzhou, China

This study aimed to assess the associations of total body fat and fat distribution with bone mineral density (BMD) among children and adolescents in this cross-sectional study. A total of 1032 boys and 897 girls aged 6-17 years were enrolled between May 2019 and June 2019 in Guangzhou, China. BMD, total body fat (fat mass index [FMI] and body fat percentage [BF%]), and fat distribution (trunk-to-limb and android-to-gynoid ratios) were measured by dual-energy X-ray absorptiometry. Inverse probability of treatment weighting regression was used to explore the association between fat and BMD. Traditional regression of covariate adjustment was applied as sensitivity analysis. Regression with inverse probability weighting suggested BF% and android-to-gynoid ratio were negatively associated with BMD in boys (β =  - 0.12 and - 0.16, respectively; P < 0.05). Android-to-gynoid ratio was also inversely associated with BMD in girls (β =  - 0.08, P < 0.05). When stratified by age, the negative associations were retained in boys aged 12-17 years (β =  - 0.23 and - 0.25, respectively; P < 0.001). But for girls, it showed a positive association of FMI with BMD in the 6-9 years group (β = 0.33, P < 0.001) and a negative association between the android-to-gynoid ratio and BMD in the 10-17 years group (β =  - 0.10, P < 0.05). Traditional regression supported the robustness of the results.  Conclusion: Total body fat is positively associated with BMD in younger girls but inversely associated in older boys. As for abdominal adipose, it is associated with lower BMD in both older boys and girls. What is Known: • The lean mass has been consistently positively associated with bone mineral density (BMD) among children and adolescents. However, the impact of fat mass on BMD remained controversial. • Beyond total body fat, site-specific fat mass, especially abdominal adiposity, might impede bone formation. What is New: • The associations of total body fat and fat distribution with BMD in children and adolescents were gender- and age-specific. • More attention should be paid to the abdominal fat accumulation to promote bone health in older children.

Twelve weeks of a diet and exercise intervention alters the acute bone response to exercise in adolescent females with overweight/obesity

Introduction: Exercise and consumption of dairy foods have been shown to improve bone mineralization. However, little is known about the magnitude and timing of their synergistic effects on markers and regulators of bone metabolism in response to acute exercise in adolescent females with obesity, a population susceptible to altered bone metabolism and mineral properties. This study examined the influence of twelve weeks of exercise training and nutritional counselling on the bone biochemical marker response to acute exercise and whether higher dairy consumption could further influence the response. Methods: Thirty adolescent females (14.3 ± 2.0 years) with overweight/obesity (OW/OB) completed a 12-week lifestyle modification intervention involving exercise training and nutritional counselling. Participants were randomized into two groups: higher dairy intake (RDa; 4 servings/day; n = 14) or low dairy intake (LDa; 0-2 servings/d; n = 16). Participants performed one bout of plyometric exercise (5 circuits; 120 jumps) both pre- and post-intervention. Blood samples were taken at rest, 5 min and 1 h post-exercise. Serum sclerostin, osteocalcin (OC), osteoprotegerin (OPG), receptor activator nuclear factor kappa B ligand (RANKL), and C-terminal telopeptide of type 1 collagen (βCTX) concentrations were measured. Results: While there was an overall increase in sclerostin pre-intervention from pre to 5 min post-exercise (+11% p = 0.04), this response was significantly decreased post-intervention (-25%, p = 0.03) independent of dairy intake. The OPG:RANKL ratio was unresponsive to acute exercise pre-intervention but increased 1 h post-exercise (+2.6 AU; p < 0.001) post-intervention. Dairy intake did not further influence these absolute responses. However, after the 12-week intervention, the RDa group showed a decrease in the relative RANKL post-exercise response (-21.9%; p < 0.01), leading to a consistent increase in the relative OPG:RANKL ratio response, which was not the case in the LDa group. There was no influence of the intervention or dairy product intake on OC, OPG, or βCTX responses to acute exercise (p > 0.05). Conclusion: A lifestyle modification intervention involving exercise training blunts the increase in sclerostin and can augment the increase in OPG:RANKL ratio to acute exercise in adolescent females with OW/OB, while dairy product consumption did not further influence these responses.

Pubertal increment in insulin resistance is negatively related to lumbar bone mineral density in 18-year-old males

Transient insulin resistance seen during puberty is expected to favour body growth, but our results show that increment in insulin resistance even in physiological ranges during puberty might compromise lumbar spine bone mineral density accrual independently of body composition parameters, and therefore adult bone quality might be challenged.

INTRODUCTION

Insulin resistance (IR) might have a compromising effect on growing bone, and therefore adult bone quality might be challenged. The aim of the present study was to identify whether increases in IR during puberty contribute to bone mineral characteristics in males independently of body composition parameters.

METHODS

This is a retrospective cohort-based longitudinal observational study. Data from 85 subjects were included. Boys were studied annually during their pubertal years (12 years at baseline) and at follow-up at the age of 18 years. Anthropometry, bone age, fasting blood samples, body composition, total body, and lumbar spine bone mineral characteristics were measured. Insulin resistance was determined by homeostatic model assessment of IR (HOMA-IR). Multiple regression analysis was performed to determine the effect of changes in HOMA-IR during pubertal years as a longitudinal predictor to fixed bone mineral outcome variables at the age of 18 years. All models were adjusted to potential clinically justified confounding variables.

RESULTS

After adjustment to baseline bone indices and body composition-related predictors, the pubertal increment in the HOMA-IR was a negative independent predictor of lumbar spine bone mineral areal density (β =  - 0.202, p = 0.005) and lumbar spine bone mineral apparent density (β =  - 0.235, p = 0.005) in 18-year-old males.

CONCLUSIONS

Pubertal increment in IR has a potential diminishing effect on lumbar spine bone mineral density accrual independently of body composition parameters. Further studies are needed to clarify whether monitoring HOMA-IR during puberty may identify subjects at increased risk of low peak bone mass and possible osteoporosis in the future.

Relationship between body composition and bone mass in normal-weight and overweight adolescents

Adolescence is a period characterized by large accumulation of bone mass. Body composition is an important determinant of bone mass. This study aimed to assess the relationship of bone mass with lean mass (LM) and fat mass (FM) in normal-weight and overweight adolescents with consideration of sex, sexual maturation and physical activity covariates. A total of 118 adolescents (60 girls and 58 boys) aged between 10 and 14 years participated in the study. Individuals were classified as normal weight or overweight according to body mass index. Bone mineral density (BMD), bone mineral content (BMC), LM, and FM were measured by dual-energy X-ray absorptiometry. In normal-weight adolescents, LM (β = 0.725, p < 0.001) and FM (β = 0.185, p = 0.019) were associated with lumbar spine BMC, whereas in overweight adolescents only LM (β = 0.736, p < 0.001) was associated with lumbar spine BMC. Furthermore, in the normal-weight group, FM and LM were associated with total body less head BMD (LM, β = 0.792, p < 0.001; FM, β = 0.257, p = 0.007) and lumbar spine BMD (LM, β = 0.553, p < 0.001; FM, β = 0.199, p < 0.035). In the overweight group, only LM was associated with total body less head BMD (β = 0.682, p < 0.001) and lumbar spine BMD (β = 0.528, p < 0.001). LM was the main predictor of bone mass in normal-weight and overweight adolescents. FM was associated with bone mass in normal-weight adolescents only. LM may be considered an important and useful marker in adolescents, when investigating bone health in this population. Activities that promote LM gain to reduce the risk of bone fractures and diseases in adulthood are recommended.

