Comparison of calcaneus ultrasound and dual X-ray absorptiometry in children at risk of osteopenia

A cross-sectional study of the relationship between recreational sporting activity and calcaneal bone density in adolescents and young adults

OBJECTIVE

Childhood and adolescence are critical periods of bone development. Sporting activity is thought to impact peak bone mass acquisition, but most studies have used dual-energy X-ray absorptiometry (DXA) to assess bone health and reported associations between bone mass and elite sporting activity. The objective of this study was instead to assess the relationship between recreational sporting activity (RSA) and another bone assessment, calcaneal quantitative ultrasound (cQUS), in adolescents and young adults.

METHODS

We related recreational sporting activity, assessed through a lifestyle questionnaire, to heel ultrasound bone parameters in a cohort of New Zealand students aged 16-35 years. Complete datasets with data on all relevant confounders (body mass index (BMI), pubertal timing, smoking status, and alcohol consumption) were available for 452 participants. cQUS was performed using a Lunar Achilles EX II machine to obtain bone parameters, broadband ultrasound attenuation (BUA), and speed of sound (SOS); stiffness index (SI) was derived from these measures. All descriptive statistics and statistical analyses were carried out using SPSS Statistics for Macintosh, Version 23.0 (IBM Corp., Armonk, NY, USA). Results are presented as p-values and 95% CI.

RESULTS

Reported lifetime sport participation declined after an individual's mid-teens. Bone cQUS parameters (SI and BUA and T-score) were all positively associated with BMI, and current physical activity (SI, SOS, BUA, T-score, and Z-score) with SI and SOS measures most strongly associated with current high impact and past recreational sporting activity (all p < 0.05).

CONCLUSION

Calcaneal heel ultrasound bone parameters were associated with physical activity, with SI and SOS rather than BUA more strongly related to current and past recreational sporting activity in young New Zealand adults.

The first step in an investigation of quantitative ultrasound as a technique for evaluating infant bone strength

This study's purpose is to evaluate whether bone speed of sound (SOS) data, a parameter of quantitative ultrasound, collected from an infant autopsy sample are comparable to data collected from healthy, living infants. We hypothesize that SOS values obtained from deceased term-born infants will fall within the normal range for healthy, living infants. The study sample consists of 351 deceased infants between the ages of 30 weeks gestation at birth to 1 year postnatal at the time of death receiving autopsies at the Harris County Institute of Forensic Sciences or Texas Children's Hospital in Houston, TX. Various multivariate and univariate statistics were used to examine the relationship between SOS and age, prematurity, and chronic illness. The results of an ANOVA comparing the study sample data to published data from healthy, living infants indicate the SOS data are comparable. Additionally, a MANOVA indicated significant differences in SOS related to prematurity (p = 0.001) and age (p < 0.001). Mean SOS was significantly greater among term-born infants (M = 3065.66, SD =165.05) than premature infants (M = 2969.71, SD =192.72). Age had a significant polynomial (cubic) relationship with SOS for both the premature and term groups (p < 0.001). Results suggest that bone from an infant autopsy sample is an appropriate surrogate to examine the relationship between SOS and determinants of bone strength. Therefore, future research will use this study sample to investigate the relationship between SOS and determinants of bone strength in infants.

Recent advancements in the analysis of bone microstructure: New dimensions in forensic anthropology

Bone is a mechanically active, three-dimensionally (3D) complex, and dynamic tissue that changes in structure over the human lifespan. Bone tissue exists and remodels in 3D and changes over time, introducing a fourth dimension. The products of the remodelling process, secondary and fragmentary osteons, have been studied substantially using traditional two-dimensional (2D) techniques. As a result, much has been learned regarding the biological information encrypted in the histomorphology of bone, yielding a wealth of information relating to skeletal structure and function. Three-dimensional imaging modalities, however, hold the potential to provide a much more comprehensive understanding of bone microarchitecture. The visualization and analysis of bone using high-resolution 3D imaging will improve current understandings of bone biology and have numerous applications in both biological anthropology and biomedicine. Through recent technological advancements, we can hone current anthropological applications of the analysis of bone microstructure and accelerate research into the third and fourth dimensional realms. This review will explore the methodological approaches used historically by anthropologists to assess cortical bone microstructure, spanning from histology to current ex vivo imaging modalities, discuss the growing capabilities of in vivo imaging, and conclude with an introduction of novel non-histological modalities for investigating bone quality.

