Lumbar Spine Bone Mineral Apparent Density in Children: Results From the Bone Mineral Density in Childhood Study

Impact of growth hormone therapy on bone and body composition in prepubertal children with idiopathic short stature

OBJECTIVES

Few studies have investigated the effect of growth hormone (GH) therapy on bone health and body composition in children with idiopathic short stature (ISS). Therefore, this study aimed to evaluate the short-term effects of GH treatment on bone mineral density (BMD) and prepubertal body composition in children with ISS.

METHODS

The study included 53 prepubertal children with ISS (mean age, 6.3 ± 1.5 years). Their BMD was compared to that of 20 healthy prepubertal children matched for chronological age. Of the 53 children with ISS, 11 received GH therapy for 1 year. Anthropometric measurements and bone age assessments were conducted, and body composition was analyzed using dual-energy X-ray absorptiometry at 6-month intervals.

RESULTS

At baseline, lumbar spine and femoral neck BMD Z scores, adjusted for height, showed no significant differences between the ISS and control groups. However, bone mineral apparent density (BMAD) Z scores were significantly lower in children with ISS compared to controls. Over 12 months of GH therapy, no significant changes were observed in lumbar spine or femoral neck height-adjusted BMD Z scores. Nevertheless, GH treatment led to a significant reduction in percent body fat for chronological age and an increase in lean body mass after 1 year.

CONCLUSIONS

Prepubertal children with ISS exhibited lower BMAD at the lumbar spine compared to healthy controls. Although short-term GH therapy did not significantly alter bone density, it positively impacted body composition. These findings provide valuable clinical insights into bone health and body composition in children with ISS.

Association between pubertal timing and bone and body composition in young adult men

Bone and muscle development are important processes in pubertal maturation. The aim of this study was to investigate associations between pubertal timing and bone density and body composition in young adult men. In this observational study, bone and body composition was cross-sectionally assessed by dual-energy X-ray absorptiometry in 2056 healthy young men with median age 19, who retrospectively self-reported if they experienced pubertal changes at an earlier, similar or later age than their peers. Associations between voice break timing and bone and body composition were analyzed by linear regression. Men reporting earlier voice break than their peers (n = 417, 20%) had higher lumbar bone mineral density (BMD) and higher total body BMD. Apart from higher BMI, there were no differences in body composition. Men who reported later voice break (n = 353, 17%) had lower lumbar bone mineral content, bone area and volume, but similar BMD. They had lower BMI, lean mass and fat mass, resulting in a lower fat-to-muscle ratio. In conclusion, even after adult height has been reached, physiological variations in pubertal timing were associated with differences in bone and body composition in young adult men.

Analysis of cervical bone mineral density in children and adolescents using cone beam computed tomography combined with liquid phantoms

To describe cervical bone mineral density (BMD) in children and adolescents using Cone-beam Computed Tomography (CBCT) combined with K2HPO4 liquid phantoms. Children and adolescents aged 7-19 years who underwent CBCT for orthodontic treatment in our imaging department between January 2023 and June 2023 were selected. The CT values of the second (C2) and third (C3) cervical vertebrae were measured using the software supplied with the CBCT. K2HPO4 liquid phantoms were prepared according to standard protocols and scanned monthly. Regression equations were established between BMD values and CT values. The BMD values of C2 and C3 were then calculated and subsequently analyzed. A total of 455 children and adolescents participated in the study. The BMD values for females were found to be significantly higher than those for males across all age groups (P < 0.05). When comparing the BMD values between C2 and C3, a statistically significant difference was observed (P < 0.05). Furthermore, there were notable variations in the BMD values of C3 among females across different age groups (P < 0.05). However, no significant differences were detected in the BMD values of C2 overall or in the BMD values of C3 among males across no significant differences were detected across different age groups (P > 0.05). The results of this study provide reference values for BMD of C2 and C3 using CBCT combined with liquid phantoms. These reference values, obtained from healthy individuals, enable the assessment of BMD for systemic bone metabolism, orthodontics, implants, and tooth extraction, providing significant economic and social benefits.

The assessment of bone health in children with juvenile idiopathic arthritis; comparison of different imaging-based methods

BACKGROUND

Osteoporosis is increasingly being recognized in children, mostly secondary to systemic underlying conditions or medication. However, no imaging modality currently provides a full evaluation of bone health in children. We compared DXA, a radiographic bone health index (BHI (BoneXpert) and cone-beam CT for the assessment of low bone mass in children with juvenile idiopathic arthritis (JIA).

METHODS

Data used in the present study was drawn from a large multicentre study including 228 children aged 4-16 years, examined between 2015 and 2020. All had a radiograph of the left hand, a DXA scan and a cone-beam CT of the temporomandibular joints within four weeks of each other. For the present study, we included 120 subjects, selected based on DXA BMD and BoneXpert BHI to secure values across the whole range to be tested.

RESULTS

One hundred and twenty children (60.0% females) were included, mean age 11.6 years (SD 3.1 years). There was a strong correlation between the absolute values of BHI and BMD for both total body less head (TBLH) (r = 0.75, p < 0.001) and lumbar spine (L1-L4) (r = 0.77, p < 0.001). The correlation between BHI standard deviation score (SDS) and BMD TBLH Z-scores was weak (r = 0.34) but significant (0 = 0.001), varying from weak (r = 0.31) to moderate (r = 0.42) between the three study sites. Categorizing BHI SDS and DXA BMD Z-scores on a 0-5 scale yielded a weak agreement between the two for both TBLH and LS, with w-kappa of 0.2, increasing to 0.3 when using quadratic weights. The agreement was notably higher for one of the three study sites as compared to the two others, particularly for spine assessment, yielding a moderate kappa value of 0.4 - 0.5. For cone-beam CT, based on a 1-3 scale, 59 out of 94 left TMJ's were scored as 1 and 31 as score 2 by the first observer vs. 87 and 7 by the second observer yielding a poor agreement (kappa 0.1).

CONCLUSIONS

Categorizing DXA LS and automated radiographic Z-scores on a 0-5 scale gave a weak to moderate agreement between the two methods, indicating that a hand radiograph might provide an adjuvant tool to DXA when assessing bone health children with JIA, given thorough calibration is performed.

Growth hormone and testosterone delay vertebral fractures in boys with muscular dystrophy on chronic glucocorticoids

Glucocorticoid use in Duchenne and Becker muscular dystrophy prolongs ambulation but cause significant skeletal toxicity. Our analysis has immediate clinical implications, suggesting that growth hormone and testosterone have a stronger effect prior to first and subsequent vertebral fracture, respectively, relative to bisphosphonates alone in children with dystrophinopathies on chronic glucocorticoids.