Impact of an exercise program in children with inflammatory bowel disease in remission

BACKGROUND

The aim of our study was to investigate the impact of a structured exercise program on bone mineral density (BMD) and body composition parameters in children and adolescents with IBD in remission.

METHODS

Patients were recruited to participate in a 6-month exercise program. Total body less head (TLBH) dual energy X-ray absorptiometry (DXA) was used to measure BMD. The same method was used to assess fat mass (FM) and lean body mass (LBM) at baseline and at the completion of the program.

RESULTS

Based on the baseline and endpoint TBLH DXA measurements, a total of 42 study participants (25 boys; aged 15.3 ± 2.08 years) experienced an increase in BMD (from 0.959 ± 0.023 g/cm² to 0.988 ± 0.025 g/cm², p < 0.001) and LBM (from 37.12 ± 1.43 kg to 38.75 ± 1.61 kg, p = 0.012). Age- and sex-based BMD Z-score increased significantly (from -0.35 ± 0.15 to -0.28 ± 0.17, p = 0.020), whilst LBM Z-score did not significantly change (from -1.78 ± 0.23 to -1.71 ± 1.49, p = 0.908).

CONCLUSIONS

There was a significant improvement in BMD, age- and sex-based BMD Z-score, and LBM amongst study participants. Subgroup analysis showed that patients with CD and male study participants experienced significant improvement in all parameters, whilst patients with UC and IBD-U and female patients experienced improvement solely in BMD.

IMPACT STATEMENT

Children and adolescents with IBD, regardless of disease activity, are under increased risk of secondary osteoporosis and lean body mass deficits. A 6-month home-based structured exercise program leads to a significant improvement in bone mineral density and lean body mass. Exercise therapy should be explored as a potentially adjacent to standard treatment modalities.

The Influence of Body Composition on Bone Health in Long-term Survivors of Acute Lymphoblastic Leukemia in Childhood and Adolescence: Analyses by Dual-energy Radiograph Absorptiometry and Peripheral Quantitative Computed Tomography

BACKGROUND

The normal interrelationship of body composition with bone health is less clear in the context of disease. Survivors of acute lymphoblastic leukemia (ALL) exhibit sarcopenic obesity and osteopenia. The impact of body composition on bone health in such survivors was examined.

SUBJECTS AND METHODS

Survivors of ALL (N=74), >10 years from diagnosis, underwent dual-energy radiograph absorptiometry and peripheral quantitative computed tomography.

RESULTS

Whole-body bone mineral content (WB BMC) Z scores were greater in males than females, but WB BMC indices (WB BMC/height 2 ) were comparable (0.74±0.125 and 0.72±0.069, respectively). WB BMC index (I) and fat-free mass index correlated significantly with trabecular bone mineral density, only in males. Fat mass index and appendicular lean mass index showed no such correlations. WB BMCI and fat-free mass index also correlated, again predominantly in males, with measures of strength in both trabecular and cortical bone. WB BMCI also correlated strongly with trabecular number, thickness, and hole size, also only in males.

CONCLUSIONS

The results point to the need for enhancing muscle mass, measured by appendicular lean mass index, while reducing fat mass and maintaining good bone mineralization in long-term survivors of ALL to ensure the integrity of healthy bones.

Leptin levels were negatively associated with lumbar spine bone mineral content in children with overweight or obesity

AIM

Adipokines seem to play a role in bone morphogenesis, although this also depends on the mechanical forces applied to the skeleton. The aim was to assess the relationships of resting leptin and adiponectin with bone parameters and whether high muscular fitness levels affect these relationships in children with overweight or obesity.

METHODS

This cross-sectional study took part from 2014 to 2016 in Granada, Spain. Participants were recruited from University Hospitals, and we also used advertisements in local media and school contacts in the city. Adipokines were analysed in plasma. Muscular fitness was assessed by 1 repetition maximum in bench and leg press tests. Dual-energy X-ray absorptiometry was used to measure bone parameters.

RESULTS

We included 84 children (10.0±1.2y; 63% boys) in this analysis. Leptin was negatively associated with lumbar spine bone mineral content (β=-0.162, p=0.053). No significant interaction was found for muscular fitness. Simple slope estimates suggested that children performing more than 133.3kg in leg press test ameliorated the negative association between leptin and lumbar spine bone mineral content.

CONCLUSION

Leptin levels were negatively associated with lumbar spine bone mineral content in children with overweight or obesity. A high muscular fitness at the lower body could counteract this association.

Bone mineral density and body composition in normal weight, overweight and obese children

BACKGROUND

There is a possibility that excess body fat affects bone mass gain and may compromise skeletal health in obese children. The purpose of the study was to identify the relationship between bone mineral density (BMD) and body composition in normal weight, overweight and obese children.

METHODS

This was a cross-sectional study of 6- to 11-year-old children who attended the hospital's outpatient clinic. They were apparently healthy and had no history of prematurity, low birth weight, or chronic diseases. Body mass index (BMI) was used to identify subjects as normal weight, overweight or obese. BMD and body composition were assessed by dual energy X-ray absorptiometry. The BMD values (total and lumbar spine) were compared between normal weight, overweight and obese children. Correlation coefficients were calculated, and multivariate models were performed.

RESULTS

Forty-nine children were included: 16 with normal weight, 15 that were overweight and 18 with obesity; the mean age was 8.4 ± 1.7 years. All the participants had a normal BMD (> - 2 SD). BMD was higher in obese children and had a positive correlation with total and trunk lean mass in the three study groups (p < 0.001). In obese children, an inverse correlation of lumbar spine BMD (Z score) with total and trunk fat mass (p < 0.05) was identified. In the multivariate models (with the whole group), the total lean mass was the only significant variable that explained BMD variability.

CONCLUSIONS

BMD in obese children was higher than that in normal weight children, which is explained by their greater lean mass and not by excess body fat. In obese children, a higher fat mass was related to a lower lumbar spine BMD. Lean mass had a direct correlation with BMD in the three study groups and was the most important predictor of BMD, reflecting the importance of strengthening the muscular system through performing physical activity and practicing a healthy lifestyle.