Imaging methods for bone mass evaluation during childhood and adolescence: an update

The objective of the work was to prepare an update on imaging methods for bone evaluation during childhood and adolescence. The text was based on original and review articles on imaging methods for clinical evaluation of bone mass in children and adolescents up to 20 years old. They were selected from BIREME and PUBMED by means of the following keywords: bone density; osteoporosis/diagnosis; densitometry; tomography; ultrasonography; magnetic resonance imaging; and radiogrammetry and published in Portuguese or English, in the last 10 years (2006-2016). The article was organized into topics with the description of peculiarities, advantages and disadvantages of each imaging method and their possible clinical applicability. Despite the emergence of new technologies, dual energy X-ray absorptiometry (DXA) remains the gold standard method for low bone mass diagnosis in all age groups. However, interpretation is complex in children and adolescents and demands skilled people. Quantitative computed tomography (QCT) [central QCT, peripheral QCT (pQCT) and high resolution-pQCT (HR-pQCT)] and magnetic resonance imaging (MRI) evaluate real bone density, but are not yet available for routine use. Quantitative bone ultrasound (QUS) shows good perspectives for its use in primary prevention actions. Automated radiogrammetry shows promise as a method able to flag individuals who might benefit from a complete bone assessment, but the clinical value of the measures still needs to be established.

Bone status measured by quantitative ultrasound: a comparison with DXA in Thai children

BACKGROUND/OBJECTIVES

Quantitative ultrasound (QUS) is used to measure bone quality and is known to be safe, radiation free and relatively inexpensive compared with dual-energy X-ray absorptiometry (DXA) that is considered the gold standard for bone status assessments. However, there is no consensus regarding the validity of QUS for measuring bone status. The aim of this study was to compare QUS and DXA in assessing bone status in Thai children.

SUBJECTS/METHODS

A total of 181 Thai children (90 boys and 91 girls) aged 6 to 12 years were recruited. Bone status was measured by two different techniques in terms of the speed of sound (SOS) using QUS and bone mineral density (BMD) using DXA. Calcium intake was assessed by 24 h diet recall. Pearson's correlation, κ-statistic and Bland and Altman analysis were used to assess the agreement between the methods.

RESULTS

There was no correlation between the two different techniques. Mean difference (s.d.) of the Z-scores of BMD and SOS was -0.61 (1.27) that was different from zero (P<0.05). Tertiles of Z-scores of BMD and QUS showed low agreement (κ 0.022, P=0.677) and the limits of agreement in Bland and Altman statistics were wide.

CONCLUSIONS

Although QUS is easy and convenient to use, the SOS measurements at the radius seem not appropriate for assessing bone quality status.

Quantitative ultrasound measurements of bone quality in female adolescents with idiopathic scoliosis compared to normal controls

OBJECTIVE

The aims of this study were to compare the speed-of-sound (SOS) between adolescent idiopathic scoliosis (AIS) patients and controls using quantitative ultrasound examination and to further analyze the relationship between the SOS and curve type, curve magnitude, maturation status and Risser's sign in AIS patients compared to controls.

METHODS

Seventy-eight female AIS patients and 58 healthy female controls 10 to 16 years of age were recruited to participate. Quantitative ultrasound measurements were performed at the non-dominant distal end of the radius. The standard method for estimating the SOS and z-score was used. Comparisons were made between the SOS values and z-score in AIS patients and age-matched Asian adolescents.

RESULTS

The SOS values of the patients were significantly lower than the controls (P < .01). The percentage of cases with low bone quality was 25% in the entire AIS sample. The prevalence of low bone quality in AIS patients was 20.5%. However, there were no correlations between the SOS and types of scoliosis (P > .05). The SOS values among different severity groups were significant, particularly between the 10° to 19° and 20° to 39° groups as well as between 10° to 19° and ≥40° groups. However, there was no significant correlation between the SOS and Cobb angles. Significant correlations were also found between the pre- and post-menarchy status in patients. There was a significant difference in the SOS values for different Rissers' signs (P < .05).

CONCLUSIONS

Compared to nonscoliotic controls, subjects with AIS had a generally lower SOS, indicating lower bone quality. The age, Risser's sign, or maturation status, may have an effect on the bone quality; however, the curve type and magnitude do not affect the bone quality. The results of this study indicate that slower bone maturation may affect the bone quality in adolescents with AIS.

Brazilian pediatric reference data for quantitative ultrasound of phalanges according to gender, age, height and weight

Aims

To establish normative data for phalangeal quantitative ultrasound (QUS) measures in Brazilian students.

Methods

The sample was composed of 6870 students (3688 females and 3182 males), aged 6 to 17 years. The bone status parameter, Amplitude Dependent Speed of Sound (AD-SoS) was assessed by QUS of the phalanges using DBM Sonic BP (IGEA, Carpi, Italy) equipment. Skin color was obtained by self-evaluation. The LMS method was used to derive smoothed percentiles reference charts for AD-SoS according to sex, age, height and weight and to generate the L, M, and S parameters.