PURPOSE

Glucocorticoids prolong ambulation in boys with Duchenne muscular dystrophy; however, they have significant endocrine side effects. We assessed the impact of growth hormone (GH), testosterone, and/or zoledronic acid (ZA) on vertebral fracture (VF) incidence in patients with dystrophinopathies on chronic glucocorticoids.

METHODS

We conducted a longitudinal retrospective review of 27 males with muscular dystrophy. Accelerated failure time (AFT) models were used to estimate the relative time to VF while on GH, testosterone, and/or ZA compared to ZA alone. Results are reported as failure time ratio, where >1 indicates prolonged time versus <1 indicates shorter time to next VF.

RESULTS

The prevalence of growth impairment was 96% (52% utilized GH), pubertal delay was 86% (72% utilized testosterone), and low trauma fractures were 87% (72% utilized ZA). Multivariable analysis of the AFT models showed that participants on either GH or testosterone treatment relative to ZA alone experienced prolonged time to next VF (1.253, P<0.001), with GH being the significant contributor when analyzed independently from testosterone (1.229, P<0.001). Use of ZA with GH or testosterone relative to ZA alone resulted in prolonged time to next VF (1.171, P<0.001), with testosterone being a significant contributor (1.130, P=0.033).

CONCLUSION

GH and testosterone each decreased VF risk in patients independent of or in combination with ZA, respectively.

A practical guide to the diagnosis and management of osteoporosis in childhood and adolescence

Osteoporosis in childhood distinguishes itself from adulthood in four important ways: 1) challenges in distinguishing otherwise healthy children who have experienced fractures due to non-accidental injury or misfortunate during sports and play from those with an underlying bone fragility condition; 2) a preponderance of monogenic "early onset" osteoporotic conditions that unveil themselves during the pediatric years; 3) the unique potential, in those with residual growth and transient bone health threats, to reclaim bone density, structure, and strength without bone-targeted therapy; and 4) the need to benchmark bone health metrics to constantly evolving "normal targets", given the changes in bone size, shape, and metabolism that take place from birth through late adolescence. On this background, the pediatric osteoporosis field has evolved considerably over the last few decades, giving rise to a deeper understanding of the discrete genes implicated in childhood-onset osteoporosis, the natural history of bone fragility in the chronic illness setting and associated risk factors, effective diagnostic and monitoring pathways in different disease contexts, the importance of timely identification of candidates for osteoporosis treatment, and the benefits of early (during growth) rather than late (post-epiphyseal fusion) treatment. While there has been considerable progress, a number of unmet needs remain, the most urgent of which is to move beyond the monotherapeutic anti-resorptive landscape to the study and application of anabolic agents that are anticipated to not only improve bone mineral density but also increase long bone cross-sectional diameter (periosteal circumference). The purpose of this review is to provide a practical guide to the diagnosis and management of osteoporosis in children presenting to the clinic with fragility fractures, one that serves as a step-by-step "how to" reference for clinicians in their routine clinical journey. The article also provides a sightline to the future, emphasizing the clinical scenarios with the most urgent need for an expanded toolbox of effective osteoporosis agents in childhood.

Using bone mineral apparent density for BMD adjustment in chronic diseases: Thalassemia an example

Background

Low BMD is a common problem in major thalassaemia patient, but the use of DXA in chronic disease children with smaller bones, has some problems. Utilizing bone mineral apparent density (BMAD) helps in preventing this obstacle. Testing the usefulness of this method in resolving the effects of bone size on BMD by comparing the BMD and BMAD of our thalassemics with results of our healthy ones, is our goal.

Methods

Sample size was 110 cases with mean age of 9.6 ± 4.3 y/o and contained 73 males. Gauge of BMDs done by dual x-ray absorptiometry. Then BMAD was calculated. We did comparison of BMDs and BMADs results of thalassemic children with results of healthy Iranian pediatrics.

Results

Mean of femoral BMD and BMAD, spinal BMD and BMAD was 0.579±0.134 g/cm2, 0.162±0.096 g/cm3, 0.563±0.118 g/cm2 and 0.107±0.015, respectively. When results of 9-18 patients compared with BMDs and BMADs of normal children, BMD of femur and BMD and BMAD of spine of patients found significantly lower (P-values, 0.003, <0.001, <0.001, respectively). BMAD of femur of patients was not significantly different from normals.

Conclusion

When bone mineral density of femur modifies by bone mineral apparent density formula, the remarkable difference between BMD of patients and normals; vanishes. Utilizing bone mineral apparent density helps in interpretation of femoral dual X-ray absorptiometry at least in thalassemic patients. As the results of vertebrae, after modification by calculating BMAD, remains significantly different, we cannot bring forward BMAD for mentioned aim in the spine of thalassemics.

Reference ranges for body composition indices by dual energy X-ray absorptiometry from the Bone Mineral Density in Childhood Study Cohort

BACKGROUND

Body composition assessment aids evaluation of energy stores and the impact of diseases and interventions on child growth. Current United States pediatric reference ranges from the National Health and Nutrition Examination Survey (NHANES) include 20% of children with obesity, body mass index of ≥95th percentile.

OBJECTIVES

This study aimed to develop dual energy X-ray absorptiometry (DXA) based reference ranges in a diverse cohort with low-obesity prevalence from the Bone Mineral Density in Childhood Study (BMDCS).

METHODS

This is a secondary analysis of a longitudinal, prospective, observational cohort. Healthy children (height and BMI within 3rd to 97th percentiles, ages 5-19 y at enrollment), from 5 United States centers were measured annually for ≤7 visits. Whole body scans were acquired using Hologic scanners. A subsample underwent repeat measurements to determine precision. We generated reference ranges for appendicular and total lean soft tissue mass index (LSTM Index), fat mass index (FMI), and other body composition measures. Resulting curves were compared to NHANES and across subgroups. Sex and age-specific equations were developed to adjust body composition Z-scores for height Z score.

RESULTS

We obtained 9846 scans of 2011 participants (51% female, 22% Black, 17% Hispanic, 48% White, 7% Asian/Pacific Islander, and 6% with obesity). Precision (percent coefficient of variation) ranged from 0.7% to 1.96%. Median and-2 standard deviation curves for BMDCS and NHANES were similar, but NHANES +2 standard deviation LSTM Index and FMI curves were distinctly greater than the respective BMDCS curves. Subgroup differences were more extreme for appendicular LSTM Index-Z (mean ± SD: Asian -0.52 ± 0.93 compared with Black 0.77 ± 0.87) than for FMI-Z (Hispanic 0.29 ± 0.98 compared with Black -0.14 ± 1.1) and were smaller for Z-scores adjusted for height Z-score.

CONCLUSIONS

These reference ranges add to sparse normative data regarding body composition in children and adolescents and are based on a cohort with an obesity prevalence similar to current BMI charts. Awareness of subgroup differences aids in interpreting results.

