Dual-energy X-ray absorptiometry interpretation and reporting in children and adolescents: the revised 2013 ISCD Pediatric Official Positions

Agreement Between Dual-Energy X-Ray Absorptiometry and Quantitative Ultrasound to Evaluate Bone Health in Adolescents: The PRO-BONE Study

PURPOSE

The present study aims to investigate the association between dual-energy X-ray absorptiometry (DXA) and quantitative ultrasound (QUS) parameters and the intermethods agreement in active males.

METHODS

In this cross-sectional study, bone health (by DXA and calcaneal QUS), physical activity (by accelerometers), and anthropometrics measurements were assessed in 117 active adolescents (12-14 y old). Bivariate correlation coefficients were calculated to assess the relationships between DXA standard regions of interest and QUS parameters. Intraclass correlation coefficients and Bland-Altman plots were used to assess the level of agreement between bone mineral content regions derived from DXA and stiffness index. The measurements were z score transformed for comparison.

RESULTS

Most QUS parameters were positive and significantly correlated with DXA outcomes (stiffness index: r = .43-.52; broadband ultrasound attenuation: r = .50-.58; speed of sound: r = .25-.27) with the hip showing the highest correlations. Moreover, the present study found fair to good intraclass correlation coefficients of agreement (.60-.68) between DXA and QUS to assess bone health. The Bland-Altman analysis showed a limited percentage of outliers (3.2%-8.6%).

CONCLUSION

QUS device could represent an acceptable alternative method to assess bone health in active adolescent males.

Serum 25-hydroxyvitamin D and bone mineral density among children and adolescents in a Northwest Chinese city

Although vitamin D is essential for bone health, little is known about prevalence of vitamin D deficiency and low bone mineral density (BMD) among children, especially those in developing countries. It also remains unclear whether serum 25-hydroxyvitamin D [25(OH)D] is associated with BMD among children. We investigated these questions among children and adolescents in Yinchuan (latitude: 38° N), Ningxia, an economically underdeveloped province in Northwest China. A total of 1582 children (756 boys and 826 girls), aged 6-18 years, were recruited from schools using the stratified random sampling method in fall 2015. Serum 25(OH)D concentrations were measured by enzyme-linked immunosorbent assay, and BMD was quantified by dual-energy X-ray absorptiometry. Vitamin D deficiency (defined as serum 25(OH)D ≤ 37.5 nmol/L) was present in 35.5% of study subjects. There were no clear patterns of differences in serum 25(OH)D concentrations across the four age groups compared (6-9 years, 10-13 years, 14-16 years, and 17-18 years). The prevalence of low total body less head (TBLH) BMD (defined as a Z-score of ≤ -2.0 standard deviations away from the mean BMD values of the Chinese pediatric reference population) among children examined was 1.8% and was not significantly different among the four age groups considered. Linear regression analysis revealed that age, weight, and height were significantly and positively associated with TBLH BMD and that the strongest determinant of TBLH BMD was age in boys and weight in girls. There were no significant correlations between serum 25(OH)D concentrations and BMD obtained for total body and at various skeletal sites (r ranged from -0.005 to 0.014) regardless of whether children evaluated were sufficient, insufficient, or deficient in vitamin D. In conclusion, more than one-third of children and adolescents in a Northwest Chinese city were deficient in vitamin D but only <2% of them developed low BMD.

Growth, bone health & ambulatory status of boys with DMD treated with daily vs. intermittent oral glucocorticoid regimen

Oral glucocorticoids (GC) preserve muscle strength and prolong walking in boys with Duchenne muscular dystrophy (DMD). Although vertebral fractures have been reported in boys taking GC, fracture rates for different GC regimes have not been investigated. The aim of this pragmatic longitudinal study was to compare growth, body mass, bone mineral density (BMD), vertebral fractures (VF) and ambulatory status in boys with DMD on daily (DAILY) or intermittent (INTERMITTENT), oral GC regimens. A convenience sample of 50 DMD boys from two centres was included in the study; 25 boys each were on the DAILY or INTERMITTENT regimen. Size adjusted lumbar spine BMD (LS BMAD), total body less head BMD (TBLH), by DXA and distal forearm bone densities by pQCT, GC exposure, VF assessment and ambulatory status were analysed at three time points; baseline, 1 and 2 years. At baseline, there were no differences in age, GC duration or any bone parameters. However, DAILY boys were shorter (height SDS DAILY = -1.4(0.9); INTERMITTENT = -0.8(1.0), p = 0.04) with higher BMI (BMI SDS DAILY = 1.5(0.9); INTERMITTENT = 0.8(1.0), p = 0.01). Over 2 years, DAILY boys got progressively shorter (delta height SDS DAILY = -0.9(1.1); INTERMITTENT = +0.1(0.6), p < 0.001). At their 2 year assessment, 5 DAILY and 10 INTERMITTENT boys were non-ambulant. DAILY boys had more VFs than INTERMITTENT boys (10 versus 2; χ² p = 0.008). BMAD SDS remained unchanged between groups. TBLH and radius BMD declined significantly but the rate of loss was not different. In conclusion, there was a trend for more boys on daily GCs to remain ambulant but at the cost of more VFs, greater adiposity and markedly diminished growth. In contrast, boys on intermittent GCs had fewer vertebral fractures but there was a trend for more boys to loose independent ambulation.

Treating exercise-associated low testosterone and its related symptoms

The Exercise-Hypogonadal Male Condition (EHMC) has been described to occur in athletes who experience low serum testosterone and associated symptoms. While high volumes of endurance exercise can lead to reduced testosterone concentrations in men, similar changes may occur in other sports including anerobic and power sports such as American football, and weight class sports such as wrestling. A reduced testosterone concentration alone does not necessarily warrant treatment, but when it is accompanied by symptoms of hypogonadism, such as fatigue, sexual dysfunction, and/or low bone mineral density (BMD), an athlete's performance and/or health may suffer. While pharmacological treatments such as testosterone or clomiphene citrate have been shown to be effective in treating hypogonadism, these options are not available to athletes competing in sports governed by the World Anti-Doping Agency. We recommend treatment of EHMC in athletes should include nutritional intervention and modification of training. Recognizing EHMC's existence in male athletes is important to optimize their health.

Bone Mineral Density Corrected for Size in Childhood Leukaemia Survivors Treated with Haematopoietic Stem Cell Transplantation and Total Body Irradiation

BACKGROUND

Childhood leukaemia survivors treated with haematopoietic stem cell transplantation and total body irradiation (HSCT-TBI) have multiple risk factors for reduced bone mineral density (BMD) and growth failure; hence, BMD assessment must take body size into consideration. This study aimed to evaluate size-corrected BMD in leukaemia survivors treated with and without HSCT-TBI.

METHODS

Childhood leukaemia survivors treated with HSCT-TBI (n = 35), aged 17.3 (10.5-20.9) years, were compared with those treated with chemotherapy only, (n = 16) aged 18.5 (16.1-20.9) years, and population references. Outcome measures included anthropometric measurements and BMD by dual-energy X-ray absorptiometry. BMD was corrected for size as bone mineral apparent density (BMAD). Statistical analysis was performed by 1- and 2-sample t tests as well as regression analysis (5% significance).

RESULTS

HSCT-TBI survivors were lighter and shorter with reduced spinal heights compared with chemotherapy-only subjects and population references. Compared with population references, HSCT-TBI survivors showed lower BMD standard deviation scores (SDS) (p = 0.008), but no difference in BMAD-SDS, and chemotherapy-only survivors showed no differences in neither BMD-SDS nor BMAD-SDS. All HSCT-TBI participants with BMD-SDS <-2 had BMAD-SDS >-2. BMAD-SDS was negatively associated with age (r = -0.38, p = 0.029) in HSCT-TBI survivors.

CONCLUSIONS

Size-corrected BMD are normal in HSCT-TBI survivors in young adulthood, but may reduce overtime. BMD measurements should be corrected for size in these patients to be clinically meaningful.

Continuous Subcutaneous Recombinant Parathyroid Hormone (1-34) Infusion in the Management of Childhood Hypoparathyroidism Associated with Malabsorption

BACKGROUND/AIMS

Hypoparathyroidism associated with malabsorption can be particularly challenging to manage due to limited and erratic intestinal absorption of calcium and vitamin D analogues, resulting in episodes of hypo- or hypercalcaemia. We evaluated the role of continuous subcutaneous recombinant parathyroid hormone (rhPTH 1-34) infusion (CSPI) in children with hypoparathyroidism associated with intestinal malabsorption resistant to conventional therapy.

METHOD

Four patients (8-13 years of age), with symptomatic hypocalcaemia resistant to conventional therapy, were started on CSPI (follow-up 3-8 years) in two paediatric endocrinology units in Europe.

RESULTS

Serum calcium normalized within 48 h of commencing treatment in all 4 patients. An average rhPTH 1-34 dose of 0.4 µg/kg/day resulted in a substantial reduction in symptomatic hypocalcaemia and hypo-/hypercalcaemia-related hospital admissions. An increased alkaline phosphatase activity was noted in the first 6 months on CSPI, indicating an increase in bone turnover. In 2 patients with elevated urinary calcium excretion before CSPI, this normalized in the first year on treatment. No significant side effects were noticed in the short or long term, with patient-reported preference of CSPI over conventional treatment.