Results

Girls showed higher AD-SoS values than boys in the age groups 7–16 (p<0.001). There were no differences on AD-SoS Z-scores according to skin color. In both sexes, the obese group showed lower values of AD-SoS Z-scores compared with subjects classified as thin or normal weight. Age (r² = 0.48) and height (r² = 0.35) were independent predictors of AD-SoS in females and males, respectively.

Conclusion

AD-SoS values in Brazilian children and adolescents were influenced by sex, age and weight status, but not by skin color. Our normative data could be used for monitoring AD-SoS in children or adolescents aged 6–17 years.

Evidence-based outcomes on diagnostic accuracy of quantitative ultrasound for assessment of pediatric osteoporosis - a systematic review

BACKGROUND

Dual-energy absorptiometry (DXA) is the current reference standard for assessing pediatric osteoporosis; however due to its areal nature, it has limitations. Thus, quantitative ultrasound (QUS), a modality free of ionizing radiation, has been proposed as a potential surrogate for DXA.

OBJECTIVE

To semi-quantitatively assess the diagnostic accuracy of QUS for evaluating pediatric osteoporosis according to the U.S. Preventive Services Task Force guidelines.

MATERIALS AND METHODS

We retrieved articles on the diagnostic accuracy of quantitative US for assessing abnormal bone quality or quantity in patients of mean age ≤19 years from MEDLINE, EMBASE and Cochrane Library CCTR databases. Evidences were analyzed for reliability, construct and criterion validity, and responsiveness of quantitative US, according to the following questions: (1) How reliable is the acquisition of QUS measurements? (2) Is QUS diagnostically accurate to characterize bone strength and quality in osteoporotic children? (3) Is QUS sensitive to detect changes in bone status over time? (4) Is QUS able to predict future skeletal fractures/degeneration? Three reviewers independently evaluated the quality of reporting and methodological quality using the Standards for Reporting of Diagnostic Accuracy (STARD) and the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tools.

RESULTS

Out of 262 retrieved references (215 unique), we included 28 studies (1,963 patients; 807 reported boys and 761 girls, others unspecified; reported mean age, 0-19 years). The mean quality of reporting score was "excellent" in 24/28 (86%) studies; 11/28 (39%) studies had "adequate" research design quality.

CONCLUSION

There is no evidence of the diagnostic value of QUS at the present time despite the overall excellent and adequate research design quality of primary studies. Although QUS can produce reliable measurements, insufficient evidence has been reported to support other clinimetric properties of this technique.

Measurement properties of radial and tibial speed of sound for screening bone fragility in 10- to 12-year-old boys and girls

The objective of this study was to analyze measurement properties of the radial and tibial speed of sound (SoS) evaluated by quantitative ultrasound (QUS) for screening bone fragility. Bone fragility was defined as low whole body less head bone mineral density (WBLH BMD) measured by DXA (first tertile, 95% CI -1.1 to -0.9) and as past fractures evaluated by questionnaire. The sample included 319 nonobese boys and girls, ages 10-12 yr. All bone variables were standardized. The results revealed concordance coefficient correlations between WBLH BMD and radial and tibial SoS of 0.129 and 0.038, respectively. The regression lines between DXA and QUS variables were different from the identity lines. Cross-classification analysis by Kappa statistic showed that only 34% and 36% of the 113 participants categorized in the first tertile of WBLH BMD were also categorized in the first tertile of tibial and radial SoS, correspondingly. Logistic regression with gender and maturity adjustments demonstrates that radial SoS was the single significant variable in predicting OR for identifying participants with past fractures. In conclusion, the radial QUS revealed itself to be a valuable tool for screening bone fragility in youth of 10-12 yr, despite the absence of agreement with DXA WBLH BMD.

A comparative study of dual-X-ray absorptiometry and quantitative ultrasonography for the evaluating bone status in subjects with Rett syndrome

Rett syndrome, an X-linked neurodevelopmental disorder primarily affecting girls, is frequently characterized by a reduced bone mineral density (BMD) with an increased risk of fragility fractures. The aim of the study was to assess bone status by DXA technique and by quantitative ultrasound (QUS) in subjects with Rett syndrome and to evaluate which DXA or QUS parameters better correlate with clinical features. In 156 Rett subjects (mean age 13.6 ± 8.2 years) and in 62 controls, we measured BMD at femoral neck (BMD-FN) and at total femur (BMD-TF). Apparent volumetric bone mineral density (vBMAD) was also calculated. In all subjects, QUS parameters at phalanges by Bone Profiler-IGEA (amplitude-dependent speed of sound: AD-SoS and bone transmission time: BTT) were evaluated. We found that both DXA parameters and QUS parameters were significantly lower in Rett subjects than in controls. All clinical characteristics were positively correlated to BMD-FN, BMD-TF, AD-SoS, and BTT (p < 0.001) but not with vBMAD-FN. All ultrasonographic parameters were significantly correlated to BMD-FN and BMD-TF, whereas vBMAD-FN showed only positive significant correlation with densitometric parameters (p < 001). In Rett subjects BMD-FN was predicted primarily by weight and movement capacity, whereas vBMAD-FN was predicted by weight, height, and calcium intake. Moreover, AD-SoS was predicted by weight, height, and age, while BTT was predicted only by height. In conclusion, in our study the performance of QUS at phalanges was similar to those of BMD at femur, therefore, both areal BMD at femur and QUS at phalanges (AD-SoS and BTT) may be equally useful in the evaluation of skeletal status in Rett patients.