High-sensitivity C-reactive protein could be a potential indicator of bone mineral density in adolescents aged 10-20 years

There was very limited evidence linking high-sensitivity C-reactive protein (HS-CRP) and total bone mineral density (BMD) in adolescents. The aim of this population-based study was to investigate the relationship between HS-CRP and total BMD in adolescents aged 10-20 years. A cross-sectional study was performed in the normal U.S. population from the data of the National Health and Nutrition Examination Survey (NHANES). The correlation between HS-CRP and total BMD was evaluated by using weighted multivariate linear regression models. And further subgroup analysis was conducted. There were 1747 participants in this study, 47.1% were female, 29.4% were white, 19.5% were black, and 22.3% were Mexican-American. In the multi-regression model that after the potential confounders had been adjusted, HS-CRP was negatively associated with total BMD. The negative association was also observed in the subgroup analyses stratified by gender and age. Our results demonstrated that higher HS-CRP was negatively correlated with total BMD in 10-20 years old adolescents.

Early Life Factors Associated with Lean Body Mass in Spanish Children: CALINA Study

Early life is critical for the programming of body composition. The literature links perinatal factors with fat mass development and its future effects (e.g., obesity); however, little evidence exists between early life factors and lean body mass (LBM). This study follows up on a cohort of 416 Spanish children at ages six to eight, previously evaluated at birth in the CALINA study. Here, we studied the association between early life factors, LBM, and limb strength. Parental origin/nutritional status, maternal smoking during pregnancy, gestational diabetes/weight gain/age, birth weight (BW), early feeding, and rapid weight gain (RWG) were collected from primary care records. Bioimpedance analysis, dual-energy X-ray absorptiometry, peripheral quantitative computed tomography, and a handgrip/standing long jump test were used to assess fat-free mass index (FFMI), total lean soft tissue mass index (TLSTMI), muscle cross-sectional area index (MCSAI), and limb strength, respectively. In girls, maternal smoking, gestational age, and BW were positively associated with FFM/LSTM. In boys, the parents’ BMI, BW, and RWG were positively associated with FFM/LSTM. BW was associated with handgrip strength in both. Maternal BMI in girls and RWG in boys were negatively associated with the standing long jump. Early life programming plays a key role in determining LBM in children.

Effects of aerobic exercise combined with resistance training on health-related physical fitness in adolescents: A randomized controlled trial

Background

/Objective: This study aimed to compare the effects of two combined training methods on health-related physical fitness components in adolescents.

Methods

Seventy-six adolescents (16.1 ± 1.1 years, n = 44 female) were randomized into groups of moderate-intensity continuous training combined with resistance training (MICT + RT), high-intensity interval training combined with resistance training (HIIT + RT), or Control. The training sessions were performed twice weekly for 12 weeks. The health-related physical fitness components evaluated were: body composition, muscular and cardiorespiratory fitness.

Results

The intervention groups had a significant reduction in body fat percentage and improvement in abdominal repetitions and VO_2peak after 12 weeks of combined exercise program (p < 0.001). Intervention effects were found to significantly reduce body fat percentage for the MICT + RT and HIIT + RT groups compared to the control group (mean difference: −3.8; 95% CI: −6.2; −1 0.3; mean difference: −4.7; 95%CI: −7.1; −2.3, respectively). For muscle fitness, significant effects of the intervention were found in increasing the number of abdominal repetitions favoring the MICT + RT group compared to the control group (mean difference: 9.5; 95% CI: 4.4; 14.7) and HIIT + RT compared to the control group (mean difference: 14.1; 95% CI 9; 19.3). For cardiorespiratory fitness, significant effects of the intervention on improving VO_2peak were found in the experimental groups (MICT + RT vs Control group: mean difference: 4.4; 95% CI: 2.2; 6.6; and HIIT + RT vs. Control group: mean difference: 5.5, 95% CI: 3.3; 7.7).

Conclusion

The results suggest that 12 weeks of training using MCIT + RT or HIIT + RT showed a similar effect for health-related physical fitness components in adolescents.

Body composition in preschool children with short stature: a case-control study

Background

Short stature is defined as height below 2 standard deviations of the population with the same age, gender. This study is aimed to assess the characteristics of body composition in preschool children with short stature.

Methods

Anthropometric measurements and body composition were assessed in 68 preschool children aged 3 to 6 years old with short stature and 68 normal controls matched on age and gender. Height, weight and body composition (total body water, protein, minerals, body fat mass, fat-free mass, soft lean mass, skeletal muscle mass, and bone mineral contents) in the two groups were measured and compared.

Results

The total body water, protein, minerals, body fat mass, fat-free mass, soft lean mass, skeletal muscle mass, and bone mineral contents were lower in preschool children with short stature than controls (P < 0.05). Body mass index and fat mass index did not differ between groups. Fat-free mass index was significantly lower in short stature group than controls (t = 2.17, P = 0.03). Linear regression analysis showed that there was a positive correlation between height and fat-free mass index [β, 1.99 (0.59, 3.39), P = 0.01], a negative correlation between height and body fat percentage [β, − 0.20 (− 0.38, − 0.01), P = 0.04]. The proportions of fat-free mass in the upper limbs were significantly lower (Right,t = − 2.78,Left t = − 2.76, P < 0.05, respectively) in short stature, although body fat distribution was not.

Conclusions

The fat-free mass such as protein and bone minerals is lower in preschool children with short stature, suggesting the monitoring of fat-free mass for early identification and intervention.

Relationship Between Muscle Strength, Body Composition and Bone Mineral Density in Adolescents

Adolescence is an important period for the acquisition of bone mass, which can be enhanced by several factors. This study aimed examine the relationships of handgrip strength, free-fat mass, and fat mass with bone mineral density in adolescents. 118 adolescents (60 girls), aged 10 to 14 years, participated in the study. Information on sex, age, handgrip strength, free-fat mass, fat mass and bone mineral density were collected. Multiple linear regression analyses were conducted to examine possible relationships between bone mineral density and handgrip strength, free-fat mass and fat mass. There was a relation between handgrip strength and free-fat mass with bone mineral density in both sexes. Fat mass was correlated with bone mineral density only in girls (r= 0.314, p< 0.014). The final models, adjusted for sexual maturation, included free-fat mass (girls - β= 0.419, p< 0.001; boys - β= 0.455; p< 0.001) and handgrip strength (girls - β= 0.358, p< 0.05; boys - β= 0.325; p< 0.05) and these variables together explained 51.8% and 62.9% of the variation of bone mineral density, in girls and boys, respectively. Handgrip strength and free-fat mass were positively associated with bone mineral density. A sex-specific difference indicated that higher levels of free-fat mass are of paramount importance for both sexes.

Moderate-to-Vigorous Physical Activity Is Associated With Higher Bone Mineral Density in Children With Inflammatory Bowel Disease

OBJECTIVES

Decreased mineral bone density (BMD) and reduced lean body mass (LBM) are common amongst children with inflammatory bowel disease (IBD). The aim of our cross-sectional, observational study was to evaluate the relationship between BMD, body composition and physical activity (PA) in children with IBD in remission.