CONCLUSION

CSPI is a promising and effective treatment option for managing hypocalcaemia and hyperphosphataemia in children with hypoparathyroidism associated with intestinal malabsorption.

Bone Health and Osteoporosis Management of the Patient With Duchenne Muscular Dystrophy

Duchenne muscular dystrophy is associated with an increased risk of bone fragility due to the adverse effects of prolonged glucocorticoid therapy and progressive muscle weakness on bone strength. Osteoporosis manifests clinically as low-trauma long-bone and vertebral fractures (VFs), with VFs frequent, particularly in those treated with glucocorticoid therapy. It is increasingly recognized that bone pain, medical complications of osteoporosis (such as fat embolism syndrome), and the potential for permanent, fracture-induced loss of ambulation can be mitigated with timely bone health surveillance and management. This includes periodic spine radiographs for VF detection because VFs can be asymptomatic in their early phases and thereby go undetected in the absence of monitoring. With this article, we provide a comprehensive review of the following 4 phases of bone health management: (1) bone health monitoring, which is used to identify early signs of compromised bone health; (2) osteoporosis stabilization, which is aimed to mitigate back pain and interrupt the fracture-refracture cycle through bone-targeted therapy; (3) bone health maintenance, which has the goal to preserve the clinical gains realized during the stabilization phase through ongoing bone-targeted therapy; and (4) osteoporosis therapy discontinuation, which places those who are eligible for discontinuation of osteoporosis treatment back on a health monitoring program. In the course of reviewing these 4 phases of management, we will discuss the criteria for diagnosing osteoporosis, along with detailed recommendations for osteoporosis intervention including specific drugs, dose, length of therapy, contraindications, and monitoring of treatment efficacy and safety.

Can radial bone mineral density predict spinal bone mineral density in patients with advanced Duchenne muscular dystrophy?

In advanced Duchenne muscular dystrophy (DMD), patients with high bone fracture risk due to osteoporosis, it is difficult to measure spinal bone mineral density (BMD) because of maintaining proper posture. This study began with the idea that if we diagnose and manage osteoporosis by predicting spinal BMD through easily testable radial BMD, we could prevent fracture and improve quality of life in DMD patients. In 61 DMD patients aged 20 years or older who were admitted to Gangnam Severance Hospital from April 2013 to May 2015, radial BMD and spinal BMD were measured to compare their Z-scores. In 45 patients, the z-score was less than -2.0 in spinal BMD defined as osteoporosis. And the optimal range of Z-score in the radius was -5.2 to -5.0 (sensitivity 78.9%, specificity 71.4%). Only through the radius BMD, spinal BMD can be predicted and we suggest appropriate times for treatments.

Investigation of the Relationship Between Fok1 and Col1A1 Gene Polymorphisms and Development of Treatment-Related Bone Complications in Children with Acute Lymphoblastic Leukemia

Objective:

In acute lymphoblastic leukemia (ALL), various clinical risk factors and genetic predispositions contribute to the development of bone complications during and after chemotherapy. In this study, we aimed to investigate whether vitamin D receptor (VDR) Fok1 and collagen protein Col1A1 Sp1-binding site gene polymorphisms, which are important in bone mineral and matrix formation, have effects on the development of bone abnormalities in childhood ALL survivors.

Materials and Methods:

Fifty children with ALL who were treated with the ALL Berlin-Frankfurt-Muenster-95 protocol between 1998 and 2008 and were followed for at least 7 years were enrolled. The control group consisted of 96 healthy children. VDR Fok1 and Col1A1 Sp1-binding site gene polymorphisms were analyzed by polymerase chain reaction and restriction fragment length polymorphism. Bone mineral density (BMD) and markers of bone metabolism were all noted. All patients who presented with pain in the joints were examined for bone pathologies while on chemotherapy or during long-term follow-up.

Results:

Low BMD (16%), osteoporosis (12%), and osteonecrosis (8%) were present in a total of 18 patients (36%). The frequency of osteonecrosis and total bone abnormalities was significantly higher in children aged ≥10 years (p=0.001). The risk of low BMD and osteonecrosis was higher in those with vitamin D deficiency. Only the Col1A1 Sp1-binding site gene polymorphism showed a significant association in ALL patients with osteonecrosis.

Conclusion:

The development of therapy-induced bone mineral loss and osteonecrosis in children with ALL is frequent and the risk is especially higher in children aged ≥10 years and with vitamin D deficiency. The association between Col1A1 Sp1-binding site gene polymorphisms and osteonecrosis has to be assessed in a larger group of ALL survivors.

rhIGF-1 Treatment Increases Bone Mineral Density and Trabecular Bone Structure in Children with PAPP-A2 Deficiency

AIM

Our objective was to determine changes in bone mineral density (BMD), trabecular bone score (TBS), and body composition after 2 years of therapy with recombinant human insulin-like growth factor-1 (rhIGF-1) in 2 prepubertal children with a complete lack of circulating PAPP-A2 due to a homozygous mutation in PAPP-A2 (p.D643fs25*) resulting in a premature stop codon.

METHODS

Body composition, BMD, and bone structure were determined by dual-energy X-ray absorptiometry at baseline and after 1 and 2 years of rhIGF-1 treatment.

RESULTS

Height increased from 132 to 145.5 cm (patient 1) and from 111.5 to 124.5 cm (patient 2). Bone mineral content increased from 933.40 to 1,057.97 and 1,152.77 g in patient 1, and from 696.12 to 773.26 and 911.51 g in patient 2, after 1 and 2 years, respectively. Whole-body BMD also increased after 2 years of rhIGF-1 from baseline 0.788 to 0.869 g/cm2 in patient 1 and from 0.763 to 0.829 g/cm2 in patient 2. After 2 years of treatment, both children had an improvement in TBS. During therapy, a slight increase in body fat mass was seen, with a concomitant increase in lean mass. No adverse effects were reported.

CONCLUSION

Two years of rhIGF-1 improved growth, with a tendency to improve bone mass and bone microstructure and to modulate body composition.

Skeletal Status, Body Composition, and Glycaemic Control in Adolescents with Type 1 Diabetes Mellitus

BACKGROUND

Disturbed bone turnover, osteoporosis, and increased fracture risk are late complications of insulin-dependent diabetes mellitus. Little is known about how far and to what extent can glycaemic control of type 1 diabetes mellitus (T1DM) prevent disturbances of bone health and body composition during the growth and maturation period.

OBJECTIVE

The aim of this cross-sectional study was to compare the skeletal status outcomes and body composition between patients stratified by glycaemic control (1-year HbA1c levels) into well- and poorly-controlled subgroups in a population of T1DM adolescents, that is, <8% and ≥8%, respectively.

SUBJECTS AND METHODS

Skeletal status and body composition were evaluated in 60 adolescents with T1DM (53.3% female; mean aged: 15.1 ± 1.9 years; disease duration: 5.1 ± 3.9 years) using dual energy X-ray absorptiometry (GE Prodigy). The results were compared to age- and sex-adjusted reference values for healthy controls. The calculated Z-scores of different metabolic control subgroups were compared. Clinical data was also assessed.

RESULTS

As evidenced by Z-scores, patients with T1DM revealed a significantly lower TBBMD (total body bone mineral density), TBBMC (total body bone mineral content), S24BMD (bone mineral density of lumbar spine L2-L4), and TBBMC/LBM ratio (total body bone mineral content/lean body mass), but higher FM (fat mass) and FM/LBM ratio (fat mass/lean body mass) values compared to an age- and sex-adjusted general population. The subset (43.3% patients) with poor metabolic control (HbA1c ≥ 8%) had lower TBBMD, TBBMC, and LBM compared to respective values noted in the HbA1c < 8% group, after adjusting for confounders (mean Z-scores: -0.74 vs. -0.10, p = 0.037; -0.67 vs. +0.01, p = 0.026; and -0.45 vs. +0.20, p = 0.043, respectively). Additionally, we found a significant difference in the TBBMC/LBM ratio (relative bone strength index) between the metabolic groups (-0.58 vs. -0.07; p = 0.021). A statistically significant negative correlation between 1-year HbA1c levels and Z-scores of TBBMD, TBBMC, and LBM was also observed. In patients with longer disease duration, a significant negative correlation was established only for TBBMD, after adjusting for confounders. The relationships between densitometric values and age at onset of T1DM and sex were not significant and showed no relation to any of the analysed parameters of the disease course.

CONCLUSION

Findings from this study of adolescents with T1DM indicate that the lower Z-scores of TBBMD, TBBMC, and LBM as well as the TBBMC/LBM ratio are associated with increased HbA1c levels. Their recognition can be crucial in directing strategies to optimise metabolic control and improve diabetes management for bone development and maintenance in adolescents with T1DM.