Evaluation of the trabecular bone score in 35 children and adults with X-linked hypophosphatemic rickets

INTRODUCTION

 The aim of this study is to evaluate and compare the trabecular bone scores (TBSs) of 11 children and 24 adults with X-linked hypophosphatemic rickets (XLH) and non-XLH subjects from a tertiary center.

MATERIALS AND METHODS

 The areal bone mineral density at the lumbar spine (LS-aBMD) and LS-aBMD Z score were analyzed by dual-energy X-ray absorptiometry. The bone mineral apparent density (BMAD) and LS-aBMD Z score adjusted for height Z score (LS-aBMD-HAZ) were calculated. The TBS was determined using TBS iNsight software based on DXA images from the Hologic QDR 4500 device.

RESULTS

The XLH patients exhibited a higher mean LS-aBMD Z score, BMAD, and TBS than the non-XLH subjects (p < 0.01). LS-aBMD-HAZ and BMAD were greater in the XLH children than those in their corresponding non-XLH subjects (p < 0.01 and p = 0.02), and the XLH children trended toward a greater TBS (p = 0.06). The XLH adults had a higher LS-aBMD Z score, BMAD, and TBS than the non-XLH subjects (p < 0.01). When stratified by metabolic status according to the serum values of bone formation markers, compensated adult patients had a higher LS-aBMD Z score, BMAD, and TBS than non-XLH subjects (p < 0.01). Noncompensated patients had higher LS-aBMD Z scores and BMAD results than non-XLH subjects. However, TBS values did not differ statistically significantly between those groups (p = 0.45).

CONCLUSION

The higher LS-aBMD Z score, BMAD, and TBS result in the XLH patients compared to non-XLH subjects indicates an increased amount of trabecular bone within the lumbar spine, regardless of extraskeletal calcifications.

Bone health in avoidant/restrictive food intake disorder: a narrative review

BACKGROUND

Avoidant/restrictive food intake disorder (ARFID) is an eating/feeding disturbance characterized by severe food avoidance or restriction that results in faltering growth, nutritional deficiencies, dependence on formula supplementation, and/or significant psychosocial impairment. Compared to other eating disorders, ARFID is observed to have an earlier childhood onset and chronic course without intervention. Childhood represents a sensitive period for longitudinal growth and bone accrual, setting the stage for long-term health outcomes associated with longevity and quality of life, including risk for fracture and osteoporosis.

RESULTS

This narrative review discusses published scientific literature on bone health in individuals with ARFID by describing the current understanding of ARFID's effect on bone health, how common dietary constraints characteristic of ARFID may present unique risks to bone health, and the current clinical recommendations for bone health assessment. Reviewing what is known of clinical data from anorexia nervosa (AN) and similar cohorts, the chronicity and etiology of dietary restriction observed in ARFID are hypothesized to compromise bone health significantly. Although limited, examination of bone health in ARFID patients suggests children with ARFID tend to have shorter stature compared to healthy reference datasets and have lower bone density compared to healthy individuals, similar to those with AN. There remains a substantial knowledge gap in how ARFID may interrupt bone accrual during childhood and adolescence, and subsequent impact on attainment of peak bone mass and peak bone strength. The longitudinal effects of ARFID may be subtle and overlooked clinically in the absence of severe weight loss or growth stunting. Early identification and remediation of threats to bone mass accrual have significant personal and population-level implications.

CONCLUSION

For patients with ARFID, delayed identification and intervention to address feeding disturbances may have a long-lasting impact on various body systems and processes, including those relating to longitudinal growth and bone mass accrual. Further research employing rigorous prospective observational and/or randomized study designs are required to clearly define effects of ARFID, as well as clinical interventions aimed at addressing ARFID-related feeding disturbances, on bone accrual.

Early life organophosphate ester exposures and bone health at age 12 years: The Health Outcomes and Measures of the Environment (HOME) Study

BACKGROUND

No human studies have evaluated early life organophosphate ester (OPE) exposures with bone health outcomes, despite evidence of osteotoxicity.

OBJECTIVES

We assessed associations of urinary OPE metabolites measured across early life with areal bone mineral density (aBMD) and bone mineral content (BMC) at age 12 years.

METHODS

Among 223 mother-child dyads enrolled in the Health Outcomes and Measures of the Environment (HOME) Study, we quantified concentrations of bis-2-chloroethyl phosphate (BCEP), bis-(1,3-dichloro-2-propyl) (BDCIPP), di-n-butyl phosphate (DnBP), and diphenyl phosphate (DPHP) in urine collected from mothers during pregnancy and children at ages 1, 2, 3, 5, and 8 years. At age 12 years, we performed dual energy x-ray absorptiometry and calculated aBMD and BMC z-scores at six skeletal sites. We estimated overall and sex-stratified BMD/BMC z-score differences per interquartile range (IQR) increase in OPE concentrations at multiple exposure timepoints: gestation (average) and 1-3 (average), 5, and 8 years.

RESULTS

In adjusted models, overall associations of BCEP and BDCIPP with total hip and 1/3rd distal radius aBMD and BMC varied significantly by exposure timepoint, as did BDCIPP with whole body aBMD. For example, differences (95 % CI) in total hip aBMD z-score per IQR increase in BDCIPP were 0.33 (0.01, 0.64), -0.10 (-0.34, 0.14), -0.18 (-0.40, 0.05), and 0.14 (-0.09, 0.38) for concentrations during gestation and at 1-3, 5, and 8 years, respectively. Overall DnBP and DPHP associations were generally null at all timepoints. We observed sex-specific associations for some timepoints and skeletal sites. For example, an IQR increase in 8-year DPHP was associated with a 0.21 (0.05, 0.38) greater total hip aBMD z-score among females but -0.19 (-0.43, 0.05) lower z-score among males.

DISCUSSION

Early life OPE exposures may be associated with sex- and exposure period-dependent alterations in early adolescent bone mineral accrual and strength.

Reference values of bone mineral density of proximal femur for Southeast Asian children and adolescents

Bone mineral density (BMD) of the proximal femur helps evaluate bone density in children with reduced mechanical loading of the lower extremities. This study provides the first reference values of bone mineral density of proximal femur according to age and sex for Southeast Asian children and adolescents.   OBJECTIVES: The study aimed to (1) establish normative data of BMD of the proximal femur (femoral neck and total hip), measured by dual-energy X-ray absorptiometry (DXA), for healthy Thai children aged 5 to 18 years and (2) ascertain the relationships between BMD, growth, and puberty.