METHODS

Total body less head (TLBH) dual energy X-ray absorptiometry (DXA) was used to measure BMD, fat mass (FM) and lean body mass (LBM). Triaxial accelerometer for five consecutive days was used to objectivize PA.

RESULTS

Forty pediatric IBD patients in clinical remission (24 boys; age 15.3 ± 0.4 years; Crohn disease [CD], n = 20, ulcerative colitis [UC], n = 18, inflammatory bowel disease-unclassified [IBD-U], n = 2) were recruited. Mean BMD was 0.940 g/cm2 and mean BMD z score was -0.42 ± 0.14. Patients with CD had significantly lower BMD than UC counterparts (P < 0.001). Average time spent in PA was 247.24 ± 16.71 min/day with 45.73 ± 8.22 min/day spent in moderate-to-vigorous PA (MVPA). We observed a significant positive correlation between the time spent in MVPA and BMD z score (P = 0.003) and LBM z score (P = 0.026). Multivariate analysis confirmed that the positive correlation of MVPA and BMD z score. There was no significant correlation between daily protein intake and BMD. Cumulative glucocorticoid dose negatively correlated with LBM z score (P = 0.003), but not with BMD z score (P = 0.069).

CONCLUSIONS

This study points to a strong positive relationship between MVPA, LBM and BMD. Longitudinal studies are required in order to elucidate the modifiable processes that determine body health and favorable body composition.

The Different Effects of Skeletal Muscle and Fat Mass on Height Increment in Children and Adolescents Aged 6-11 Years: A Cohort Study From China

OBJECTIVE

This study aimed to investigate the contribution of body composition including skeletal muscle mass (SMM) and body fat mass (BFM) to longitudinal growth among children and adolescents aged 6-11 years old.

METHODS

This cohort study was conducted from the annual health examination between 2019 and 2020. Annual height gain and weight gain and changes in SMM and BFM were calculated and compared between sexes, different nutritional status, and growth curve shifting mode. Spearman analyses and multiple linear regression analysis were performed to identify the impact of SMM, BFM, or body mass index (BMI) on height gain.

RESULTS

Of the 584 subjects, the annual height gains of boys (4.76 cm in the 6-9-year group and 4.63 cm in the 10-11-year group) were significantly lower than those of girls (5.48 and 5.74 cm, respectively). Spearman analysis showed that SMM gain and height gain were positively and significantly correlated in each examination of all children (r = 0.535 for boys and 0.734 for girls, p < 0.001). Conversely, BFM and height gains were negatively (r = -0.5240 for boys and -0.232 for girls, p < 0.001) correlated. Multiple linear regression analysis identified SMM gain as an independent predictor (95% CI: 1.20,1.44) of height gain after adjusting for age, gender, BMI, BFM gain, and percentage of body fat (PBF).

CONCLUSION

SMM gains, rather than BFM gains, were associated with height gains in children and adolescents aged 6-11 years. Monitoring SMM changes in routine healthcare might motivate children and adolescents to achieve dietary and exercise recommendations, thereby growing taller without gaining excessive weight.

Bone Response to High-Intensity Interval Training versus Moderate-Intensity Continuous Training in Adolescents with Obesity

INTRODUCTION

Since adolescents with obesity are prone to bone fragility during weight loss, the aim was to compare the impact of high-intensity interval training (HIIT) versus moderate-intensity continuous training (MICT) on bone density, geometry, and strength.

METHODS

Sixty-one adolescents were randomly assigned to 2 cycling trainings (HIIT and MICT) and a control (CTR, without training) group. Anthropometry, dual-energy X-ray absorptiometry with hip structural analysis and the trabecular bone score (TBS) were assessed before and after the 16-week intervention.

RESULTS

Body mass index (BMI) and fat mass (FM) percentage decreased at T1 versus T0 in both training groups (p < 0.001 for HIIT, p = 0.01 for MICT), though to a larger extent in HIIT (p < 0.05). Total body bone mineral density (BMD) and bone mineral content (BMC) increased in both training groups (p < 0.001), but to a greater extent in HIIT for BMC (p < 0.05). Lumbar spine BMD and BMC increased in both training groups (p < 0.001 for HIIT, p < 0.01 for MICT), with a time × group interaction between HIIT and CTR (p < 0.05) only. TBS increased in both training groups (p < 0.01 for HIIT, p < 0.05 for MICT). Hip BMD and BMC increased in both HIIT (p < 0.001 and p < 0.01) and MICT (p < 0.01 and p < 0.05). At the narrow neck (NN), endocortical diameter, width (p < 0.01), cross-sectional moment of inertia, and section modulus (Z) (p < 0.05) increased only in the HIIT group, such as BMD and Z (p < 0.05) at the intertrochanteric region (IT) and average cortical thickness (p < 0.001) and width (p < 0.05) at the femoral shaft. At the NN and IT, the buckling ratio decreased only in the HIIT group (p < 0.05), predicting higher resistance to fracture.

CONCLUSIONS

In addition to inducing greater BMI and FM percentage decreases in comparison to MICT, HIIT improves multisite bone density, geometry, and strength, which heighten the justification for HIIT as part of weight loss interventions in adolescents with obesity.

Low bone mass in Noonan syndrome children correlates with decreased muscle mass and low IGF-1 levels

Although musculoskeletal abnormalities have long been described in patients with Noonan syndrome (NS), only a few studies have investigated the bone status of these patients. The aim of this retrospective observational study was to describe the bone health of children with NS. Thirty-five patients with a genetically confirmed diagnosis of NS were enrolled. We analyzed the axial skeleton (lumbar spine) using dual energy X-ray absorptiometry and the appendicular skeleton (hand) with the BoneXpert system. Bone metabolism markers, including mineral homeostasis parameters, serum 25-hydroxy vitamin D (25-OHD) levels and markers of bone formation and resorption were also reported. Compared to the general population, axial and appendicular bone mass was significantly decreased in children with NS (p < 0.0001). Serum 25-OHD levels were low in about half of the patients and were negatively correlated with age (r = -0.52; p < 0.0001). Patients with NS exhibited reduced bone formation marker levels and increased bone resorption marker levels (p < 0.0001). No gender difference or genotype-phenotype correlations were found for the different bone parameters. Muscle mass and, to a lesser extent, serum insulin-like growth factor 1 (IGF-1) levels were independent predictors of whole-body bone mineral content (p < 0.0001 for both parameters; adjusted R² = 0.97). In conclusion, bone mass is reduced in children with NS and correlates with decreased muscle mass and low serum IGF-1 levels. These data justify addressing all potential threats to bone health including sufficient calcium and vitamin D intake, regular physical exercise, and hormone replacement therapy.

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

BACKGROUND

Relationships between the severity of obesity and bone health remain underexplored.

OBJECTIVES

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.

METHODS

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).

RESULTS

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.

CONCLUSIONS

Extreme obesity impacts bone health depending on anatomical sites, altering lumbar trabecular bone in both males and females adolescents.