Response to Long-term Vitamin D Therapy for Bone Disease in Children With Sickle Cell Disease

Patients with sickle cell disease (SCD) are at risk for bone fragility from multiple factors including vitamin D deficiency. To date, no studies have evaluated the efficacy and safety of long-term vitamin D therapy for bone disease in children with SCD. We report a cohort of 4 children with SCD found to have severe vitamin D deficiency, secondary hyperparathyroidism, and abnormal bone mineral density treated with monthly high-dose oral cholecalciferol over 2 years. All patients exhibited a positive response to therapy without hypervitaminosis D or hypercalcemia. Further studies are needed to standardize guidelines for optimal vitamin D dosing and prevention of toxicity.

Update on bone density measurements and their interpretation in children and adolescents

Following the increased awareness about the central role of the pediatric age in building bone for life, clinicians face more than ever the necessity of assessing bone health in pediatric subjects at risk for early bone mass derangements or in healthy children, in order to optimize their bone mass accrual and prevent osteoporosis. Although the diagnosis of osteoporosis is not made solely upon bone mineral density measurements during growth, such determination can be very useful in the follow-up of pediatric patients with primary and secondary osteoporosis. The ideal instrument would give information on the mineral content and density of the bone, and on its architecture. It should be able to perform the measurements on the skeletal sites where fractures are more frequent, and it should be minimally invasive, accurate, precise and rapid. Unfortunately, none of the techniques currently utilized fulfills all requirements. In the present review, we focus on the pediatric use of dual-energy X-ray absorptiometry (DXA), quantitative computed tomography (QCT), peripheral QCT (pQCT), and magnetic resonance imaging (MRI), highlighting advantages and limits for their use and providing indications for bone densitometry interpretation and of vertebral fractures diagnosis in pediatric subjects.

Tracking of bone mass from childhood to puberty: a 7-year follow-up. The CHAMPS study DK

Bone mass in childhood is highly influenced by puberty. At the same age, bone mass was higher for pubertal than pre-pubertal children. A high level of tracking during 7 years from childhood through puberty was shown, indicating that early levels of bone mass may be important for later bone health.

INTRODUCTION

Bone mass development in childhood varies by sex and age, but also by pubertal stage. The objectives of this study were to (1) describe bone mass development in childhood as it relates to pubertal onset and to (2) determine the degree of tracking from childhood to adolescence.

METHODS

A longitudinal study with 7 years of follow-up was initiated in 2008 to include 831 children (407 boys) aged 8 to 17 years. Participants underwent whole body dual-energy X-ray absorptiometry (DXA) scanning, blood collection to quantify luteinizing hormone levels, and Tanner stage self-assessment three times during the 7-year follow-up. Total body less head bone mineral content, areal bone mineral density, and bone area were used to describe development in bone accrual and to examine tracking over 7 years.

RESULTS

Bone mass in pubertal children is higher than that of pre-pubertal children at the same age. Analysing tracking with quintiles of bone mass Z-scores in 2008 and 2015 showed that more than 80% of participants remained in the same or neighbouring quintile over the study period. Tracking was confirmed by correlation coefficients between Z-scores at baseline and 7-year follow-up (range, 0.80-0.84).

CONCLUSIONS

Bone mass is highly influenced by pubertal onset, and pubertal stage should be considered when examining children's bone health. Because bone mass indices track from childhood into puberty, children with low bone mass may be at risk of developing osteoporosis later in life.

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

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

Endocrine Late Effects in Childhood Cancer Survivors

Endocrine complications are highly prevalent in childhood cancer survivors. Approximately 50% of survivors will experience at least one hormonal disorder over the course of their lives. Endocrine complications often are observed in survivors previously treated with radiation to the head, neck, or pelvis. We provide an overview the most common endocrine late effects seen in survivors, including hypothalamic-pituitary dysfunction, primary thyroid dysfunction, obesity, diabetes mellitus, metabolic syndrome, and decreased bone mineral density. Primary gonadal injury is discussed elsewhere in this series. Given a variable latency interval, a systematic approach where individuals are periodically screened on the basis of their risk factors can help to improve health outcomes by prompt diagnosis and treatment of evolving endocrinopathies. These recommendations must be revised in the future given changes and improvements in cancer treatment over time.

Pediatric dual-energy X-ray absorptiometry in clinical practice: What the clinicians need to know

The importance of childhood and adolescence for bone development and mineral accrual is increasingly accepted, leading to a need of suitable methods for monitoring bone health even in pediatric setting. Among the several different imaging methods available for clinical measurement of bone mineral density (BMD) in children, dual-energy X-ray absorptiometry (DXA) is the most widely available and commonly used due to its reproducibility, negligible radiation dose and reliable pediatric reference data. Nevertheless, DXA in children has some technical specific features that should be known by those physicians who interpret and report this examination. We provide recommendations for optimal DXA scan reporting in pediatric setting, including indications, skeletal sites to be examined, parameters to be measured, timing of follow-up BMD measurements. Adequate report and analysis of DXA examinations are essential to prevent over- and underdiagnosis of bone mineral impairment in pediatric patients. In conclusion, a complete and exhaustive DXA report in children and adolescents is mandatory for an accurate diagnosis and a precise monitoring of pediatric bone status.

Bone geometry in young male and female football players: a peripheral quantitative computed tomography (pQCT) study

The present study shows that football practice during growth may improve bone geometry in male and female football players. However, only females had better bone strength in comparison with controls.

PURPOSE

The aim of this study was to compare bone geometry in adolescent football players and controls.

METHODS

A total of 107 football players (71 males/36 females; mean age 12.7 ± 0.6/12.7 ± 0.6 years) and 42 controls (20 males/22 females; mean age 13.1 ± 1.4/12.7 ± 1.3 years) participated in this study. Total and trabecular volumetric bone mineral content (Tt.BMC/Tb.BMC), cross-sectional area (Tt.Ar/Tb.Ar), and bone strength index (BSI) were measured at 4% site of the non-dominant tibia by peripheral quantitative computed tomography (pQCT). Moreover, Tt.BMC, cortical BMC (Ct.BMC), Tt.Ar, cortical Ar (Ct.Ar), cortical thickness (Ct.Th), periosteal circumference (PC), endosteal circumference (EC), fracture load in X-axis, and polar strength strain index (SSIp) were measured at 38% site of the tibia. Multivariate analyses of covariance were used to compare bone pQCT variables between football players and controls using the tibia length and maturity offset as covariates.

RESULTS

Female football players demonstrated 13.8-16.4% higher BSI, Ct.Th, fracture load in X-axis, and SSIp than controls (p < .0036). Males showed no significant differences in bone strength when compared to controls (p > .0036). In relation to bone mineral content and area, male football players showed 8.8% higher Tt.Ar and Tb.Ar at the 4% site of the tibia when compared to controls; whereas 13.8-15.8% higher Tt.BMC, Ct.BMC, and Ct.Ar at the 38% site of the tibia were found in female football players than controls (p < .0036).

CONCLUSIONS

In this study, female adolescent football players presented better bone geometry and strength values than controls. In contrast, only bone geometry was higher in male football players than controls.

Bone protective agents in children

Evaluation of bone health in childhood is important to identify children who have inadequate bone mineralisation and who may benefit from interventions to decrease their risk of osteoporosis and subsequent fracture. There are no bone protective agents that are licensed specifically for the prevention and treatment of osteoporosis in children. In this review, we discuss the mechanism of action and use of bisphosphonates and other new and established bone protective agents in children.

Are there effects of age, gender, height, and body fat on the functional muscle-bone unit in children and adults?

The aim was to describe the effect of age, gender, height, different stages of human life, and body fat on the functional muscle-bone unit. All these factors had a significant effect on the functional muscle-bone unit and should be addressed when assessing functional muscle-bone unit in children and adults.

INTRODUCTION

For the clinical evaluation of the functional muscle-bone unit, it was proposed to evaluate the adaptation of the bone to the acting forces. A frequently used parameter for this is the total body less head bone mineral content (TBLH-BMC) determined by dual-energy X-ray absorptiometry (DXA) in relation to the lean body mass (LBM by DXA). LBM correlates highly with muscle mass. Therefore, LBM is a surrogate parameter for the muscular forces acting in everyday life. The aim of the study was to describe the effect of age and gender on the TBLH-BMC for LBM and to evaluate the impact of other factors, such as height, different stages of human life, and of body fat.

METHODS

As part of the National Health and Nutrition Examination Survey (NHANES) study, between the years 1999-2006 whole-body DXA scans on randomly selected Americans from 8 years of age were carried out. From all eligible DXA scans (1999-2004), three major US ethnic groups were evaluated (non-Hispanic Whites, non-Hispanic Blacks, and Mexican Americans) for further statistical analysis.

RESULTS

For the statistical analysis, the DXA scans of 8190 non-Hispanic White children and adults (3903 female), of 4931 non-Hispanic Black children and adults (2250 female) and 5421 of Mexican-American children and adults (2424 female) were eligible. Age, gender, body height, and especially body fat had a significant effect on the functional muscle-bone unit.

CONCLUSIONS

When assessing TBLH-BMC for LBM in children and adults, the effects of age, gender, body fat, and body height should be addressed. These effects were analyzed for the first time in such a large cohort.