METHODS

Proximal femur scans of 170 boys and 191 girls obtained from DXA (Lunar Prodigy Pro, GE, and software enCORE version 7.53) were un-analyzed and then re-analyzed with the upgraded software enCORE version 17 SP2 for BMD assessment. The bone mineral apparent density of the femoral neck (FNBMAD) was calculated.

RESULTS

Sex and Tanner stage-specific BMD normative data were generated. BMD values of the femoral neck and total hip increased with age and pubertal progression. FNBMAD values were not markedly influenced by age and puberty. Using multiple linear regression analysis, age and weight affected FNBMD and total hip BMD in boys and girls, but height and Tanner stage only influenced girls. Age did not significantly influence FNBMAD in either sex. Tanner stage weakly influenced FNBMAD only in boys.

CONCLUSIONS

We established normative reference data for BMD of the proximal femur measured by DXA in Thai children aged 5 to 18 years. Our reference data will help clinicians and researchers assess and interpret the BMD of the proximal femur for Southeast Asian children.

Sex Differences in Bone Health Among Indian Older Adults with Obesity, Sarcopenia, and Sarcopenic Obesity

Age-related changes in fat and lean mass contribute to bone health, but these associations may be influenced by sex and ethnicity. This study investigated sex-specific associations of obesity and sarcopenia with bone mineral density (BMD) and bone mineral apparent density (BMAD) among Indian older adults. 1057 adults aged ≥ 50 years were included. Dual-energy X-ray absorptiometry (DXA) measured BMD at the hip, spine and whole-body, and BMAD was calculated as BMD/√bone area. Obesity was defined by body fat percentage (cut points; > 25% for men and > 35% for women), and sarcopenia was defined using the revised Asian Working Group for Sarcopenia classification with low hand grip strength (< 28 kg for men and < 18 kg for women) and appendicular lean mass index (< 7.0 kg/m² for men and < 5.4 kg/m² for women). Participants were classified into four groups: controls (no obesity or sarcopenia), obesity, sarcopenia, or sarcopenic obesity. Linear regression (β-coefficients and 95%CI) analyses were performed with adjustments for age, smoking status, protein intake, and socioeconomic status. Prevalence of sarcopenia (37%) and sarcopenic obesity (6%) were higher in men than women (17% and 4%, respectively). Compared with controls, men with obesity had lower whole-body BMD and BMAD, but women with obesity had higher hip and spine BMD and BMAD (all p < 0.05). Men, but not women, with sarcopenic obesity, had lower hip and whole-body BMD and BMAD (all p < 0.05) than controls. Men with sarcopenia had lower BMD and BMAD at the hip only, whereas women had lower BMD at all three sites and had lower BMAD at the hip and spine (all p < 0.05), compared with controls. Obesity, sarcopenia, and sarcopenic obesity have sex-specific associations with BMD and BMAD in Indian older adults. With the aging population in India, it is important to understand how body composition contributes to poor bone health among older adults.

Bone Mineral Density and Current Bone Health Screening Practices in Friedreich's Ataxia

Introduction

Friedreich's Ataxia (FRDA) is a progressive neurological disorder caused by mutations in both alleles of the frataxin (FXN) gene. Impaired bone health is a complication of other disorders affecting mobility, but there is little information regarding bone health in FRDA.

Methods

Dual energy X-ray absorptiometry (DXA) scan-based assessments of areal bone mineral density (aBMD) in individuals with FRDA were abstracted from four studies at the Children's Hospital of Philadelphia (CHOP). Disease outcomes, including the modified FRDA Rating Scale (mFARS), were abstracted from the FRDA Clinical Outcomes Measures Study (FACOMS), a longitudinal natural history study. A survey regarding bone health and fractures was sent to individuals in FACOMS-CHOP.

Results

Adults with FRDA (n = 24) have lower mean whole body (WB) (-0.45 vs. 0.33, p = 0.008) and femoral neck (FN) (-0.71 vs. 0.004, p = 0.02) aBMD Z-scores than healthy controls (n = 24). Children with FRDA (n = 10) have a lower WB-less-head (-2.2 vs. 0.19, p < 0.0001) and FN (-1.1 vs. 0.04, p = 0.01) aBMD than a reference population (n = 30). In adults, lower FN aBMD correlated with functional disease severity, as reflected by mFARS (R = -0.56, p = 0.04). Of 137 survey respondents (median age 27 y, 50% female), 70 (51%) reported using wheelchairs as their primary ambulatory device: of these, 20 (29%) reported a history of potentially pathologic fracture and 11 (16%) had undergone DXA scans.

Conclusions

Low aBMD is prevalent in FRDA, but few of even the highest risk individuals are undergoing screening. Our findings highlight potential missed opportunities for the screening and treatment of low aBMD in FRDA.

The Limited Impact of Low-Volume Recreational Dance on Three-Compartment Body Composition and Apparent Bone Mineral Density in Young Girls

Recreational dance is practiced worldwide as a multidimensional physical activity with a potential for prevention of a sedentary lifestyle and overweight/obesity. This study explored in young (7−15 year; n = 21) girls the effect of long-term (>1 year) exposure to recreational (2 h/w) dancing on three-compartment body composition. Recreational dancers (RD) were compared with recreational (≤4 h/w) artistic gymnasts (RG, n = 22) and physically active young girls not involved in structured extracurricular physical activity (control; C, n = 22), adjusting for confounding variables (age, body mass, menarche). We hypothesized for RD an intermediate body composition between RG and C. The three groups had similar age and body mass index. Body composition indices in RD were intermediate between that of C and RG, but RD values were not statistically significantly different vs. C. This agreed with the not statistically significant higher energy expenditure (MET-min/w) in RD vs. C (1357.7 ± 805.32 and 1090.9 ± 596.63, p = 0.172). In conclusion, long-term recreational dance exposure at low volume had limited positive effect on body composition of young girls vs. unstructured extracurricular physical activity. Future work will explore the potential of recreational dance at higher volume (3−4 h/w) to improve body composition in young girls.

Bone density in youth with prediabetes: results from the National Health and Nutrition Examination Survey, 2005-2006

Youth with type 2 diabetes might have suboptimal peak bone mass, but it is unknown whether similar effects are evident in youth with prediabetes. Results from this study suggest that diabetes-related effects on peak bone mass likely occur before disease onset, and involve the muscle-bone unit.

INTRODUCTION

Type 2 diabetes might adversely influence bone health around the age of peak bone mass, but it is unknown whether diabetes-related effects on areal bone mineral density (aBMD) are evident in youth with prediabetes. We compared age-related trends in aBMD and associations between lean body mass (LBM) and aBMD between children and adolescents with prediabetes vs. normal glucose regulation.

METHODS

Cross-sectional analysis of data from the National Health and Nutrition Examination Survey (2005-2006) in youth ages 12-20 years (49% female, 34% black) with prediabetes (n = 267) and normal glucose regulation (n = 1664). Whole body aBMD and LBM were assessed via DXA. LBM index (LBMI) and Z-scores for aBMD and LBMI were computed.