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

The International Society for Clinical Densitometry Official Revised Positions on reporting of densitometry results in children represent current expert recommendations to assist health care providers determine which skeletal sites should be measured, which, if any, adjustments should be made, reference databases to be used, and the elements to include in a dual-energy X-ray absorptiometry report. The recommended scanning sites remain the total body less head and the posterior-anterior spine. Other sites such as the proximal femur, lateral distal femur, lateral vertebral assessment, and forearm are discussed but are only recommended for specific pediatric populations. Different methods of interpreting bone density scans in children with short stature or growth delay are presented. The use of bone mineral apparent density and height-adjusted Z-scores are recommended as suitable size adjustment techniques. The validity of appropriate reference databases and technical considerations to consider when upgrading software and hardware remain unchanged. Updated reference data sets for all contemporary bone densitometers are listed. The inclusion of relevant demographic and health information, technical details of the scan, Z-scores, and the wording "low bone mass or bone density" for Z-scores less than or equal to -2.0 standard deviation are still recommended for clinical practice. The rationale and evidence for the development of the Official Positions are provided. Changes in the grading of quality of evidence, strength of recommendation, and worldwide applicability represent a change in current evidence and/or differences in opinion of the expert panelists used to validate the position statements for the 2013 Position Development Conference.

Understanding the links among neuromedin U gene, beta2-adrenoceptor gene and bone health: an observational study in European children

Neuromedin U, encoded by the NMU gene, is a hypothalamic neuropeptide that regulates both energy metabolism and bone mass. The beta-2 adrenergic receptor, encoded by the ADRB2 gene, mediates several effects of catecholamine hormones and neurotransmitters in bone. We investigated whether NMU single nucleotide polymorphisms (SNPs) and haplotypes, as well as functional ADRB2 SNPs, are associated with bone stiffness in children from the IDEFICS cohort, also evaluating whether NMU and ADRB2 interact to affect this trait. A sample of 2,274 subjects (52.5% boys, age 6.2±1.8 years) from eight European countries, having data on calcaneus bone stiffness index (SI, mean of both feet) and genotyping (NMU gene: rs6827359, rs12500837, rs9999653; ADRB2 gene: rs1042713, rs1042714), was studied. After false discovery rate adjustment, SI was significantly associated with all NMU SNPs. rs6827359 CC homozygotes showed the strongest association (recessive model, Δ = −1.8, p = 0.006). Among the five retrieved haplotypes with frequencies higher than 1% (range 2.0–43.9%), the CCT haplotype (frequency = 39.7%) was associated with lower SI values (dominant model, Δ = −1.0, p = 0.04) as compared to the most prevalent haplotype. A non-significant decrease in SI was observed in in ADRB2 rs1042713 GG homozygotes, while subjects carrying SI-lowering genotypes at both SNPs (frequency = 8.4%) showed much lower SI than non-carriers (Δ = −3.9, p<0.0001; p for interaction = 0.025). The association was more evident in preschool girls, in whom SI showed a curvilinear trend across ages. In subgroup analyses, rs9999653 CC NMU or both GG ADRB2 genotypes were associated with either lower serum calcium or β-CrossLaps levels (p = 0.01). This study in European children shows, for the first time in humans, a role for NMU gene through interaction with ADRB2 gene in bone strength regulation, more evident in preschool girls.

Normative data for quantitative calcaneal ultrasonometry in Turkish children aged 6 to 14 years: relationship of the stiffness index with age, pubertal stage, physical characteristics, and lifestyle

OBJECTIVES

Quantitative ultrasonometry is commonly used to assess bone health. The aim of this study was to define normative data for the stiffness index of the calcaneus in healthy Turkish children.

METHODS

Quantitative ultrasonometric measurements of the calcaneus were obtained in 1617 healthy schoolchildren (811 boys and 806 girls) aged 6 to 14 years.