Lumbar spine bone mineral density Z-score discrepancies by dual X-ray absorptiometry do not predict vertebral fractures in children

Dual X-ray absorptiometry (DXA) remains the most common mode of bone mineral density (BMD) evaluation. In adults, presence of a lumbar spine (LS) BMD T-score discrepancy (>1 SD difference between adjacent vertebrae) can indicate a vertebral fracture. In children, however, the clinical significance of such discrepancies is unknown. We conducted a retrospective study to evaluate the association between LS DXA and LS morphology to elucidate the clinical significance of an LS BMD Z-score discrepancy. We identified 360 DXA scans performed between September 2014 and May 2016 in patients 5-18 years of age. DXA scans were cross-referenced against available LS radiographs and vertebral fracture assessment (VFA) within the 6 months preceding or following a DXA scan. After excluding 44 DXA scans because of spinal hardware, incomplete DXA, or repeat scans, 316 DXA scans were included; 81 (25.6%) had either an LS radiograph or a VFA. Twenty-five of 81 patients (30.9%) had >1 SD difference between adjacent vertebrae in LS BMD Z-score. Two of these 25 patients (8%) had a lumbar vertebral fracture documented by a spine radiograph. Of the remaining 56 patients who did not have a discrepancy >1 SD, 6 patients (11%) had a lumbar vertebral fracture. Discrepancies in LS BMD Z-scores were not associated with lumbar vertebral fractures and, in the absence of fractures, likely represented vertebral developmental variants in children whose skeletons are still growing. Therefore, it does not appear justified to recommend further imaging based solely on the results of a DXA scan without clinically meaningful indications.

Body fat mass, lean body mass and associated biomarkers as determinants of bone mineral density in children 6-8years of age - The Physical Activity and Nutrition in Children (PANIC) study

Lean body mass (LM) has been positively associated with bone mineral density (BMD) in children and adolescents, but the relationship between body fat mass (FM) and BMD remains controversial. Several biomarkers secreted by adipose tissue, skeletal muscle, or bone may affect bone metabolism and BMD. We investigated the associations of LM, FM, and such biomarkers with BMD in children. We studied a population sample of 472 prepubertal Finnish children (227 girls, 245 boys) aged 6-8years. We assessed BMD, LM, and FM using whole-body dual-energy x-ray absorptiometry and analysed several biomarkers from fasting blood samples. We studied the associations of LM, FM, and the biomarkers with BMD of the whole body excluding the head using linear regression analysis. LM (standardized regression coefficient β=0.708, p<0.001), FM (β=0.358, p<0.001), and irisin (β=0.079, p=0.048) were positive correlates for BMD adjusted for age, sex, and height in all children. These associations remained statistically significant after further adjustment for LM or FM. The positive associations of dehydroepiandrosterone sulphate (DHEAS), insulin, homeostatic model assessment for insulin resistance (HOMA-IR), leptin, free leptin index, and high-sensitivity C-reactive protein and the negative association of leptin receptor with BMD were explained by FM. The positive associations of DHEAS and HOMA-IR with BMD were also explained by LM. Serum 25-hydroxyvitamin D was a positive correlate for BMD adjusted for age, sex, and height and after further adjustment for FM but not for LM. LM and FM were positive correlates for BMD also in girls and boys separately. In girls, insulin, HOMA-IR, leptin, and free leptin index were positively and leptin receptor was negatively associated with BMD adjusted for age, height, and LM. After adjustment for age, height, and FM, none of the biomarkers was associated with BMD. In boys, leptin and free leptin index were positively and leptin receptor was negatively associated with BMD adjusted for age, height, and LM. After adjustment for age, height and FM, 25(OH)D was positively and IGF-1 and leptin were negatively associated with BMD. FM strongly modified the association between leptin and BMD. LM but also FM were strong, independent positive correlates for BMD in all children, girls, and boys. Irisin was positively and independently associated with BMD in all children. The associations of other biomarkers with BMD were explained by LM or FM.

Soccer helps build strong bones during growth: a systematic review and meta-analysis

The aim of this study was to analyze the effects of soccer practice on bone in male and female children and adolescents. MEDLINE, PubMed, SPORTDiscus and Web of Science databases were searched for scientific articles published up to and including October 2016. Twenty-seven studies were included in this systematic review (13 in the meta-analysis). The meta-analysis was performed by using OpenMeta[Analyst] software. It is well documented that soccer practice during childhood provides positive effects on bone mineral content (BMC) and density (BMD) compared to sedentary behaviors and other sports, such as tennis, weightlifting, or swimming. Furthermore, soccer players present higher BMC and BMD in most weight-bearing sites such as the whole body, lumbar spine, hip, and legs. Moreover, bone differences were minimized between groups during prepuberty. Therefore, the maturity status should be considered when evaluating bone. According to meta-analysis results, soccer practice was positively associated with whole-body BMD either in males (mean difference 0.061; 95%CI, 0.042-0.079) or in females (mean difference 0.063; 95%CI, 0.026-0.099).

CONCLUSION

Soccer may be considered a sport that positively affects bone mass during growth. Pubertal soccer players presented increased bone mass compared to controls or other athletes; however, these bone differences are minimized during the prepubertal stage. What is known: • It has been described that childhood and adolescence are important periods for bone mass and structure. • Previous studies have demonstrated that soccer participation improves bone mass in male and female children and adolescents. What is new: • The differences between soccer players and controls are more marked during puberty than prepuberty. • Weight-bearing sites such as lumbar spine, hip, femoral neck, trochanter, intertrochanteric region and both legs are particularly sensitive to soccer actions.

Increases in IGF-1 After Anti-TNF-α Therapy Are Associated With Bone and Muscle Accrual in Pediatric Crohn Disease

CONTEXT

Low levels of insulinlike growth factor 1 (IGF-1) in pediatric and adolescent Crohn disease (CD) likely contribute to bone and muscle deficits.

OBJECTIVE

Assess changes in IGF-1 levels and associations with bone and muscle accrual following initiation of anti-tumor necrosis factor α (TNF-α) therapy in pediatric and adolescent CD.

DESIGN AND PARTICIPANTS

Participants (n = 75, age 5 to 21 years) with CD were enrolled in a prospective cohort study; 63 completed the 12-month visit.

MAIN OUTCOME MEASURES

IGF-1 levels at baseline and 10 weeks, as well as dual-energy x-ray absorptiometry (DXA) and tibia peripheral quantitative computed tomography (pQCT) measures of bone and muscle at baseline and 12 months after initiation of anti-TNF-α therapy. Outcomes were expressed as sex-specific z scores.

RESULTS

IGF-1 z scores increased from a median (interquartile range) of -1.0 (-1.58 to -0.17) to -0.36 (-1.04 to 0.36) over 10 weeks (P < 0.001). Lesser disease severity and systemic inflammation, as well as greater estradiol z scores (in girls), was significantly associated with greater IGF-1 z scores over time. DXA whole-body bone mineral content, leg lean mass, and total hip and femoral neck bone mineral density (BMD) z scores were low at baseline (P < 0.0001 vs reference data) and increased significantly (P < 0.001) over 12 months. Greater increases in IGF-1 z scores over 10 weeks predicted improvement in DXA bone and muscle outcomes and pQCT trabecular BMD and cortical area. Adjustment for changes in muscle mass markedly attenuated the associations between IGF-1 levels and bone outcomes.

CONCLUSIONS

Short-term improvements in IGF-1 z scores predicted recovery of bone and muscle outcomes following initiation of anti-TNF-α therapy in pediatric CD. These data suggest that disease effects on growth hormone metabolism contribute to musculoskeletal deficits in CD.

Evaluation and Management of Primary Ovarian Insufficiency in Adolescents and Young Adults

STUDY OBJECTIVE

To identify clinical features associated with primary ovarian insufficiency (POI) and collect data on the evaluation and treatment received.

DESIGN

Retrospective chart review. Data were abstracted on etiology of POI, history, laboratory evaluation, imaging results, return for clinical care, and treatment plans.

SETTING

Urban children's hospital in Cincinnati, Ohio.

PARTICIPANTS

Fifty female patients, age 11-26 years, with initial presentation of POI between January 1, 2006 and December 31, 2015.

MAIN OUTCOME MEASURES

Etiology of POI, bone mineral density (BMD), laboratory evaluation, and services utilized at presentation.

RESULTS

Three hundred thirty-one charts were reviewed, 71 with confirmed diagnosis of POI, and 50 with sufficient data for inclusion. Among the 50, 21 (42%) had Turner syndrome, 18 (36%) remained idiopathic, and 11 (22%) had another condition (eg, autoimmune polyglandular syndrome, galactosemia, etc). Thirty-six (72%) were karyotyped; in 14 (28%), 21-hydroxylase antibodies were measured; 32 (64%) underwent dual-energy x-ray absorptiometry BMD measures of lumbar spine. Eight of 50 patients (16%) reported fracture. Of these, at presentation, 4 (50%) had low BMD, and 2 (25%) had slightly low BMD. On initial spinal dual-energy x-ray absorptiometry, 9 of 32 (28%) had low BMD (Z-score ≤ -2.0) and 7 of 32 (22%) were slightly low (-1.0 to -1.9). All started estrogen therapy within 2 years of presentation. In follow-up, only 2 patients (4%) saw a mental health consultant for emotional support.