Muscle-bone axis in children with chronic kidney disease: current knowledge and future perspectives

Bone and muscle tissue are developed hand-in-hand during childhood and adolescence and interact through mechanical loads and biochemical pathways forming the musculoskeletal system. Chronic kidney disease (CKD) is widely considered as both a bone and muscle-weakening disease, eventually leading to frailty phenotype, with detrimental effects on overall morbidity. CKD also interferes in the biomechanical communication between two tissues. Pathogenetic mechanisms including systemic inflammation, anorexia, physical inactivity, vitamin D deficiency and secondary hyperparathyroidism, metabolic acidosis, impaired growth hormone/insulin growth factor 1 axis, insulin resistance, and activation of renin-angiotensin system are incriminated for longitudinal uncoordinated loss of bone mineral content, bone strength, muscle mass, and muscle strength, leading to mechanical impairment of the functional muscle-bone unit. At the same time, CKD may also interfere in the biochemical crosstalk between the two organs, through inhibiting or stimulating the expression of certain osteokines and myokines. This review focuses on presenting current knowledge, according to in vitro, in vivo, and clinical studies, concerning the pathogenetic pathways involved in the muscle-bone axis, and suggests approaches aimed at preventing bone loss and muscle wasting in the pediatric population. Novel therapeutic targets for preserving musculoskeletal health in the context of CKD are also discussed.

Association between Body Composition and Bone Mineral Density in Children and Adolescents: A Systematic Review and Meta-Analysis

Background: Bone mass acquisition during growth is a major determinant of the risk of developing osteoporosis later in life. Body composition is an anthropometric determinant of bone mineral density (BMD) and significantly influences its development during childhood and adolescence. Objective: This study aimed to systematically examine the association between body composition and bone mineral density in children and adolescents. Methods: Observational studies addressing this association were identified from PubMed (MEDLINE), Embase, Scopus and the Cochrane Library (up to January 2021). The study populations consisted of healthy children and adolescents. The DerSimonian and Laird method was used to compute pooled estimates of effect size and the respective 95% confidence intervals for upper limbs, femoral neck (FN), lumbar spine (LS) and total body, respectively. Subgroup analyses were further performed based on age, sex and ethnicity. Results: Thirty-one published studies were eligible for inclusion in this systematic review and meta-analysis, including three longitudinal studies. The combined population from all the studies amounted to 21,393 (11,205 males and 10,188 females). The pooled estimates of the correlation coefficients for lean mass (LM) and BMD ranged from 0.53 to 0.74 (p < 0.050), and the pooled regression coefficients ranged from 0.23 to 0.79 for FN, LS and total body (p < 0.050). For fat mass (FM), the pooled correlation coefficients ranged from 0.10 to 0.50 (p < 0.050) and the pooled regression coefficient was only significant for FN BMD with a weak strength (pooled β = 0.07, p < 0.050). The pooled regression coefficients for body fat percentage (BF%) were between −0.54 and −0.04 (p < 0.050). The subgroup analysis revealed a stronger association in Asians than in Caucasians for LM and in males compared to females for BF% (p < 0.050). Conclusions: This systematic review and meta-analysis supports a positive association between LM and BMD. BF% appears to have a deleterious effect on bone acquisition in children and adolescents.

Associations between Spanish children's physical activity and physical fitness with lean body mass: The CALINA study

The present study investigated the associations between physical activity (PA) and physical fitness (PF) with lean body mass (LBM) and evaluated whether PA mediates the association between PF and LBM. 279 children (150 boys) aged 7.5 ± 0.3 years participated in the study. PA was assessed by accelerometry and PF with handgrip and the standing long jump test. Total lean soft tissue mass index (TLSTMI), muscle cross-sectional area index (MCSAI), and fat-free mass index (FFMI) were evaluated using dual-energy X-ray absorptiometry, peripheral quantitative computed tomography, and bioimpedance analysis, respectively.Total (β = 0.247) and vigorous PA (β = 0.143) were associated with TLSTMI in girls. In boys, total (β = 0.337), light (β = 0.290), vigorous (β = 0.200), and moderate-vigorous PA (β = 0.189) were associated with TLSTMI. Total PA was associated with FFMI (β = 0.299). Handgrip strength does not mediate the relationship between total PA and TLSTMI. Positive associations were found between handgrip strength and TLSTMI, MCSAI, and FFMI in both girls and boys.In children, there is a positive association between total and vigorous PA with TLSTMI. Handgrip strength does not mediate the relationship between total PA and TLSTMI. It was associated with TLSTMI, MCSAI, and FFMI.

Effects of anthropometric parameters on bone mineral density in women: from perimenopause to old age

AIM

To analyze the influence of body components on bone mineral density (BMD) in women from perimenopause to old age.

MATERIAL AND METHODS

A total of 117 women were allocated into three groups according to the reproductive stage (STRAW): perimenopausal (PEM, N = 28, mean age 44.8 ± 3.6), early postmenopausal (EPM, N = 36, mean age 51.4 ± 2.8) and late postmenopausal (LPM, N = 53; mean age 64.0 ± 1.7). Total body mass, body mass index (BMI), lean mass (LM), fat mass (FM), fat percentage (FP) and BMD at the lumbar spine (lBMD) and femoral neck (fBMD) were assessed.

RESULTS

BMI, FM, LM and BMD values decreased from PEM to LPM. The total effect of FM on fBMD and lBMD was of 42% and 8% for PEM, 28% and 33% for EMP and 9% and 1% for LPM respectively. Additionally, the total effect of LM on fBMD and lBMD was 48% and 3% for PEM, 54% and 53% for EMP and 9% and 11% for LPM women respectively.

CONCLUSION

BMI, LM, and FM decreased with aging. All these components had great influence on both fBMD and lBMD in EMP women. Conversely, in PEM these parameters only had influence on femoral BMD, but not on lumbar spine. These data suggests that LM is the most important component in BMD for women older than 50 years old, particularly in the hip.

Factors associated with bone health status of Malaysian pre-adolescent children in the PREBONE-Kids Study

Background

Modifiable lifestyle factors and body composition can affect the attainment of peak bone mass during childhood. This study performed a cross-sectional analysis of the determinants of bone health among pre-adolescent (N = 243) Malaysian children with habitually low calcium intakes and vitamin D status in Kuala Lumpur (PREBONE-Kids Study).

Methods

Body composition, bone mineral density (BMD), and bone mineral content (BMC) at the lumbar spine (LS) and total body (TB) were assessed using dual-energy X-ray absorptiometry (DXA). Calcium intake was assessed using 1-week diet history, MET (metabolic equivalent of task) score using cPAQ physical activity questionnaire, and serum 25(OH) vitamin D using LC-MS/MS.