RESULTS

Unadjusted between-group comparisons revealed greater mean weight and LBMI Z-scores in youth with prediabetes vs. normal glucose regulation, but similar bone Z-scores between the two groups. While accounting for differences in BMI Z-score, there was a significant interaction between prediabetes status and age with respect to whole body aBMD Z-score (P < 0.05), such that children with prediabetes tended to have increased aBMD but adolescents and young adults with prediabetes tended have lower aBMD. Furthermore, the positive association between LBMI and whole body aBMD was moderated in youth with prediabetes (P < 0.001), who had slightly lower whole body aBMD for a given LBMI (P = 0.068). Lumbar spine bone measures did not differ between the two groups.

CONCLUSIONS

Type 2 diabetes-related threats to peak bone mass might occur prior to disease onset, therefore potentially impacting a considerable proportion of US youth.

Bone parameters of elite athletes with oligomenorrhea and prevalence seeking medical attention: a cross-sectional study

INTRODUCTION

Since the definition of secondary amenorrhea is cessation of regular menses for more than 3 months, it is likely that athletes with irregular menstrual cycles, including oligomenorrhea, do not consider the condition as serious. However, the consequences of untreated oligomenorrhea have not been investigated in elite track and field athletes.

MATERIALS AND METHODS

The cohort consisted of 91 elite-level track and field athletes. Body compositions, including bone parameters and bone turnover markers (BTMs), were measured.

RESULTS

Among the 91 participants, 52 were eumenorrheic and 33 were oligomenorrheic. The eumenorrheic athletes had significantly higher bone mineral density (BMD) and bone mineral content (BMC) of the lumbar spine, lower extremities, and whole body than had the oligomenorrheic athletes (p < 0.01). There were no significant differences in BTMs between the two groups, but oligomenorrheic athletes had significantly lower percent body fat.

CONCLUSION

More than 40% of the elite-level female track and field athletes in this study reported menstrual disorders with oligomenorrhea as the most common. However, none sought medical attention. As compared to the eumenorrheic athletes, the oligomenorrheic athletes had lower BMC and BMD. Hence, if an athlete is oligomenorrheic, bone parameter measurements are considerably important.

Associations of Maternal Serum Perfluoroalkyl Substances Concentrations with Early Adolescent Bone Mineral Content and Density: The Health Outcomes and Measures of the Environment (HOME) Study

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) may impair bone accrual and strength via endocrine disruption and nuclear receptor agonism, but human studies are primarily of adults or cross-sectional.

OBJECTIVES

We assessed associations of individual PFAS and their mixture during pregnancy with child bone mineral content (BMC) and areal bone mineral density (aBMD) at age 12 y.

METHODS

Among 206 mother-child pairs enrolled in a prospective cohort (2003-2006), we quantified perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorohexane sulfonic acid (PFHxS), and perfluorooctane sulfonic acid (PFOS) in maternal serum collected during gestation or delivery. When children were age 12 y, we performed dual energy X-ray absorptiometry and calculated BMC, aBMD, and bone mineral apparent density (BMAD) z -scores for six skeletal sites. We estimated covariate-adjusted z -score differences per doubling of individual PFAS using linear regression and assessed the PFAS mixture using quantile g-computation and Bayesian kernel machine regression. We explored whether associations were modified by child's sex or mediated by whole-body lean mass.

RESULTS

In covariate-adjusted models, we found that higher maternal serum concentrations of PFOA, PFNA, and the PFAS mixture were associated with lower total hip and forearm (one-third distal radius) BMC z -scores in children. Differences in forearm BMC z -scores were - 0.17 [95% confidence interval (CI): - 0.35 , 0.01] and - 0.24 (95% CI: - 0.44 , - 0.05 ) per doubling of PFOA and PFNA, respectively, and - 0.18 (95% CI: - 0.34 , - 0.02 ) per quartile increase in the PFAS mixture. Child's sex modified PFOA associations for some skeletal sites; for example, differences in spine BMAD z -score per doubling were - 0.31 (95% CI: - 0.58 , - 0.03 ) among males and 0.07 (95% CI: - 0.16 , 0.30) among females (modification p = 0.04 ). Except for PFNA among females, these associations were not mediated by whole-body lean mass.

DISCUSSION

Maternal PFAS concentrations during pregnancy may be associated with lower bone mineral accrual and strength in early adolescence. https://doi.org/10.1289/EHP9424.

Sarcopenia and preserved bone mineral density in paediatric survivors of high-risk neuroblastoma with growth failure

BACKGROUND

Survival from paediatric high-risk neuroblastoma (HR-NBL) has increased, but cis-retinoic acid (cis-RA), the cornerstone of HR-NBL therapy, can cause osteoporosis and premature physeal closure and is a potential threat to skeletal structure in HR-NBL survivors. Sarcopenia is associated with increased morbidity in survivors of paediatric malignancies. Low muscle mass may be associated with poor prognosis in HR-NBL patients but has not been studied in these survivors. The study objective was to assess bone density, body composition and muscle strength in HR-NBL survivors compared with controls.

METHODS

This prospective cross-sectional study assessed areal bone mineral density (aBMD) of the whole body, lumbar spine, total hip, femoral neck, distal 1/3 and ultradistal radius and body composition (muscle and fat mass) using dual-energy X-ray absorptiometry (DXA) and lower leg muscle strength using a dynamometer. Measures expressed as sex-specific standard deviation scores (Z-scores) included aBMD (adjusted for height Z-score), bone mineral apparent density (BMAD), leg lean mass (adjusted for leg length), whole-body fat mass index (FMI) and ankle dorsiflexion peak torque adjusted for leg length (strength-Z). Muscle-specific force was assessed as strength relative to leg lean mass. Outcomes were compared between HR-NBL survivors and controls using Student's t-test or Mann-Whitney U test. Linear regression models examined correlations between DXA and dynamometer outcomes.

RESULTS

We enrolled 20 survivors of HR-NBL treated with cis-RA [13 male; mean age: 12.4 ± 1.6 years; median (range) age at therapy initiation: 2.6 (0.3-9.1) years] and 20 age-, sex- and race-matched controls. Height-Z was significantly lower in HR-NBL survivors compared with controls (-1.73 ± 1.38 vs. 0.34 ± 1.12, P < 0.001). Areal BMD-Z, BMAD-Z, FMI-Z, visceral adipose tissue and subcutaneous adipose tissue were not significantly different in HR-NBL survivors compared with controls. Compared with controls, HR-NBL survivors had lower leg lean mass-Z (-1.46 ± 1.35 vs. - 0.17 ± 0.84, P < 0.001) and strength-Z (-1.13 ± 0.86 vs. - 0.15 ± 0.71, P < 0.001). Muscle-specific force was lower in HR-NBL survivors compared with controls (P < 0.05).