CONCLUSION

POI is a model of estrogen deficiency with most cases due to Turner syndrome or idiopathic causes. At presentation, many had low BMD and few were seen for psychological support as part of multidisciplinary care.

Scanning Skeletal Remains for Bone Mineral Density in Forensic Contexts

The purpose of this paper is to introduce a promising, novel method to aid in the assessment of bone quality in forensically relevant skeletal remains. BMD is an important component of bone's nutritional status and in skeletal remains of both juveniles and adults, and it can provide information about bone quality. For adults remains, it can provide information on pathological conditions or when bone insufficiency may have occurred. In juveniles, it provides a useful metric to elucidate cases of fatal starvation or neglect, which are generally difficult to identify. This paper provides a protocol for the anatomical orientation and analysis of skeletal remains for scanning via dual-energy X-ray absorptiometry (DXA). Three case studies are presented to illustrate when DXA scans can be informative to the forensic practitioner. The first case study presents an individual with observed longitudinal fractures in the weight bearing bones and DXA is used to assess bone insufficiency. BMD is found to be normal suggesting another etiology for the fracture pattern present. The second case study employed DXA to investigate suspected chronic malnutrition. The BMD results are consistent with results from long bone lengths and suggest the juvenile had suffered from chronic malnutrition. The final case study provides an example where fatal starvation in a fourteen-month infant is suspected, which supports autopsy findings of fatal starvation. DXA scans showed low bone mineral density for chronological age and is substantiated by traditional assessments of infant health. However, when dealing with skeletal remains taphonomic alterations should be considered before applying this method.

Generalized metabolic bone disease and fracture risk in Rothmund-Thomson syndrome

Rothmund-Thomson syndrome (RTS) is a rare autosomal recessive disorder characterized by poikiloderma, small stature, sparse hair, skeletal abnormalities, increased risk of osteosarcoma, and decreased bone mass. To date, there has not been a comprehensive evaluation of the prevalence and extent of metabolic bone disease in RTS. Furthermore, the mechanisms that result in this phenotype are largely unknown. In this report, we provide a detailed evaluation of 29 individuals with RTS with respect to their metabolic bone status including bone mineral density, calcium kinetics studies, and markers of bone remodeling. We show that individuals with RTS have decreased areal bone mineral density. Additionally, we demonstrate that the presence of pathogenic variants in RECQL4 and low bone mineral density correlate with the history of increased risk of fractures. Using a RECQL4-deficient mouse model that recapitulates skeletal abnormalities seen in individuals with RTS, we demonstrate that generalized skeletal involvement is likely due to decreased osteogenesis. Our findings are clinically relevant as they may help in the risk stratification of patients with RTS and also in the identification of individuals who may benefit from additional surveillance and management of metabolic bone disease.

Dyslipidemia, chronic inflammation, and subclinical atherosclerosis in children and adolescents infected with HIV: The PositHIVe Health Study

HIV-infected children and adolescents may be at risk for cardiovascular disease due to chronic inflammation and exacerbation of risk factors. The aim of this study was as follows: 1) compare cardiovascular risk factors, chronic inflammation, and carotid intima-media thickness (IMTc) between the HIV and control groups; 2) determine the association of HIV and antiretroviral (ART) regimens with cardiovascular risk factors, chronic inflammation, and IMTc; and 3) identify variables associated with elevated IMTc. Cross-sectional analysis of 130 children and adolescents, 8-15 years of age, divided into HIV-infected (n = 65) and healthy control (n = 65) participants. Body fat, blood pressure, glycemia, insulin, and glycated hemoglobin, total cholesterol and fractions (LDL-C and HDL-C), triglycerides, C-reactive protein (CRP), interleukin (IL)-6, tumor necrosis factor-alpha (TNF-α), and the IMTc were measured. The results showed HIV-infected children and adolescents had higher levels of glycemia (87.9 vs. 75.9 mg.dL-1, p< 0.001), LDL-c (94.7 vs. 79.5 mg.dL-1, p = 0.010), triglycerides (101.2 vs. 61.6 mg.dL-1, p< 0.001), CRP (1.6 vs. 1.0 mg.L-1, p = 0.007), IL-6 (1.42 vs. 0.01 pg.mL-1, p< 0.001), TNF-α (0.49 vs. 0.01 pg.mL-1, p< 0.001), mean IMTc (0.526 vs. 0.499 mm, p = 0.009), and lower HDL-c (53.7 vs. 69.4 mg.dL-1, p< 0.001) compared to controls. Systolic blood pressure (β = 0.006, p = 0.004) and TNF-α (β = -0.033, p = 0.029) accounted for 16% of IMTc variability in HIV-infected children and adolescents. In patients using protease inhibitors-based ART, male gender (β = -0.186, p = 0.008), trunk body fat (β = -0.011, p = 0.006), glucose (β = 0.005, p = 0.046), and IL-6 (β = 0.017, p = 0.039) accounted for 28% of IMTc variability. HIV-infected children and adolescents may be at risk for premature atherosclerosis due to chronic inflammation and dyslipidemia. Interventions with the potential to improve lipid profile, mitigate inflammation, and reduce cardiovascular risk are needed.

Proceedings of the 2017 Santa Fe Bone Symposium: Insights and Emerging Concepts in the Management of Osteoporosis

The 18th Annual Santa Fe Bone Symposium was held on August 4-5, 2017, in Santa Fe, New Mexico, USA. The symposium convenes health-care providers and clinical researchers to present and discuss clinical applications of recent advances in research of skeletal diseases. The program includes lectures, oral presentations by endocrinology fellows, case-based panel discussions, and breakout sessions on topics of interest, with emphasis on participation and interaction of all participants. Topics included the evaluation and treatment of adult survivors with pediatric bone diseases, risk assessment and management of atypical femur fractures, nonpharmacologic strategies in the care of osteoporosis, and skeletal effects of parathyroid hormone with opportunities for therapeutic intervention. Management of skeletal complications of rheumatic diseases was discussed. Insights into sequential and combined use of antiresorptive agents were presented. Individualization of patient treatment decisions when clinical practice guidelines may not be applicable was covered. Challenges and opportunities with osteoporosis drug development were discussed. There was an update on progress of Bone Health TeleECHO (Bone Health Extension for Community Healthcare Outcomes), a teleconferencing strategy for sharing knowledge and expanding capacity to deliver best-practice skeletal health care.

Prevalence of low bone mass among adolescents with nontransfusion-dependent hemoglobin E/β-thalassemia and its relationship with anemia severity

BACKGROUND

Low bone mass is common among adolescents with transfusion-dependent β-thalassemia despite adequate transfusion and iron chelation. However, there are few reports regarding bone mineral density (BMD) among adolescents with nontransfusion-dependent thalassemia (NTDT). Indeed, only BMD data in patients with nontransfusion-dependent (NTD) β-thalassemia intermedia have been reported. No previous study has investigated BMD among adolescents with NTD hemoglobin (Hb) E/β-thalassemia.

OBJECTIVE

To determine the prevalence of low bone mass among adolescents with NTD Hb E/β-thalassemia and factors relating to low bone mass.

METHODS

We investigated BMD of lumbar spine (L2-L4; BMDLS) and total body (BMDTB), as measured by dual-energy X-ray absorptiometry, in 22 adolescents (aged 13.2-20 years) with NTD Hb E/β-thalassemia.

RESULTS

Low bone mass was found to be 18.2% and 22.7% at the lumbar spine (BMDLS Z-score adjusted for bone age and height age) and 13.6% and 9.1% at the total body (BMDTB Z-score adjusted for bone age and height age). Patients with mean Hb level <8 g/dl were more likely to have low bone mass (BMDLS and BMDTB Z-scores adjusted for bone age) compared to those with Hb level ≥ 8 g/dl. Mean Hb level correlated with BMDLS and BMDTB Z-scores adjusted for bone age.

CONCLUSION

We demonstrated that a low Hb level was associated with low bone mass among adolescents with NTD Hb E/β-thalassemia. A significant proportion of low bone mass among these patients highlights the importance of appropriate management, including red cell transfusion, vitamin D and calcium supplementation for improved long-term bone health.

Determinants of low bone mineral density in children with epilepsy

INTRODUCTION

Children with epilepsy on long-term antiepileptic drugs (AEDs) are at risk of low bone mineral density (BMD). The aims of our study were to evaluate the prevalence and determinants of low BMD among Malaysian children with epilepsy.

METHOD

Cross-sectional study of ambulant children with epilepsy on long-term AEDs for >1 year seen in a tertiary hospital in Malaysia from 2014 to 2015. Detailed assessment of anthropometric measurements; environmental lifestyle risk factors; serum vitamin D, calcium and parathyroid hormone levels; genotyping of single nucleotide polymorphisms of genes in vitamin D and calcium metabolism; and lumbar spine BMD were obtained. Low BMD was defined as BMD Z-score ≤ -2.0 SD.