Results

The mean calcium intake was 349 ± 180 mg/day and mean serum 25(OH)D level was 43.9 ± 14.5 nmol/L. In boys, lean mass (LM) was a significant predictor of LSBMC (β = 0.539, p < 0.001), LSBMD (β = 0.607, p < 0.001), TBBMC (β = 0.675, p < 0.001) and TBBMD (β = 0.481, p < 0.01). Height was a significant predictor of LSBMC (β = 0.346, p < 0.001) and TBBMC (β = 0.282, p < 0.001) while fat mass (FM) (β = 0.261, p = 0.034) and physical activity measured as MET scores (β = 0.163, p = 0.026) were significant predictors of TBBMD in boys. Among girls, LM was also a significant predictor of LSBMC (β = 0.620, p < 0.001), LSBMD (β = 0.700, p < 0.001), TBBMC (β = 0.542, p < 0.001) and TBBMD (β = 0.747, p < 0.001). Calcium intake was a significant predictor of LSBMC (β = 0.102, p = 0.034), TBBMC (β = 0.122, p < 0.001) and TBBMD (β = 0.196, p = 0.002) in girls.

Conclusions

LM was the major determinant of BMC and BMD among pre-adolescent Malaysian children alongside other modifiable lifestyle factors such as physical activity and calcium intake.

Analysis of the Association between Fat Mass Distribution and Bone Mass in Chinese Male Adolescents at Different Stages of Puberty

Background: Bone mineral acquisition during adolescence is crucial for maximizing peak bone mass. Fat mass (FM) and bone mass are closely related. This study investigated the association of FM distribution with bone mass in Chinese male adolescents. Method: A total of 693 male adolescents aged 10–18 years were recruited from a secondary school in Jiangmen, China. Their bone mass and body composition were measured by quantitative ultrasound and bioelectrical impedance analysis, respectively. The associations of the measures of fat distribution with bone parameters, i.e., broadband ultrasound attenuation, speed of sound (SOS), and stiffness index (SI), were analyzed using multiple linear regression. Age, height, body mass index, stage of puberty, physical activity, sedentary behavior, dietary energy intake, and dietary calcium and vitamin D intake were adjusted in the model. Further subgroup analyses of prepubertal and pubertal participants were conducted. Results: The measures of fat distribution showed negative associations with SOS and SI in total subjects (p < 0.010). In prepubertal boys, the measures of fat distribution were only associated with SOS (β = −0.377 to −0.393, p < 0.050). In pubertal boys, the measures of fat distribution had associations with all bone parameters (β = −0.205 to −0.584, p < 0.050). The strongest association was between trunk FM and SOS (β = −0.584, p < 0.001). Conclusion: This study supported that the measures of fat distribution were negatively associated with bone parameters in Chinese male adolescents. Trunk FM had the strongest association with bone parameter. These associations appear to be stronger in pubertal boys than in prepubertal boys.

Relationship Between Bone Mineral Density and Body Composition According to Obesity Status in Children

OBJECTIVE

To analyze the relationship between body composition, metabolic parameters, and bone mineral density (BMD) according to sex and the degree of obesity in children and adolescents.

METHODS

A total of 236 subjects with obesity, aged 10 to 15 years (36.9% girls), were enrolled. Obesity was classified into simple (SmOb) and extreme (ExOb) forms. The BMD of the total body, less head, was measured by dual energy x-ray absorptiometry, and the BMD z-score was used to evaluate the relationship of body composition with metabolic parameters.

RESULTS

BMD z-scores were higher in subjects with ExOb than in those with SmOb. Lean mass index (LMI), body mass index z-score, and vitamin D intake showed positive relationships, whereas percentage of body fat and serum leptin level showed negative relationships with BMD z-scores in boys. In girls, LMI and body mass index z-score showed positive relationships with BMD z-scores. In multivariable linear regressions, serum leptin level showed negative relationships with BMD z-score, only in boys. In addition, positive relationships of LMI and negative relationships of percentage of body fat with BMD z-scores were observed in subjects with SmOb. However, positive relationships of LMI with BMD z-scores were attenuated in subjects with ExOb.

CONCLUSION

High BMD appears to be positively associated with lean mass in children and adolescents with obesity, which might be a natural protective mechanism to withstand the excess weight. However, excessive body fat appears to be negatively associated with BMD, which might attenuate the positive relationship between lean mass and BMD in subjects with ExOb.

Non-linear association of body composition and its components with bone density in Iranian children and adolescents

Peak bone mass is established during childhood. This study aimed to evaluate the associations of the components of overall body mass with areal bone mineral density Z-score in children. The findings of this study showed that children with greater overall body mass had higher aBMD Z-score.

PURPOSE

Peak bone mass is established during childhood and adolescence. One of the important factors influencing predicted bone mass tracking in childhood and adolescence is alteration in the body composition during this growth period. This study aimed to evaluate the associations of the components of overall body mass with areal bone mineral density Z-score in children and adolescents.

METHODS

In this cross-sectional study, 478 healthy Iranian children and adolescents (237 girls and 241 boys) who had DXA measures participated. We evaluated the linearity of associations using generalized additive models.

RESULTS

Children's mean age was14 years with a range of 9-18 years, and 49.6% were girls. We found an increase in aBMD Z-score with increasing overall body mass (r = 0.25, p < 0.001). We observed this association with fat-free mass and total fat mass up to the 60th (~30 Kg) and 75th percentile (~12.5 Kg) [0.051 (95% CI, 0.027-0.075) increase in aBMD Z-score per 1 Kg increase in fat-free mass and 0.079 (95% CI, 0.044-0.114) increase in aBMD Z-score per 1 Kg increase in the total fat mass]. The correlation between Z-score of overall body mass and its components with aBMD Z-score was strongly positive. (P value < 0.001 for all) CONCLUSION: The findings of this study showed that children with greater overall body mass had higher aBMD Z-score. In addition, this study adds to a growing literature, suggesting that the relationship between body composition and BMD may be influenced by the pattern of fat and fat-free mass distribution in population.

Influence of weight status on bone mineral content measured by DXA in children

INTRODUCTION

Childhood obesity is a public health problem with repercussions in later life. As tissue formation peaks in childhood we determined how weight status influences bone mineral content.

MATERIAL AND METHODS

We studied 553 children aged 4-18 years over 10 years (46.8% girls). We measured age, weight, height and through bone densitometry (DXA), bone mineral content (BMC), bone mineral density (BMD), and waist, arm and hip circumferences. The patients were divided into groups using the body mass index z-score: underweight, normal weight, overweight, obese and very obese.

RESULTS

BMC and BMD values were highest in the normal-weight and overweight groups. Logistic regression showed bone mineralization was inversely associated with waist circumference, the association being positive for weight and age. No differences were found according to sex.

DISCUSSION

Studies of the relationship between weight and bone mineralization report contradictory results, often because of different study designs. Moreover, studies in children are either few or with small samples. Our findings in a large sample show the importance of weight status in bone mineralization given the risk of bone fractures or osteoporosis.