CONCLUSIONS

Bone mineral density and adiposity are not severely impacted in HR-NBL survivors with growth failure, but significant sarcopenia persists years after treatment. Future studies are needed to determine if sarcopenia improves with muscle-specific interventions in this population of cancer survivors.

Bone geometry and microarchitecture deficits in children with Alagille syndrome

Alagille syndrome (ALGS) is an autosomal dominant disorder attributed to mutations in the Notch signaling pathway. Children with ALGS are at increased risk for fragility fracture of unknown etiology. Our objective was to characterize bone mass, geometry, and microarchitecture in children with ALGS. This was a cross-sectional study of 10 children (9 females), ages 8-18 years, with a clinical diagnosis of ALGS. Bone density was assessed via DXA (Hologic Discovery A) at several skeletal regions. Tibia trabecular and cortical bone was assessed via pQCT (Stratec XCT 2000) at the distal 3% and 38% sites, respectively. Tibia bone microarchitecture was assessed via HR-pQCT (Scanco XtremeCT II) at an ultradistal site located at 4% of tibia length and a cortical site at 30% of tibia length. Z-scores were calculated for DXA and pQCT measures. In the absence of XtremeCT II HR-pQCT reference data, these outcome measures were descriptively compared to a sample of healthy children ages 5-20 years (n = 247). Anthropometrics and labs were also collected. Based on one-sample t-tests, mean Z-scores for height and weight (both p < .05), were significantly less than zero. DXA bone Z-scores were not significantly different from zero, but were highly variable. For pQCT bone measures, Z-scores for total bone mineral content at the distal 3% site and cortical bone mineral content, cortical area, and cortical thickness at the distal 38% site were significantly less than zero (all p < .05). There was good correspondence between pQCT measures of cortical thickness Z-scores and DXA Z-scores for aBMD at the whole body less head, 1/3 radius, and femoral neck (all p < .05). Compared to healthy children, those with ALGS generally had lower trabecular number and greater trabecular separation despite having greater trabecular thickness (measured via HR-pQCT). Bilirubin and bile acids, markers of hepatic cholestasis, were associated with poorer bone measures. For example, greater bilirubin was associated with lower trabecular number (Spearman's rho [ρ] = -0.82, p = .023) and greater trabecular separation (ρ = 0.82, p = .023) measured via HR-pQCT, and greater bile acids were associated with lower cortical area measured via pQCT (ρ = -0.78, p = .041) and lower serum insulin-like growth factor-1 (ρ = -0.86, p = .002). In summary, deficits in cortical bone size and trabecular bone microarchitecture were evident in children with ALGS. Further investigation is needed to understand the factors contributing to these skeletal inadequacies, and the manner in which these deficits contribute to increased fracture risk.

Safety and efficacy of teriparatide treatment for severe osteoporosis in patients with Duchenne muscular dystrophy

Osteoporosis is a major concern in patients with Duchenne muscular dystrophy. In this novel study of teriparatide treatment in 6 patients with severe osteoporosis, bone health (fractures, vertebral morphometry, and DXA) remained stable, with no adverse events. These findings will help inform future osteoporosis research in this challenging population.

INTRODUCTION

Despite standard therapy with vitamin D and bisphosphonates (BP), many patients with Duchenne muscular dystrophy (DMD) continue to sustain fragility fractures due to long-term glucocorticoid treatment and limited mobility. We aimed to evaluate the safety and efficacy of teriparatide for the treatment of severe osteoporosis in adolescent and young adult patients with DMD.

METHODS

We prospectively treated 6 patients with DMD who had severe osteoporosis with teriparatide 20 mcg subcutaneously daily for 1-2 years. Inclusion criteria were long-term glucocorticoid therapy, and severe osteoporosis despite treatment with BP, or intolerance to BP. We examined long bone and vertebral fracture outcomes, including vertebral morphometry measures, bone mineral density and content, bone formation markers, safety indices, and adverse events.

RESULTS

The mean age at teriparatide start was 17.9 years (range 13.9-22.1 years). All 6 patients were on daily glucocorticoids (mean ± SD; duration 10.9 ± 2.5 years) and 5 were non-ambulatory. Five patients had been treated with BP for 7.9 ± 4.2 years. All had vertebral and a history of long bone fragility fractures at baseline. Vertebral heights and Genant fracture grading remained stable. Long bone fracture rate appeared to decrease (from 0.84/year to 0.09/year); one patient sustained a long bone fracture at 6 months of treatment. Trajectories for change in bone mineral density and content were not different post- vs. pre-teriparatide. Procollagen type 1 amino-terminal propeptide (P1NP) increased, while laboratory safety indices remained stable and non-concerning. No adverse events were observed.

CONCLUSION

In six patients with DMD treated with teriparatide for severe osteoporosis, we observed stable bone health and modest increases in P1NP, without safety concerns. Further studies are needed to better understand teriparatide efficacy for treatment of osteoporosis in patients with DMD.

Management of primary and secondary osteoporosis in children

Osteoporosis in children differs from adults in terms of definition, diagnosis, monitoring and treatment options. Primary osteoporosis comprises primarily of osteogenesis imperfecta (OI), but there are significant other causes of bone fragility in children that require treatment. Secondary osteoporosis can be a result of muscle disuse, iatrogenic causes, such as steroids, chronic inflammation, delayed or arrested puberty and thalassaemia major. Investigations involve bone biochemistry, dual-energy X-ray absorptiometry scan for bone densitometry and vertebral fracture assessment, radiographic assessment of the spine and, in some cases, quantitative computed tomography (QCT) or peripheral QCT. It is important that bone mineral density (BMD) results are adjusted based on age, gender and height, in order to reflect size corrections in children. Genetics are being used increasingly for the diagnosis and classification of various cases of primary osteoporosis. Bone turnover markers are used less frequently in children, but can be helpful in monitoring treatment and transiliac bone biopsy can assist in the diagnosis of atypical cases of osteoporosis. The management of children with osteoporosis requires a multidisciplinary team of health professionals with expertise in paediatric bone disease. The prevention and treatment of fragility fractures and improvement of the quality of life of patients are important aims of a specialised service. The drugs used most commonly in children are bisphosphonates, that, with timely treatment, can give good results in improving BMD and reshaping vertebral fractures. The data regarding their effect on reducing long bone fractures are equivocal. Denosumab is being used increasingly for various conditions with mixed results. There are more drugs trialled in adults, but these are not yet licenced for children. Increasing awareness of risk factors for paediatric osteoporosis, screening and referral to a specialist team for appropriate management can lead to early detection and treatment of asymptomatic fractures and prevention of further bone damage.