RESULTS

Eighty-seven children with mean age of 11.9 years (56 males) participated in the study. The prevalence of low lumbar BMD was 21.8% (19 patients). Multivariate logistic regression analysis identified polytherapy >2 AEDs (OR: 7.86; 95% CI 1.03-59.96), small frame size with wrist breadth of <15th centile (OR 14.73; 95% CI 2.21-98.40), and body mass index Z-score < -2.0 (OR 8.73, 95% CI 1.17-65.19) as significant risk factors for low BMD.

CONCLUSION

One-fifth of Malaysian children with epilepsy on long-term AEDs had low BMD. Targeted BMD should be performed for those who are on >2 AEDs, underweight or with small frame size as they are at higher risk of having low BMD.

Effects of interventions with a physical activity component on bone health in obese children and adolescents: a systematic review and meta-analysis

Given the rise in pediatric obesity, clarifications on the relationship between obesity and bone health and on the impact of structured intervention on this relationship are needed. This systematic review and meta-analysis investigated the effect of obesity on bone health and assessed the effect of structured intervention in children and adolescents with obesity. Medline complete, OVID, CINAHL, EMBASE and PubMed databases were searched for studies on obesity and bone health variables up to September 2016, then an update occurred in March 2016. Search items included obesity, childhood, dual energy X-ray absorptiometry and peripheral quantitative computed tomography. Twenty-three studies (14 cross-sectional and nine longitudinal) matched the inclusion criteria. Results from the meta-analysis (cross-sectional studies) confirmed that children and adolescents with obesity have higher bone content and density than their normal weight peers. Results from longitudinal studies remain inconclusive as only 50% of the included studies reported a positive effect of a structured intervention program on bone health. As such, the meta-analysis reported that structured intervention did not influence bone markers despite having beneficial effects on general health in youth with obesity.

Bone Health and Endocrine Care of Boys with Duchenne Muscular Dystrophy: Data from the MD STARnet

BACKGROUND

Patients with Duchenne muscular dystrophy (DMD) are at high risk of endocrine and bone health complications resulting from the high glucocorticoid (GC) doses used to treat this condition. There are limited data characterizing the clinical management of these complications.

OBJECTIVE

To determine the frequency of bone health screening, endocrinologist evaluation, and use of endocrine and bone health pharmacotherapy in the clinical care of males with DMD.

METHODS

A population based cohort study using data from the Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet) was conducted. Clinical data was abstracted from the medical records of 683 males with DMD at five surveillance sites across the US.

RESULTS

A DXA scan had been documented in 24% of cases; the percentage of cases with DXA varied across surveillance sites from 13% to 43%, p < 0.001. History of fracture and greater disease duration were associated with greater odds of having a DXA. Only 4.7% of cases had documentation of an endocrinologist evaluation. The frequency of documented endocrine and bone health pharmacotherapy use included calcium (42.8%), vitamin D (36.6%), bisphosphonates (13.3%), growth hormone (1.9%), testosterone (1.7%), insulin (1.2%), and metformin (0.3%)Conclusions:A low percentage of DMD males had record of DXA scan, endocrinologist evaluation, or treatment with endocrine or bone health pharmacotherapy. Endocrine and bone health care may represent an unmet need in the DMD population.

Longitudinal determinants of 12-month changes on bone health in adolescent male athletes

We identified the determinants of 12-month changes of areal bone mineral density (aBMD), hip geometry and trabecular bone score (TBS) in adolescent male athletes. Changes in region-specific lean mass and the type of sport are the most consistent determinants in this population.

PURPOSE

This study aims to identify the determinants of 12-month changes of areal bone mineral density (aBMD), hip geometry and trabecular bone score (TBS) in adolescent male athletes.

METHODS

The sample was 104 adolescent males aged 12-14 years at baseline that were followed over 12 months: 39 swimmers, 37 footballers (or soccer players) and 28 cyclists. Dual-energy X-ray absorptiometry measured aBMD at the whole body, lumbar spine and dual hip. Hip geometry estimates at the femoral neck were measured using hip structural analysis. Lumbar spine texture was measured by TBS.

RESULTS

Multivariate regression models significantly explained 38-60% of the variance in the aBMD changes, 36-62% in the hip geometry estimates changes and 45% in the TBS changes. Δregion-specific lean mass was the most consistent predictor of changes in aBMD outcomes (β = 0.591 to 0.696), followed by cycling participation (β = - 0.233 to - 0.262), swimming participation (β = - 0.315 to - 0.336) and ΔMVPA (β = 0.165). Cycling participation was the most consistent predictor of changes in hip geometry estimates (β = - 0.174 to - 0.268), followed by Δregion-specific lean mass (β = 0.587) and Δcardiorespiratory fitness (β = 0.253). Finally, cycling and swimming participation (β = - 0.347 to - 0.453), Δregion-specific lean mass (β = 0.848) and Δstature (β = 0.720) were predictors of change in TBS.

CONCLUSIONS

Changes in region-specific lean mass and the type of sport are the most consistent determinants of 12-month changes in aBMD, hip geometry estimates and TBS in adolescent male athletes.

TRIAL REGISTRATION

ISRCTN17982776.

The effect of a high-impact jumping intervention on bone mass, bone stiffness and fitness parameters in adolescent athletes

This study demonstrates that a 9-month jumping intervention can improve bone mass gains and physical fitness performance in adolescent males participating in non-osteogenic sports, such as swimming and cycling.

PURPOSE

To examine the effect of a jumping intervention on bone mass, bone stiffness and fitness parameters in adolescents involved in different sports.

METHODS

Ninety-three adolescent male swimmers (SWI), footballers (FOO) and cyclists (CYC) were randomised to intervention (INT) and sport (INT-SWI = 19, INT-FOO = 15, INT-CYC = 14) or sport only (CON-SWI = 18, CON-FOO = 15, CON-CYC = 12) groups. The 9-month jumping intervention consisted of 3 levels (12 weeks each) of 20 repetitions per set of counter movement jumps (CMJ) using adjustable weight vests (level 1 = 20 CMJ jumps/set, 0 kg, 3 sets/day, 3 times/week; level 2 = 20 CMJ jumps/set, 2 kg, 4 sets/day, 3 times/week; level 3 = 20 CMJ jumps/set, 5 kg, 4 sets/day, 4 times/week). Total body bone mineral content (BMC) at total body less head (TBLH) was measured using dual-energy X-ray absorptiometry and bone stiffness using quantitative ultrasound. Fitness was assessed using the 20-m shuttle run (20mSRT), CMJ and standing long jump (SLJ) tests.

RESULTS

INT-SWI had significantly higher increase in BMC legs and bone stiffness compared to CON-SWI (4.2-12.7%). INT-CYC had significantly higher increase in BMC at TBLH and legs and bone stiffness compared to CON-CYC (5.0-12.3%). There were no significant differences between INT-FOO and CON-FOO in any bone outcomes (0.9-3.9%). The increase in CMJ performance was significantly higher in INT-SWI (3.1 cm) and INT-CYC (3.2 cm) compared to CON-SWI and CON-CYC groups, respectively.

CONCLUSIONS

A 9-month jumping intervention can improve bone mass, bone stiffness and muscular fitness in adolescent males participating in non-osteogenic sports, such as swimming and cycling.

CLINICAL TRIAL REGISTRATION

ISRCTN17982776.

Low Bone Mineral Density in Male Athletes Is Associated With Bone Stress Injuries at Anatomic Sites With Greater Trabecular Composition

BACKGROUND

While sports participation is often associated with health benefits, a subset of athletes may develop impaired bone health. Bone stress injuries (BSIs) are a common overuse injury in athletes; site of injury has been shown to relate to underlying bone health in female athletes. Hypothesis/Purpose: This case series characterizes the association of type of sports participation and anatomic site of BSIs with low bone mineral density (BMD), defined as BMD Z-score <-1.0. Similar to female athletes, it was hypothesized that male athletes who participate in running and sustain BSIs in sites of higher trabecular bone content would be more likely to have low BMD.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Chart review identified 28 male athletes aged 14 to 36 years with history of ≥1 lower-extremity BSI who were referred for evaluation of overall bone health, including assessment of lumbar spine, hip, and/or total body less head BMD per dual-energy x-ray absorptiometry. BMD Z-scores were determined via age, sex, and ethnicity normative values. Prior BSIs were classified by anatomic site of injury into trabecular-rich locations (pelvis, femoral neck, and calcaneus) and cortical-rich locations (tibia, fibula, femur, metatarsal and tarsal navicular). Sport type and laboratory values were also assessed in relationship to BMD. The association of low BMD to anatomic site of BSI and sport were evaluated with P value <.05 as threshold of significance.

RESULTS

Of 28 athletes, 12 (43%) met criteria for low BMD. Athletes with a history of trabecular-rich BSIs had a 4.6-fold increased risk for low BMD as compared with those with only cortical-rich BSIs (9 of 11 vs 3 of 17, P = .002). Within sport type, runners had a 6.1-fold increased risk for low BMD versus nonrunners (11 of 18 vs 1 of 10, P = .016). Laboratory values, including 25-hydroxy vitamin D, were not associated with BMD or BSI location.