CONCLUSIONS

Weight status influenced bone mineralization. BMC and BMD decreased in children with a higher degree of obesity. Waist circumference correlated negatively with bone mineralization.

Promoting bone health in children and adolescents following solid organ transplantation

Solid organ transplantation in children and adolescents provides many benefits through improving critical organ function, including better growth, development, cardiovascular status, and quality of life. Unfortunately, bone status may be adversely affected even when overall status is improving, due to issues with pre-existing bone disease as well as medications and nutritional challenges inherent post-transplantation. For all children and adolescents, bone status entering adulthood is a critical determinant of bone health through adulthood. The overall health and bone status of transplant recipients benefits from attention to regular physical activity, good nutrition, adequate calcium, phosphorous, magnesium and vitamin D intake and avoidance/minimization of soda, extra sodium, and obesity. Many immunosuppressive agents, especially glucocorticoids, can adversely affect bone function and development. Minimizing exposure to "bone-toxic" medications is an important part of promoting bone health in children post-transplantation. Existing guidelines detail how regular monitoring of bone status and biochemical markers can help detect bone abnormalities early and facilitate valuable bone-directed interventions. Attention to calcium and vitamin D supplementation, as well as tapering and withdrawing glucocorticoids as early as possible after transplant, can provide best bone outcomes for these children. Dual-energy X-ray absorptiometry can be useful to detect abnormal bone mass and fracture risk in this population and newer bone assessment methods are being evaluated in children at risk for poor bone outcomes. Newer bone therapies being explored in adults with transplants, particularly bisphosphonates and the RANKL inhibitor denosumab, may offer promise for children with low bone mass post-transplantation.

Influence of Changes in Soft Tissue Composition on Changes in Bone Strength in Peripubertal Girls: The STAR Longitudinal Study

Obesity and osteoporosis remain two major public health concerns. Soft tissue composition and bone are interrelated; however, it is still not well understood how changes in adiposity during adolescence affect bone development. The aim of this study was to assess how changes in DXA-derived total body lean mass (TBLM) and total body fat mass (TBFM) associate with 2-year changes in bone outcomes at the 20% femur, 66% tibia, 66% radius, and 4% tibia, as measured by pQCT, during the years surrounding the onset of menarche in a cohort of 9- to 12-year-old (baseline) adolescent girls (70% Hispanic). From baseline to 2-year follow-up, girls showed statistically significant increases in all bone outcomes, except radial endosteal circumference. In separate linear regression models, change in TBLM and change in TBFM were both positively associated with 2-year changes in bone outcomes at all measured bone sites, after controlling for relevant covariates. However, when change in TBLM and change in TBFM were included in the same model, change in TBLM was the predominant predictor of bone outcomes, explaining 4% to 14% of the variance in bone strength outcomes. Change in TBFM remained a positive predictor of tibia polar strength strain index (SSI_p) (2% variance explained). A significant interaction between change in TBFM and menarcheal status was identified at the radius for SSI_p and indicated that greater gains in TBFM were beneficial for SSI_p in girls that were premenarcheal at baseline but detrimental for girls who were postmenarcheal at baseline. The overall findings suggest that changes in TBLM during the peripubertal years have a greater influence on bone outcomes than changes in TBFM. While gains in TBFM might benefit the weight bearing 66% tibia, greater gains in TBFM may be detrimental to bone development at the non-weight bearing 66% radius after the onset of menarche. © 2020 American Society for Bone and Mineral Research (ASBMR).

Bone response to eccentric versus concentric cycling in adolescents with obesity

OBJECTIVES

Because adolescents with obesity are susceptible to bone fragility during weight loss (WL), we evaluated the impact of eccentric (ECC) versus classical concentric (CON) training at the same oxygen consumption (V˙O₂) on bone density, geometry and strength.

METHODS

Thirty five adolescents were included into 2 training (CON and ECC cycling) and a control (CTR, without training) groups. Anthropometry, dual-energy X-ray absorptiometry, hip structural analysis and quantitative bone ultrasound were assessed before and after the 12-week intervention.

RESULTS

The trainings promoted significant improvements in body mass index, total fat (FM) and lean mass (LM), with better improvements for FM and LM in the ECC group (p < 0.05). Leg LM percentage increased only in the ECC group (p < 0.05). Total body bone mineral content and density increased in both training groups (p < 0.001) with significant time x group interactions only between ECC and CTR (p < 0.05). Buckling ratio at the intertrochanteric region and femoral shaft increased only in CTR and CON groups (p < 0.05). Speeds of sounds at the calcaneum increased only in ECC group (p < 0.01).

CONCLUSIONS

Bone fragility, from a compromised relationship between density, geometry and strength, might be prevented with the ECC modality.

Association of objectively measured physical activity and bone health in children and adolescents: a systematic review and narrative synthesis

The influence of day-to-day physical activity on bone in adolescence has not been well characterized. Forty articles were identified that assessed the relationship between accelerometry-derived physical activity and bone outcomes in adolescents. Physical activity was positively associated with bone strength in peri-pubertal males, with less consistent evidence in females. Physical activity (PA) is recommended to optimize bone development in childhood and adolescence; however, the influence of day-to-day PA on bone development is not well defined. The aim of this review was to describe the current evidence for objectively measured PA on bone outcomes in healthy children and adolescents. MEDLINE, Embase, Cochrane Library, Scopus, Web of Science, CINAHL, PsycInfo, and ClinicalTrials.gov were searched for relevant articles up to April 2020. Studies assessing the relationship between accelerometry-derived PA and bone outcomes in adolescents (6-18 years old) were included. Two reviewers independently screened studies for eligibility, extracted data, and rated study quality. Forty articles met inclusion criteria (25 cross-sectional, 15 longitudinal). There was significant heterogeneity in accelerometry methodology and bone outcomes measured. Studies in males indicated a significant, positive relationship between moderate to vigorous PA (MVPA) and bone outcomes at the hip and femur, particularly during the peri-pubertal years. The results for MVPA and bone outcomes in females were mixed. There was a paucity of longitudinal studies using pQCT and a lack of data regarding how light PA and/or impact activity influences bone outcomes. The current evidence suggests that objectively measured MVPA is positively associated with bone outcomes in children and adolescents, especially in males. However, inconsistencies in methodology make it difficult to determine the amount and type of PA that leads to favorable bone outcomes. Given that the majority of research has been conducted in Caucasian adolescents, further research is needed in minority populations.

Association between sedentary behavior and bone mass in adolescents

The effects of sedentary behavior on adolescents' bone health are controversial because, even in normal weight individuals, the excessive time spent in some specific types of these behaviors appears to have no negative effect on bone health.

PURPOSE

To analyze the relationship between sedentary behaviors and bone mass in adolescents.

METHODS

One hundred four adolescent boys and girls, aged 10 to 14 years, were divided into normal weight and overweight according to weight status. Specific sedentary behaviors (time spent on the Internet for school and non-school purposes, using the computer, watching television, and playing videogames) were assessed by questionnaire, and the total sedentary behavior time by accelerometry. Bone parameters were collected using X-ray absorptiometry, using total and lumbar bone mineral density (BMD) and total and lumbar bone mineral content (BMC) values.