Pediatric Reference Ranges for Ultradistal Radius Bone Density: Results from the Bone Mineral Density in Childhood Study

CONTEXT

The ultradistal (UD) radius is rich in trabecular bone and is easily measured by dual energy X-ray absorptiometry (DXA). UD radius areal bone mineral density (aBMD) may help identify trabecular bone deficits, but reference data are needed for research and clinical interpretation of this measure.

OBJECTIVE

We developed age-, sex-, and population ancestry-specific reference ranges for UD radius aBMD assessed by DXA and calculated Z-scores. We examined tracking of UD radius aBMD Z-scores over 6 years and determined associations between UD radius aBMD Z-scores and other bone measures by DXA and peripheral quantitative computed tomography.

DESIGN

Multicenter longitudinal study.

PARTICIPANTS

A total of 2014 (922 males, 22% African American) children ages 5 to 19 years at enrollment who participated in the Bone Mineral Density in Childhood Study.

MAIN OUTCOME MEASURE

UD radius aBMD.

RESULTS

UD radius aBMD increased nonlinearly with age (P < 0.001) and tended to be greater in males versus females (P = 0.054). Age-, sex-, and ancestry-specific UD radius aBMD reference curves were constructed. UD radius aBMD Z-scores positively associated with Z-scores at other skeletal sites (r = 0.54-0.64, all P < 0.001) and peripheral quantitative computed tomography measures of distal radius total volumetric BMD (r = 0.68, P < 0.001) and trabecular volumetric BMD (r = 0.70, P < 0.001), and was weakly associated with height Z-score (r = 0.09, P = 0.015). UD radius aBMD Z-scores tracked strongly over 6 years, regardless of pubertal stage (r = 0.66-0.69; all P < 0.05).

CONCLUSION

UD radius aBMD Z-scores strongly associated with distal radius trabecular bone density, with marginal confounding by stature. These reference data may provide a valuable resource for bone health assessment in children.

A Contemporary View of the Definition and Diagnosis of Osteoporosis in Children and Adolescents

The last 2 decades have seen growing recognition of the need to appropriately identify and treat children with osteoporotic fractures. This focus stems from important advances in our understanding of the genetic basis of bone fragility, the natural history and predictors of fractures in chronic conditions, the use of bone-active medications in children, and the inclusion of bone health screening into clinical guidelines for high-risk populations. Given the historic focus on bone densitometry in this setting, the International Society for Clinical Densitometry published revised criteria in 2013 to define osteoporosis in the young, oriented towards prevention of overdiagnosis given the high frequency of extremity fractures during the growing years. This definition has been successful in avoiding an inappropriate diagnosis of osteoporosis in healthy children who sustain long bone fractures during play. However, its emphasis on the number of long bone fractures plus a concomitant bone mineral density (BMD) threshold ≤ -2.0, without consideration for long bone fracture characteristics (eg, skeletal site, radiographic features) or the clinical context (eg, known fracture risk in serious illnesses or physical-radiographic stigmata of osteoporosis), inappropriately misses clinically relevant bone fragility in some children. In this perspective, we propose a new approach to the definition and diagnosis of osteoporosis in children, one that balances the role of BMD in the pediatric fracture assessment with other important clinical features, including fracture characteristics, the clinical context and, where appropriate, the need to define the underlying genetic etiology as far as possible.

Does Bone Mineral Apparent Density Facilitate Accurate Identification of Osteoporosis in the Short Postmenopausal Women?

OBJECTIVE

Height is one of the most important aspects affecting the areal bone mineral density (BMD). There are several height adjustments in children but none in widespread use for adults. This is specifically a problem in ethnic groups where mean height is substantially lower. We hypothesized that height adjustment of areal BMD would reduce the misclassification in short individuals.

MATERIALS AND METHODS

This is a retrospective study involving 373 postmenopausal women. Their records were reviewed and bone mineral apparent density (BMAD) were calculated. Areal BMD T-scores and BMAD T-scores were then compared.

RESULTS

The mean height of the cohort was 154.4 cm. There were 47 women who were defined as short (≤147 cm). In short women, BMAD neither showed improvement nor decrement in T-scores, and BMAD T-scores predicted more number of osteoporosis than BMD T-scores. When divided into height ranges, taller women (>160 cm) showed worsening of BMAD T-scores as compared to BMD T-scores (Chi-square test for trend P < 0.001). Hence, BMAD might actually "correct" for larger bone and not shorter bones.

CONCLUSION

BMAD was not found to be a suitable alternative in short postmenopausal women to accurately determine whether the low bone density in them is because of dual-energy X-ray absorptiometry artifact or whether they truly have a low density.

Celiac Disease and Bone Health in Children and Adolescents: A Systematic Review and Meta-Analysis

CONTEXT

Celiac disease is characterized by deficits in bone mineral accrual and longitudinal growth.

OBJECTIVE

The purpose of this study was to determine the differences in bone health and stature among children and adolescents with celiac disease versus healthy controls.

DATA SOURCES

Articles published before February 27, 2018 were located using searches of the Physical Education Index (n = 186), PubMed (n = 180), Scopus (n = 3), SPORTDiscus (n = 3), and Web of Science (n = 4).

STUDY SELECTION

Bone mineral content (BMC) and areal bone mineral density (aBMD) were assessed via dual-energy X-ray absorptiometry, and height was measured using a stadiometer.

DATA EXTRACTION

Effect sizes (ES) were calculated as follows: the mean difference of the celiac disease group and healthy control group, divided by the pooled standard deviation. The inverse variance weight was used to calculate the overall mean ES. Random-effects models were used to aggregate a mean ES, 95% confidence intervals (CIs) and to identify potential moderators.

RESULTS

The results of 30 effects gathered from 12 studies published between 1996 and 2017 indicated BMC (ES = -0.54, 95% CI: -0.69 to -0.40; p < 0.0001) and aBMD (ES = 0.72, 95% CI: -0.96 to -0.47; p < 0.0001) were lower in youth with celiac disease.

LIMITATIONS

These results were limited to only cross-sectional and baseline data from longitudinal studies reporting BMC and BMD, however did not assess changes in bone health over time.

CONCLUSION

Children and adolescents with celiac disease have suboptimal bone health and shorter stature.