RESULTS

The stiffness index increased by 19.3% and 12% in boys and girls, respectively. The greatest increases were seen in the age groups of 12 to 13 and 13 to 14 years in boys (3.9%) and 11 to 12 and 12 to 13 years in girls (4.1%). There was a significant increase in stiffness index values among all Tanner stages except stage 4 (P < .05). Although the stiffness index was related to age, weight, and height, no correlation was seen between the stiffness index and calcium intake or physical activity.

CONCLUSIONS

This study provides stiffness index data by age group and Tanner stage that may be useful for assessment of the bone status of Turkish children and can serve as comparative data for other patient groups.

Relationship between markers of body fat and calcaneal bone stiffness differs between preschool and primary school children: results from the IDEFICS baseline survey

The aim of this study was to investigate the relationship between markers of body fat and bone status assessed as calcaneal bone stiffness in a large sample of European healthy pre- and primary school children. Participants were 7,447 children from the IDEFICS study (spread over eight different European countries), age 6.1 ± 1.8 years (range 2.1-9.9), 50.5 % boys. Anthropometric measurements (weight, height, bioelectrical impedance, waist and hip circumference, and tricipital and subscapular skinfold thickness) as well as quantitative ultrasonographic measurements to determine calcaneal stiffness index (SI) were performed. Partial correlation analysis, linear regression analysis, and ANCOVA were stratified by sex and age group: preschool boys (n = 1,699) and girls (n = 1,599) and primary school boys (n = 2,062) and girls (n = 2,087). In the overall study population, the average calcaneal SI was equal to 80.2 ± 14.0, ranging 42.4-153. The results showed that preschool children with higher body fat had lower calcaneal SI (significant correlation coefficients between -0.05 and -0.20), while primary school children with higher body fat had higher calcaneal SI (significant correlation coefficients between 0.05 and 0.13). After adjusting for fat-free mass, both preschool and primary school children showed an inverse relationship between body fat and calcaneal stiffness. To conclude, body fat is negatively associated with calcaneal bone stiffness in children after adjustment for fat-free mass. Fat-free mass may confound the association in primary school children but not in preschool children. Muscle mass may therefore be an important determinant of bone stiffness.

Longitudinal changes in calcaneal quantitative ultrasound measures during childhood

This longitudinal study examined how calcaneal quantitative ultrasound (QUS) measures change during childhood while taking into account skeletal maturation, body mass index (BMI), and physical activity. The study reported sex differences in QUS growth curves and an inverse relationship between BMI and speed of sound (SOS) measures.

INTRODUCTION

The aim of this study was to examine how calcaneal QUS parameters change over time during childhood and to determine what factors influence these changes.

METHODS

The study sample consisted of a total of 192 Caucasian children participating in the Fels Longitudinal Study. A total of 548 calcaneal broadband ultrasound attenuation (BUA) and SOS observations were obtained between the ages of 7.6 and 18 years. The best fitting growth curves were determined using statistical methods for linear mixed effect models.

RESULTS

There are significant sex differences in the pattern of change in QUS parameters (p < 0.05). The relationship between QUS measures and skeletal age is best described by a cubic growth curve in boys and a linear pattern among girls. Boys experience their most rapid growth in BUA and SOS in early and late adolescence, while girls experience constant growth throughout childhood. Adiposity levels were significantly associated with the changes in SOS among boys (p < 0.001) and girls (p < 0.01), indicating that children with higher BMI are likely to have lower SOS over time compared to children with lower BMI. For girls, physical activity levels showed positive associations with changes in QUS measures (p < 0.05).

CONCLUSION

This study documents significant sex differences in the pattern of change in QUS measures over childhood and adolescence. Our study also shows significant influences of adiposity and physical activity on the pattern of change in QUS measures during childhood.

Normative Data for Quantitative Calcaneal Ultrasound in Asian Children

Introduction: Dual energy X-ray absorptiometry (DEXA) is currently the gold standard for the assessment of bone mineral density. Quantitative ultrasound (QUS), on the other hand, is a radiation-free alternative for the assessment of bone strength in the paediatric population. Establishing normative data for bone strength specific to the population would allow identification of children at risk of osteoporosis as a consequence of disease and its treatment. This cross-sectional study aims to establish the normal reference range for calcaneal broadband ultrasound attenuation (BUA) measurements in normal Singaporean children aged 6 to 12 years. Materials and Methods: Healthy Singaporean children were randomly selected from 11 primary schools for the assessment of calcaneal BUA, using the paediatric Contact Ultrasonic Bone Analyzer (CUBA, McCue Plc, Compton, Winchester, England). The height, weight, body mass index and BUA measurements for each age group and gender were expressed as the mean ± SD. One-way ANOVA was used to compare the mean calcaneal BUA by age and gender of Singaporean children with that of children from the United Kingdom, Turkey and Taiwan. Results: A total of 750 healthy Singaporean children (417 males and 333 females) aged 6 to 12 years from 11 primary schools were enrolled. The calcaneal BUA values of Turkish and white British children were not statistically different from this Singaporean cohort. However, the Singaporean calcaneal BUA measurements were significantly higher compared to the Taiwanese children. Conclusion: This study provides the first normal reference data to evaluate bone strength in Singaporean children using the paediatric Contact Ultrasonic Bone Analyzer. Keywords: Bone strength, Osteoporosis, Paediatrics