CONCLUSION

Low BMD was identified in 43% of male athletes in this series. Athletes participating in sports of running and with a history of trabecular-rich BSI were at increased risk for low BMD.

Bone health and SATB2-associated syndrome

SATB2-associated syndrome (SAS) is a rare disorder caused by alterations in the special AT-rich sequence-binding protein 2 (SATB2). Skeletal abnormalities such as tibial bowing, osteomalacia, osteopenia or osteoporosis have been reported suggesting a higher frequency of skeletal complications in SAS. The optimal timing, necessity, and methodology for routine assessment of bone health in individuals with SAS, however, remain unclear. We report molecular and phenotypic features of 7 individuals with SAS documented to have low bone mineral density (BMD) ascertained by dual-energy X-ray absorptiometry (DXA), often preceded by tibial bowing. The lowest BMD Z-scores ranged -2.3 to -5.6. In 4 individuals, total alkaline phosphatase levels were elevated (2 with elevated bone fraction) around the time of low BMD documentation. A clinically significant fracture history and a diagnosis of pediatric osteoporosis were present in 4 individuals. Pamidronate treatment in 2 children improved BMD. In conclusion, low BMD, fractures, and tibial bowing are relatively common skeletal complications in individuals with SAS. DXA is a useful tool when evaluating a child with SAS suspected to have low BMD and the results might alter clinical management.

Rope skipping increases bone mineral density at calcanei of pubertal girls in Hong Kong: A quasi-experimental investigation

Bone mineral accrual during puberty is important, especially in girls, because it is related to reduced risks of osteoporosis in adulthood. Previous research has shown that jumping or plyometric exercises may be effective in increasing bone mineral density in adolescents. Rope skipping is a form of activity that involves jumping, thus regular skipping may also increase bone mineral density in pubertal girls. To this end, we conducted a quasi-experimental to examine the effects of rope skipping on girls' bone mineral density and cardiovascular fitness. 176 Hong Kong girls (age = 12.23 ± 1.80 years at baseline) were recruited to take part in the study. Bone density at their forearms and calcanei were measured twice over two academic years (mean time between visits was 10.3 months). Using multilevel modeling analyses and adjusting for participants' height and physical activity, we found that girls who participated in weekly rope skipping activities, compared to those who did not, had higher levels of bone density at the calcanei (B = 0.023, p < .01). However, no differences were found for bone density at forearms or participants' cardiovascular fitness. The rates of change of these variables across time were also not significantly different. Results suggest that regular rope skipping may increase girls' bone density at the lower extremities, irrespective of the amount of self-report physical activity. However, further research is required to examine the potential dose-response relation between skipping behaviors and the measured outcomes.

Weight Trajectories from Birth and Bone Mineralization at 7 Years of Age

OBJECTIVE

To assess whether different trajectories of weight gain since birth influence bone mineral content (BMC) and areal bone mineral density (aBMD) at 7 years of age.

STUDY DESIGN

We studied a subsample of 1889 children from the Generation XXI birth cohort who underwent whole-body dual-energy radiograph absorptiometry. Weight trajectories identified through normal mixture modeling for model-based clustering and labeled "normal weight gain," "weight gain during infancy," "weight gain during childhood," and "persistent weight gain" were used. Differences in subtotal BMC, aBMD, and size-corrected BMC (scBMC) at age 7 years according to weight trajectories were estimated through analysis of covariance.

RESULTS

Compared with the "normal weight gain" trajectory, children in the remaining trajectories had significantly greater BMC, aBMD, and scBMC at age 7 years, with the strongest associations for "persistent weight gain" (girls [BMC: 674.0 vs 559.8 g, aBMD: 0.677 vs 0.588 g/cm², scBMC: 640.7 vs 577.4 g], boys [BMC: 689.4 vs 580.8 g, aBMD: 0.682 vs 0.611 g/cm², scBMC: 633.0 vs 595.6 g]). After adjustment for current weight, and alternatively for fat and lean mass, children with a "weight gain during childhood" trajectory had greater BMC and aBMD than those with a "normal weight gain" trajectory, although significant differences were restricted to girls (BMC: 601.4 vs 589.2 g, aBMD: 0.618 vs 0.609 g/cm²).

CONCLUSION

Overall, children following a trajectory of persistent weight gain since birth had clearly increased bone mass at 7 years, but weight gain seemed slightly more beneficial when it occurred later rather than on a normal trajectory during the first 7 years of life.

The history of bone densitometry

Bone densitometry (dual energy x-ray absorptiometry-DXA) is a vital medical tool needed for the diagnosis of osteoporosis in non-fractured patients; predicting future fracture risk; and monitoring bone mineral density (BMD) in untreated or treated patients. The history of the pivotal international society involved in the science and clinical interpretation of DXA, the International Society for Clinical Densitometry (ISCD) is defined in this manuscript. Since DXA and Osteoporosis management are intimately linked, the ISCD has over the years developed strong bonds with both the National Osteoporosis Foundation (NOF) and the International Osteoporosis Foundation (IOF). The positive impact that ISCD has led in the proper performance and clinical interpretation of bone mass measurements has been enormous worldwide.

Use of dual energy X-ray absorptiometry in pediatric patients

Dual Energy X-ray Absorptiometry (DXA) is a vital tool for assessing bone health in patients at risk for fragility fractures. In pediatric patients, this technology is used in conjunction with clinical fracture history to diagnosis osteoporosis and monitor treatment response. Childhood and adolescence is characterized by linear growth and bone mass accrual; thus there are important differences in the interpretation of bone measurements obtained by DXA in these young patients. This review aims to explore the current indications for DXA use and interpretation of DXA in the pediatric age group using currently available reference databases. Limitations of DXA in pediatric patients, specifically in children with short stature, will be explored. We will review several pathophysiologic mechanisms that may lead to low bone density in children, discussing representative diseases and the recommendations for monitoring bone health with DXA in these conditions. Finally, we will highlight new methods by which DXA imaging can gather additional information on bone health in children and may improve our ability to predict fractures and osteoporosis.

Longitudinal Adaptations of Bone Mass, Geometry, and Metabolism in Adolescent Male Athletes: The PRO-BONE Study

Adolescence is a crucial period for bone development, and exercise can enhance bone acquisition during this period of life. However, it is not known how the different loading sports practiced can affect bone acquisition in adolescent male athletes. Therefore, the purpose of the present study was to determine the 1-year longitudinal bone acquisition among adolescent males involved in osteogenic (football) and non-osteogenic (swimming and cycling) sports and to compare with active controls. A total of 116 adolescent males aged 12 to 14 years at baseline were followed for 1 year: 37 swimmers, 37 footballers, 28 cyclists, and 14 active controls. Bone mineral content (BMC) was assessed using dual-energy X-ray absorptiometry (DXA); cross-sectional area (CSA), cross-sectional moment of inertia (CSMI), and section modulus (Z) at the femoral neck was assessed using hip structural analysis (HSA); and bone texture of the lumbar spine was assessed using trabecular bone score (TBS). Serum N-terminal propeptide of procollagen type I (PINP), isomer of the Carboxi-terminal telopeptide of type 1 collagen (CTX-I), total serum calcium, and 25 hydroxyvitamin D [25(OH)D] were analyzed. Footballers had significantly higher adjusted BMC at the lumbar spine (7.0%) and femoral neck (5.0%) compared with cyclists, and significantly greater BMC at the lumbar spine (6.9%) compared with swimmers. Footballers presented significantly greater TBS (4.3%) compared with swimmers, and greater CSMI (10.2%), CSA (7.1%), Z (8.9%) and TBS (4.2%) compared with cyclists. No differences were noted between cyclists and swimmers, both groups had similar bone acquisition compared with controls. PINP was significantly higher in footballers and controls compared with cyclists and swimmers (3.3% to 6.0%), and 25(OH)D was significantly higher in footballers and cyclists compared with swimmers and controls (9.9% to 13.1%). These findings suggest that bone acquisition is higher in adolescent male footballers compared with swimmers and cyclists at the femoral neck and lumbar spine sites of the skeleton. © 2017 American Society for Bone and Mineral Research.

Physical activity and bone mineral density at the femoral neck subregions in adolescents with Down syndrome

BACKGROUND

Low bone mineral density (BMD) has been frequently described in subjects with Down syndrome (DS). Reduced physical activity (PA) levels may contribute to low BMD in this population. The objective of the study was to investigate whether PA levels were related to the femoral neck bone mass distribution in a sample of 14 males and 12 females with DS aged 12-18 years.

METHODS

BMD was evaluated by dual energy X-ray absorptiometry (DXA) at the integral, superolateral and inferomedial femoral neck regions and PA levels were assessed by accelerometry. The BMDs between the sexes and PA groups (below and above the 50th percentile of the total PA) were compared using independent t-tests and analyses of covariance (ANCOVAs) controlling for age, height and body weight.