RESULTS

In both groups, the time spent on the Internet for non-school purposes was positively correlated to the total and lumbar BMD. Also, while in the overweight group, the time spent using the computer was negatively correlated to lumbar BMD, and the time spent on the Internet for non-school purposes was positively correlated to the total and lumbar BMC, and in the normal weight group, the time spent on the Internet for non-school purposes was positively correlated to lumbar BMC.

CONCLUSIONS

Adolescents who spend more time in sedentary behavior, especially using the Internet for non-school purposes, have higher BMD and BMC, while normal weight adolescents who spend more time on the computer have lower BMD.

A 24-Week Physical Activity Intervention Increases Bone Mineral Content without Changes in Bone Markers in Youth with PWS

Bone mineral density (BMD) is of concern in Prader-Willi syndrome (PWS). This study compared responses to a physical activity intervention in bone parameters and remodeling markers in youth with PWS (n = 45) and youth with non-syndromic obesity (NSO; n = 66). Measurements occurred at baseline (PRE) and after 24 weeks (POST) of a home-based active games intervention with strengthening and jumping exercises (intervention group = I) or after a no-intervention period (control group = C). Dual x-ray absorptiometry scans of the hip and lumbar spine (L1-L4) determined BMD and bone mineral content (BMC). Bone markers included fasting bone-specific alkaline phosphatase (BAP) and C-terminal telopeptide of type I collagen (CTx). Both I and C groups increased their hip BMD and BMC (p < 0.001). Youth with PWS-I increased their spine BMC from PRE to POST (p < 0.001) but not youth with PWS-C (p = 1.000). Youth with NSO (I and C) increased their spine BMC between PRE and POST (all p < 0.001). Youth with PWS showed lower BAP (108.28 ± 9.19 vs. 139.07 ± 6.41 U/L; p = 0.006) and similar CTx (2.07 ± 0.11 vs.1.84 ± 0.14 ng/dL; p = 0.193) than those with NSO regardless of time. Likely, the novelty of the intervention exercises for those with PWS contributed to gains in spine BMC beyond growth. Bone remodeling markers were unaltered by the intervention.

Bone Mineral Reference Values for Athletes 11 to 20 Years of Age

Objectives. Training for sport is associated with the development of bone minerals, and the need for reference data based on athletes is often indicated. The purpose of this study was to develop a reference for bone mineral density (BMD) and content (BMC) specific for youth athletes of both sexes participating in several sports. Methods DEXA (dual energy X-ray absorptiometry) was used for total body measurements of bone minerals in 1385 athletes 11 to 20 years, 1019 males and 366 females. The athletes were training in several sports at Hungarian academies. Reference values for total bone mineral density and bone mineral content, and also BMD excluding the head (total body less head, TBLH) were developed using the LMS chartmaker pro version 2.3. Results. The centile distributions for BMD and BMC of the athletes differed significantly from those of the age- and sex-specific references for the general population. The youth athletes had higher BMD and BMC than those of the reference for the general population. Conclusion. The potential utility of the DEXA reference for male and female youth athletes may assist in monitoring changes in the BMC and BMD associated with normal growth and maturation, and perhaps more importantly, may be useful in monitoring changes specific to different phases of sport-specific training protocols.

Bone Mineral Density of Femur and Lumbar and the Relation between Fat Mass and Lean Mass of Adolescents: Based on Korea National Health and Nutrition Examination Survey (KNHNES) from 2008 to 2011

It is most important to reach the maximum bone density in the childhood period to prevent developing osteoporosis; it is widely known that increased body weight has a positive correlation with bone density and that even though both the fat mass and lean mass have a significant impact on bone density, the latter mass has more importance for adults. Therefore, the study analyzed to identify the relationship between bone density and both fat mass and lean mass of Korean adolescents. Subjects were chosen among 21,303 people from the Korea National Health and Nutrition Examination Survey (KNHNES) between 2008 and 2011 that took a bone density checkup; as a result, 1454 teenagers aged between 12 and 18 were selected. Data analysis was performed in SAS ver. 9.4 (SAS Institute Inc., Cary, NC, USA) following the KNHNES and the weighted complex sample analysis was conducted; body fat mass and lean mass were divided into quintile groups, and to figure out the differences in bone density that were analyzed in six models adjusted by body weight (kg) and walking (yes/no), muscle strengthening exercises (yes/no), nutrition (intake of ca (g), and serum vitamin D (ng/mL)). Then, the generalized linear model (GLM) and trend test were conducted for each gender with a significance level of 0.05. The bone density differences of fat mass and lean mass were analyzed. The result of Model 6 considering all correction variables is as follows; in the case of male adolescents, the total femur and lumbar spine showed a significant difference (F = 13.120, p < 0.001; F = 12.900, p < 0.001) for fat mass, and the trend test showed that the figures significantly decreased (β = −0.030, p < 0.001; −0.035, p < 0.001). Meanwhile, for lean mass, the total femur and lumbar spine had a significant difference (F = 16.740, p < 0.001; F = 20.590, p < 0.001) too, but the trend test showed a significant increase (β = 0.054, p < 0.001; 0.057, p < 0.001). In the case of female adolescents, the lumbar spine (F = 3.600, p < 0.05) for lean mass showed a significant difference, and it also significantly rose in the trend test too (β = 0.020, p < 0.01). To sum up the results, for male adolescents, the bone density differences for fat mass (FM) and lean mass (LM) all had significant differences, but for female adolescents, only the lumbar spine for LM showed such a result. Meanwhile, both genders showed that LM had a more positive impact on bone density than FM.

Association of Serum Uric Acid Status With Bone Mineral Density in Adolescents Aged 12-19 Years

Aims: Evidence linking serum uric acid (sUA) and bone mineral density (BMD) in adolescents is very limited. To the best of our knowledge, only one report has focused on the relationship between sUA and BMD in adolescents. Thus, this study aimed to determine the association between sUA and total BMD in adolescents aged 12-19 years. Methods: A cross-sectional study was conducted on a sample composed of non-institutionalized US population from the National Health and Nutrition Examination Survey. Weighted multivariate linear regression models were used to evaluate the association between sUA and total BMD. Subgroup analyses were further performed. Results: sUA positively correlated with total BMD in the multiple regression model after adjusting for potential confounders. However, in the subgroup analyses stratified by sex, age, or race/ethnicity, the association between sUA and total BMD followed an inverted U-shaped curve in female adolescents, adolescents aged 16-19 years, and other race/ethnicity. Conclusions: Our results suggested that the correlation between sUA level and total BMD differed by sex. The increased sUA level would be beneficial to bone health in adolescents with low sUA levels, but for female adolescents, a higher sUA level (turning point, 3.9 mg/dL) may have an adverse effect on bone health.