Normative calcaneal quantitative ultrasound data as an estimation of skeletal development in Swedish children and adolescents

We present age- and gender-specific normative bone status data evaluated by quantitative ultrasound (QUS) in the calcaneus with the Lunar Achilles device and compare these estimates with bone mineral content (BMC) and bone mineral density (BMD) estimated by dual X-ray absorptiometry (DXA). Included were a sample of 518 population-based collected Swedish girls and 558 boys aged 6-19 years. QUS measurements included speed of sound (SOS), broadband ultrasound attenuation (BUA), and stiffness index (SI) in the calcaneus. DXA measurements included BMC and BMD in the femoral neck (FN), lumbar spine (L2-L4), and total body (TB). Height and weight were measured with standard equipment. Age, height, and weight were significantly associated with SOS, BUA, and SI. Compared to SOS, in both girls and boys there was a higher correlation between BUA and FN BMC (r = 0.71 and r = 0.73, respectively), FN BMD (r = 0.68 and r = 0.67, respectively), L2-L4 BMC (r = 0.70 and r = 0.64, respectively), L2-L4 BMD (r = 0.69 and r = 0.64, respectively), TB BMC (r = 0.76 and r = 0.75, respectively), and TB BMD (r = 0.74 and r = 0.74, respectively). The correlations between SOS and FN BMC (r = 0.38 and r = 0.52, respectively), FN BMD (r = 0.41 and r = 0.52, respectively), L2-L4 BMC (r = 0.31 and r = 0.40, respectively), L2-L4 BMD (r = 0.32 and r = 0.41, respectively), TB BMC (r = 0.42 and r = 0.49, respectively), and TB BMD (r = 0.48 and r = 0.54, respectively) were lower, although still significant (all P < 0.001). BUA seems to be the QUS parameter that best resembles the changes in BMC during growth.

Bone status in adolescents with type 1 diabetes

AIMS

The aim of the study was to investigate the potential negative impact of type 1 diabetes on bone status of adolescents. Bone status in adolescents with type 1 diabetes was assessed by means of quantitative ultrasound (QUS) and the influence of metabolic control and other disease-related and growth variables was analysed.

METHODS

Group I consisted of 99 pubertal (Tanner > or = 2) adolescents (49 female), aged 14.3 +/- 2.5 years, diabetes duration 4.6 +/- 2.3 years. Controls (group II) were 297 children, matched by sex and age, from a healthy population. The influence of glycated haemoglobin (current: HbA(1c)D; last year's mean: HbA(1c)Y; whole duration mean: HbA(1c)T), diabetes duration, percentage of life with disease and daily insulin requirement (DIR) on amplitude dependent speed of sound (Ad-SoS) at distal phalanges was studied.

RESULTS

In comparison to the control group, adolescents with type 1 diabetes presented significantly higher BMI SDS (0.82 [95% CI 0.54, 1.10] vs -0.06 [95% CI -0.16, 0.04] p < 0.001) and lower Ad-SoS SDS (-0.34 [95% CI -0.57, -0.11] vs -0.03 [95% CI -0.15, 0.08], p < 0.05). No correlation between Ad-SoS SDS and sex, DIR or diabetes duration was observed. The lower Ad-SoS SDS reflects reduced bone status, and the reduction was significantly more marked in those patients whose HbA(1c)T was higher than 7.0% when compared with those whose HbA(1c)T was lower.

CONCLUSIONS

Bone status of adolescents with type 1 diabetes mellitus assessed with QUS differs from that of healthy peers and is dependent on long-term metabolic control.

Quantitative ultrasound and dual-energy x-ray absorptiometry in children and adolescents with neurofibromatosis of type 1

Reduced areal bone mineral density (aBMD) is a common feature of neurofibromatosis type 1 (NF1). Moreover, in recent years there has been a growing interest in using quantitative ultrasound (QUS) for the evaluation of bone status. In 55 NF1 subjects (mean age: 9.3+/-5.4yr) and in 51 age- and sex-matched controls we measured aBMD at lumbar spine, at femoral neck (aBMD-FN), and at total femur (aBMD-T). Apparent volumetric bone mineral density (BMAD) was also calculated. In all subjects, QUS parameters at phalanges were evaluated. In NF1 subjects, the values of aBMD and BMAD were lower than in controls at all skeletal sites, but the difference reached statistical significance only at femoral sites (p<0.05). Both aBMD and QUS parameters were lower in those NF1 subjects with skeletal abnormalities than in those without abnormalities, but the difference was statistically significant (p<0.05) only for aBMD-FN and aBMD-T. Multiple regression analysis showed that the subjects with skeletal abnormalities had a higher risk of having bone transmission time (BTT) Z-score and aBMD Z-score at femoral sites less than -1. In conclusion, our results suggest that aBMD and QUS represent useful tools in evaluating the impairment of bone status in NF1 subjects.