RESULTS

No differences were found between the BMDs of males and females in any femoral neck region (p>0.05). Females with higher PA levels demonstrated increased integral (0.774 g/cm2 vs. 0.678 g/cm2) and superolateral femoral neck BMDs (0.696 g/cm2 vs. 0.595 g/cm2) compared to those with lower PA levels (p<0.05). In males, no differences (p<0.05) were found in the BMDs between the PA groups.

CONCLUSIONS

This investigation shows that females accumulating more total PA presented increased BMDs at the integral and superolateral femoral neck regions (14.1% and 17.0%, respectively) when compared to their less active peers. These data highlight the importance of PA in females with DS to counteract their low bone mass and to improve their bone health.

Constitutional bone impairment in Noonan syndrome

Noonan syndrome (NS) is an autosomal dominant trait characterized by genotypic and phenotypic variability. It belongs to the Ras/MAPK pathway disorders collectively named Rasopathies or neurocardiofaciocutaneous syndromes. Phenotype is characterized by short stature, congenital heart defects, facial dysmorphisms, skeletal and ectodermal anomalies, cryptorchidism, mild to moderate developmental delay/learning disability, and tumor predisposition. Short stature and skeletal dysmorphisms are almost constant and several studies hypothesized a role for the RAS pathway in regulating bone metabolism. In this study, we investigated the bone quality assessed by phalangeal quantitative ultrasound (QUS) and the metabolic bone profiling in a group of patients with NS, to determine whether low bone mineralization is primary or secondary to NS characteristics. Thirty-five patients were enrolled, including 20 males (55.6%) and 15 females (44.5%) aged 1.0-17.8 years (mean 6.4 ± 4.5, median 4.9 years). Each patients was submitted to clinical examination, estimation of the bone age, laboratory assays, and QUS assessment. Twenty-five percent of the cohort shows reduced QUS values for their age based on bone transmission time. Bone measurement were adjusted for multiple factors frequently observed in NS patients, such as growth retardation, delayed bone age, retarded puberty, and reduced body mass index, potentially affecting bone quality or its appraisal. In spite of the correction attempts, QUS measurement indicates that bone impairment persists in nearly 15% of the cohort studied. Our results indicate that bone impairment in NS is likely primary and not secondary to any of the phenotypic traits of NS, nor consistent with metabolic disturbances. © 2017 Wiley Periodicals, Inc.

The complete European guidelines on phenylketonuria: diagnosis and treatment

Phenylketonuria (PKU) is an autosomal recessive inborn error of phenylalanine metabolism caused by deficiency in the enzyme phenylalanine hydroxylase that converts phenylalanine into tyrosine. If left untreated, PKU results in increased phenylalanine concentrations in blood and brain, which cause severe intellectual disability, epilepsy and behavioural problems. PKU management differs widely across Europe and therefore these guidelines have been developed aiming to optimize and standardize PKU care. Professionals from 10 different European countries developed the guidelines according to the AGREE (Appraisal of Guidelines for Research and Evaluation) method. Literature search, critical appraisal and evidence grading were conducted according to the SIGN (Scottish Intercollegiate Guidelines Network) method. The Delphi-method was used when there was no or little evidence available. External consultants reviewed the guidelines. Using these methods 70 statements were formulated based on the highest quality evidence available. The level of evidence of most recommendations is C or D. Although study designs and patient numbers are sub-optimal, many statements are convincing, important and relevant. In addition, knowledge gaps are identified which require further research in order to direct better care for the future.

The Role of Overweight and Obesity on Bone Health in Korean Adolescents with a Focus on Lean and Fat Mass

As the associations between pediatric overweight/obesity and bone health remain controversial, we investigated the effects of overweight/obesity as well as lean mass (LM) and fat mass (FM) on bone parameters in adolescents. Bone parameters were evaluated using dual-energy X-ray absorptiometry (DXA) data of 982 adolescents (aged 12-19 years) from the Korea National Health and Nutrition Examination Survey (2009-2010). Z-scores for LM, FM, bone mass, bone mineral density (BMD), and bone mineral apparent density (BMAD) using Korean pediatric reference values were used for analysis. Adolescents with overweight/obesity had significantly higher bone mass and density of the total-body-less-head (TBLH), lumbar spine, and femur neck than underweight or normal-weight adolescents (P < 0.001) after adjusting for vitamin D deficiency, calcium intake, and insulin resistance in both sexes. LM was positively associated with bone parameters at all skeletal sites in both sexes (P < 0.001). FM was negatively related to TBLH BMD in boys (P = 0.018) but was positively associated to BMD and BMAD of the lumbar spine and femur neck in girls. In conclusion, overweight/obesity and LM play a positive role in bone health in adolescents. The effect of FM on bone parameters is sex- and site-specific.

Risk factors and surveillance for reduced bone mineral density in pediatric cancer survivors

BACKGROUND

Pediatric cancer survivors are at increased risk of developing low bone mineral density (BMD) due to cancer treatment. This study assessed the yield of screening for low BMD in pediatric-aged cancer survivors as per the Children's Oncology Group Long-Term Follow-Up (COG-LTFU) Guidelines, which recommend screening survivors who received steroids, methotrexate, or hematopoietic cell transplant (HCT).

METHODS

This is a retrospective cohort study of 475 pediatric blood cancer and noncentral nervous system solid tumor survivors screened for low BMD with dual-energy X-ray absorptiometry (DXA) as per the COG-LTFU Guidelines from 2003 to 2010. Risk factors for low BMD (DXA Z-score ≤-2) were evaluated by univariate and multivariate analysis.

RESULTS

The mean DXA Z-score was -0.1 for both whole body and lumbar spine measurements. Among at-risk survivors, 8.2% (39/475) had low BMD. Multivariate analysis of survivors with low BMD showed significant association with male gender (odds ratio [OR] 3.4, 95% confidence interval [CI], 1.3-9.0), exposure to total body irradiation (TBI), cranial, or craniospinal radiation (OR 5.2, 95% CI, 1.8-14.9), and gonadal dysfunction (OR 4.3, 95% CI, 1.4-13.0). Methotrexate exposure was not significantly associated with low BMD. Survivors receiving HCT had a reduced risk of low BMD (OR 0.2, 95% CI, 0.1-0.9).

CONCLUSION

The highest risk factors for low BMD were male gender, exposure to TBI, cranial, or craniospinal radiation, and gonadal dysfunction. Survivors receiving methotrexate or HCT therapy have the lowest risk for low BMD among those screened. Future studies should investigate risk of low BMD for survivors receiving HCT without radiation exposure.

Bone mineral density in patients with inherited bone marrow failure syndromes

BackgroundPatients with inherited bone marrow failure syndromes (IBMFS) may have several risk factors for low bone mineral density (BMD). We aimed to evaluate the prevalence of low BMD in IBMFS and determine the associated risk factors.MethodsPatients with IBMFS with at least one dual-energy X-ray absorptiometry (DXA) scan were evaluated. Diagnosis of each IBMFS, Fanconi anemia (FA), dyskeratosis congenita, Diamond-Blackfan anemia, and Shwachman-Diamond syndrome was confirmed by syndrome-specific tests. Data were gathered on age, height, and clinical history. DXA scans were completed at the lumbar spine, femoral neck, and forearm. BMD was adjusted for height (HAZ) in children (age ≤20 years). Low BMD was defined as a BMD Z-score and HAZ ≤-2 in adults and children, respectively, in addition to patients currently on bisphosphonate therapy.ResultsNine of thirty-five adults (26%) and eleven of forty children (27%) had low BMD. Adults with FA had significantly lower BMD Z-scores than those with other diagnoses; however, HAZ did not vary significantly in children by diagnosis. Risk factors included hypogonadism, iron overload, and glucocorticoid use.ConclusionsAdults and children with IBMFS have high prevalence of low BMD. Prompt recognition of risk factors and management are essential to optimize bone health.

Do bone mineral content and density determine fracture in children? A possible threshold for physical activity

BackgroundRelations between bone parameters, physical exertion, and childhood fractures are complex. We aimed to estimate the associations between fracture history and bone mineral content (BMC) and areal bone mineral density (aBMD) at 7 years of age, by levels of physical activity, as a proxy for trauma frequency.MethodsWe used data collected from 2,261 children of the Generation XXI birth cohort, assembled in 2005/6 in Porto, Portugal. At the age of 7 years (2012/4), fracture history, time spent per week in active play, and sports practice were reported by parents. Subtotal and lumbar spine (LS) BMC and aBMD were measured using whole-body dual-energy X-ray absorptiometry.ResultsBoys and girls in the highest categories of time spent in sports practice or active play generally had higher BMC and aBMD. Among girls, BMC and aBMD were protective of fracture only in the highest quarter of active play (>660 min/week)-odds ratios (OR; 95% confidence interval (95% CI)) for subtotal BMC=0.27 (0.11-0.67), subtotal aBMD=0.18 (0.06-0.49), and LS aBMD=0.41 (0.22-0.75). For boys in the highest quarter of sports practice (>240 min/week), subtotal and LS BMC were protective of fracture-OR=0.39 (0.16-0.98) and 0.51 (0.27-0.96), respectively.ConclusionIn prepubertal children, BMC and aBMD predicted fracture history only in the highest levels of physical activity.