Adults with pathogenic MC4R mutations have increased final height and thereby increased bone mass

Pathogenic mutations in the melanocortin-4 receptor (MC4R) are associated with obesity, increased linear growth, and higher bone mass in children, and rodent studies have indicated an effect of the MC4R on bone turnover. Furthermore, GLP-1 receptor agonists (GLP-1 RAs) may influence bone metabolism. However, these associations have not been assessed in adults with pathogenic MC4R mutations. Thus, we wished to assess the impact of the MC4R on bone mass and metabolism. Secondly, we wished to investigate the impact of the GLP-1 RA liraglutide on bone mass in adults with pathogenic MC4R mutations. 17 patients with obesity-causing MC4R mutations (BMI: 35.5 ± 7.6) and 35 matched control participants with common obesity (BMI: 34.3 ± 7.1) underwent a DEXA scan for assessment of bone mineral density (BMD), bone mineral apparent density [BMAD = (BMD/√(bone area)], and bone turnover markers (BTMs). Individuals with a BMI above 28 (14 MC4R mutation carriers and 28 matched control participants) underwent 16 weeks treatment with liraglutide 3.0 mg. The MC4R group had higher BMD [mean difference: 0.065 g/m² (- 0.008 to 0.138), p = 0.03], but BMAD and BTMS were not different compared to the control group. In response to liraglutide, BMAD increased in the control group, compared to no change in the MC4R group [mean group difference: 0.0007 (0.0001-0.001), p = 0.04]. In conclusion, BMD is increased in MC4R causal obesity compared to common obesity, but when corrected for body size (BMAD), bone mass was not increased, and no evidence of an influence of the MC4R on bone metabolism in adults was found. Liraglutide treatment did not change bone metabolism in MC4R causal obesity, but increased bone mass as measured by BMAD in common obesity.

The role of delayed bone age in the evaluation of stature and bone health in glucocorticoid treated patients with Duchenne muscular dystrophy

Background

Low bone mineral density and an increased risk of appendicular and vertebral fractures are well-established consequences of Duchenne muscular dystrophy (DMD) and the risk of fractures is exacerbated by long-term glucocorticoid treatment. Monitoring of endocrine and skeletal health and timely intervention in at-risk patients is important in the management of children with DMD.

Methods

As part of the Norwegian Duchenne muscular dystrophy cohort study, we examined the skeletal maturation of 62 boys less than 18 years old, both currently glucocorticoid treated (n = 44), previously treated (n = 6) and naïve (n = 12). The relationship between bone age, height and bone mineral density (BMD) Z-scores was explored.

Results

The participants in the glucocorticoid treated group were short in stature and puberty was delayed. Bone age was significantly delayed, and the delay increased with age and duration of treatment. The difference in height between glucocorticoid treated and naïve boys was no longer significant when height was corrected for delayed skeletal maturation. Mean BMD Z-scores fell below − 2 before 12 years of age in the glucocorticoid treated group, with scores significantly correlated with age, duration of treatment and pubertal development. When BMD Z-scores were corrected for by retarded bone age, the increase in BMD Z-scores was significant for all age groups.

Conclusion

Our results suggest that skeletal maturation should be assessed in the evaluation of short stature and bone health in GC treated boys with DMD, as failing to consider delayed bone age leads to underestimation of BMD Z-scores and potentially overestimation of fracture risk.

The Utility of DXA Assessment at the Forearm, Proximal Femur, and Lateral Distal Femur, and Vertebral Fracture Assessment in the Pediatric Population: 2019 ISCD Official Position

Dual-energy X-ray absorptiometry (DXA) is widely used in the evaluation of bone fragility in children. Previous recommendations emphasized total body less head and lumbar spine DXA scans for clinical bone health assessment. However, these scan sites may not be possible or optimal for all groups of children with conditions that threaten bone health. The utility of DXA scans of the proximal femur, forearm, and radius were evaluated for adequacy of reference data, precision, ability of predict fracture, and applicability to all, or select groups of children. In addition, the strengths and limitations of vertebral fracture assessment by DXA were evaluated. The new Pediatric Positions provide guidelines on the use of these additional measures in the assessment of skeletal health in children.

Dual-energy X-ray absorptiometry pitfalls in Thalassemia Major

BACKGROUND

Low mineral mass and reduced bone strength with increased fracture risk are the main causes of morbidity in Thalassemia Major (TM). The pathogenesis is multifactorial and includes ineffective erythropoiesis with medullary expansion, multiple endocrine dysfunctions, direct iron bone deposition, deferoxamine-induced bone dysplasia, and reduced physical activity associated with disease complications. Dual-energy X-ray absorptiometry (DXA) is the "gold standard" for bone mineral density (BMD) assessment and for bone strength and quality evaluation. This method identifies patients at greater risk of fragility fractures, guiding treatment and monitoring response to therapy. In TM, DXA shows limitations concerning BMD calculation accuracy and fracture risk prediction. One of the main challenges in the assessment of bone health in patients with TM is the accurate interpretation of densitometric results.

PURPOSE

This review investigates the major pitfalls in DXA implementation and interpretation in TM.

METHODS

Available literature has been assessed.

CONCLUSIONS

DXA shows limitations in assessing bone mineral "status" in TM, especially in the paediatric population, due to the peculiar characteristics of bone architecture and deformities associated with the disease. A radiological technique adjustment in this population is mandatory.

Lumbar Spine Bone Mineral Apparent Density in Children: Results From the Bone Mineral Density in Childhood Study

CONTEXT

Dual-energy X-ray absorptiometry (DXA) is a cornerstone of pediatric bone health assessment, yet differences in height-for-age confound the interpretation of areal bone mineral density (aBMD) measures. To reduce the confounding of short stature on spine bone density, use of bone mineral apparent density (BMAD) and height-for-age Z-score (HAZ)‒adjusted aBMD (aBMDHAZ) are recommended. However, spine BMAD reference data are sparse, and the degree to which BMAD and aBMDHAZ account for height-related artifacts in bone density remains unclear.

OBJECTIVE

We developed age-, sex-, and population ancestry‒specific spine BMAD reference ranges; compared height-adjustment methods in accounting for shorter stature; and assessed the stability of these measures over time.

DESIGN

Secondary analysis of data from a previous longitudinal study.

PARTICIPANTS

Children and adolescents aged 5 to 19 years at baseline (n = 2014; 922 males; 22% black) from the Bone Mineral Density in Childhood Study.

MAIN OUTCOME MEASURES

Lumbar spine BMAD and aBMDHAZ from DXA.

RESULTS

Spine BMAD increased nonlinearly with age and was greater in blacks and females (all P < 0.001). Age-specific spine BMAD z-score reference curves were constructed for black and non‒black males and females. Overall, both BMAD and aBMDHAZz scores reduced the confounding influence of shorter stature, but neither was consistently unbiased across all age ranges. Both BMAD and aBMDHAZz scores tracked strongly over 6 years (r = 0.70 to 0.80; all P < 0.001).

CONCLUSION

This study provided robust spine BMAD reference ranges and demonstrated that BMAD and aBMDHAZ partially reduced the confounding influence of shorter stature on bone density.