Analysis of quantitative ultrasound graphic trace and derived variables assessed at proximal phalanges of the hand in healthy subjects and in patients with cerebral palsy or juvenile idiopathic arthritis. A pilot study

Amplitude-dependent speed of sound (AD-SoS) and bone transmission time (BTT) are the quantitative ultrasound (QUS) variables usually assessed at proximal phalanges of the hand to estimate bone mineral status. The aim of the study was to provide a reference database for some additional QUS variables reflecting morphology of the ultrasound graphic trace according to gender, age, height, weight, and body mass index (BMI), and to assess their clinical usefulness. Fifty-two patients (age 3.1-20.9 years) affected by cerebral palsy with spastic tetraplegia (CPST, n=38) or polyarticular active juvenile idiopathic arthritis (JIA, n=14) were examined. In addition to AD-SoS and BTT, two QUS variables derived from the morphological analysis of ultrasound graphic trace, such as energy, extrapolated from the area under the ultrasound signal received, and weighted-slope (W-slope), derived from the angular coefficient of the regression line fitting the top point of the peaks of the ultrasound signal, were measured by phalangeal QUS (DBM Sonic, IGEA). The values of all the QUS variables measured in the patients were compared with our own sex- and age-reference values (n=1083, 587 males and 496 females, aged 3-21 years). The mean values of AD-SoS, BTT, energy, and W-slope were reduced (P<0.0001) in patients as a whole compared with normative data (-2.4+/-1.2, -2.7+/-1.5, -2.5+/-1.1, -2.5+/-1.1 Z-score, respectively). Fractured patients showed lower (P<0.001-P<0.0001) values of the QUS variables than fracture-free patients (AD-SoS, -3.3+/-1.2 and -1.8+/-0.9; BTT, -3.9+/-1.7 and -1.8+/-1.1; energy, -3.2+/-1.2 and -2.2+/-0.7; W-slope, -3.4+/-1.4 and -2.2+/-0.9 Z-score, respectively). There was no difference (P=NS) between patients with CPST and those with JIA. Age and height were positively correlated with all the QUS variables (r=0.55-0.79, P<0.01-P<0.0001). QUS variables were positively correlated among them (r=0.74-0.94, P<0.0001). Age and number of fractures were independent predictors of the QUS variables (coefficients: AD-SoS, 11.466 and -17.642; BTT, 0.049 and -0.045; energy, 1.072 and -1.303; W-slope, 0.046 and -0.067; respectively). In conclusion, measurement of QUS variables derived from the morphological analysis of the ultrasound signal could give additional information in estimating bone mineral status in children and adolescents, probably reflecting some aspect related to bone structure.

Reference values for quantitative ultrasonography (QUS) of radius and tibia in healthy greek pediatric population: clinical correlations

The aim of this study was to provide reference standards for measurements of quantitative ultrasonography (QUS) of radius and tibia in normative Greek pediatric population. Analysis was performed in 1549 healthy subjects (814 girls and 735 boys) with a mean decimal age of 11.41+/-3.52 yr (range: 3.78-18.33 yr). Results showed a gradual increase of absolute values of radial and tibial speed of sound (SOS), with aging and with pubertal progressing, in both girls and boys. Gender comparison showed significantly increased SOS values measured both at radius and at tibia in girls more than 13 yr of age compared with aged-matched boys. Significant but mild correlation was noted between standard deviation scores (SDS) of SOS at radius and at tibia (r = 0.259, p < 0.001). Additionally, tibial SOS SDS were significantly negatively correlated with body mass index (BMI) SDS (r = -0.230, p < 0.001). Finally, subjects that spend more than 3h of daily "screen time" (television and personal computer) showed significantly decreased SOS values measured both at radius and at tibia. On the contrary, no correlation was observed between SOS values and the amount of physical activity reported.

Quantitative ultrasound in the assessment of skeletal status

Quantitative ultrasound (QUS) is a non-invasive technique for the investigation of bone tissue in several pathologies and clinical conditions, especially in the field of osteoporosis. The versatility of the technique, its low cost and lack of ionising radiation have led to the diffusion of this method worldwide. Several studies have been conducted in the last years to investigate the potential of QUS in multiple areas with promising results; the technique has been applied in the prediction of osteoporotic fractures, in monitoring therapies, in the investigation of secondary osteoporosis, in paediatrics, neonatology and genetics. Our review article gives an overview of the most relevant developments in the field of quantitative ultrasound, both in clinical and in experimental settings.

Evaluation of bone turnover in epileptic children using oxcarbazepine

This study evaluated the effects of oxcarbazepine monotherapy on bone turnover in prepubertal and pubertal children. Thirty-four newly diagnosed pediatric patients with normal bone mineral density, serum biochemical markers of bone formation, and hormonal markers participated. Levels of 25-hydroxyvitamin D were significantly decreased after therapy compared with baseline values. Levels of gamma-glutamyl transferase, phosphorus, alkaline phosphatase, osteocalcin, parathyroid hormone, and calcitonin had increased. However, only changes in osteocalcin and gamma-glutamyl transferase levels were statistically significant compared with baseline values. Drug-induced osteopenia was evident in 3 patients with z scores of bone-mineral density less than -2.0, whereas these patients had z scores of less than -1.5 before treatment. Although 18 months of oxcarbazepine treatment exerted slightly adverse effects on bone metabolism, the effect seems insignificant in children with normal bone-mineral density. Although alterations in bone metabolism do not always suffice to explain the decrease in bone-mineral metabolism, we think that patients with osteopenia before the initiation of oxcarbazepine therapy should be followed carefully, especially in long-term treatment.

Dual energy X-ray absorptiometry interpretation and reporting in children and adolescents: the 2007 ISCD Pediatric Official Positions

The International Society for Clinical Densitometry Official Positions on reporting of densitometry results in children represent an effort to consolidate opinions to assist healthcare providers determine which skeletal sites should be assessed, which adjustments should be made in these assessments, appropriate pediatric reference databases, and elements to include in a dual energy X-ray absorptiometry (DXA) report. Skeletal sites recommended for assessment are the lumbar spine and total body less head, the latter being valuable as it provides information on soft tissue, as well as bone. Interpretation of DXA findings in children with growth or maturational delay requires special consideration; adjustments are required to prevent erroneous interpretation. Normative databases used as a reference should be based on a large sample of healthy children that characterizes the variability in bone measures relative to gender, age, and race/ethnicity, and should be specific for each manufacturer and model of densitometer and software. Pediatric DXA reports should provide relevant demographic and health information, technical details of the scan, Z-scores, and should not include T-scores. The rationale and evidence for development of the Official Positions are provided. Given the sparse data currently available in many of these areas, it is likely that these positions will change over time as new data become available.

Methods for measurement of pediatric bone

Many experts believe that optimizing bone mineral accrual early in life may prevent childhood fractures and possibly delay the development of osteoporosis later in life. Adequate nutrition and physical activity are environmental factors important in determining whether or not children acquire an appropriate amount of bone for their body size. Pediatric diseases, or therapeutic interventions used in their treatment, may interfere with normal bone development. Although there are specific methods available for assessing pediatric bone, there is no one method that can adequately assess bone health and identify the specific bone deficits that may be occurring. Understanding the biological basis for bone deficits and the ability of various bone assessment methods to discriminate or measure these deficits is important in understanding normal bone development and how to prevent and treat pediatric bone disease. The purpose of this review is to briefly describe changes in bone with growth, to define "bone density" in biological terms, to discuss some of the issues with pediatric bone measurements, and to review the three main methods for assessing bone parameters in pediatric populations. These methods, including dual energy X-ray absorptiometry (DXA), quantitative ultrasound (QUS) and peripheral quantitative computed tomography (pQCT) will be described, the advantages and disadvantages discussed, and the relationship between bone parameters and fracture risk presented for each of the methods.

Quantitative ultrasound methods to assess bone mineral status in children: technical characteristics, performance, and clinical application

Measurement of bone mineral status may be a useful tool in identifying the children who could be exposed to an increased risk of osteoporosis in adulthood. Dual energy x-ray absorptiometry and peripheral quantitative computed tomography may be used to this purpose, but the exposure to ionizing radiation is a limiting factor for preventive studies in large populations of children. In the last years, quantitative ultrasound (QUS) methods have been developed to assess bone mineral status in some peripheral skeletal sites such as calcaneus, phalanges of the hand, and tibia. QUS techniques are safe, easy to use, radiation-free, and devices are portable, so that they are particularly indicated to assess bone mineral status in children. This review will concentrate on the main methodological principles of ultrasounds and the QUS variables derived from their application to bone tissue, technical differences and performance of QUS methods, factors influencing QUS measurements, normative data and results obtained in children with disturbances of growth or affected by disorders of bone and mineral metabolism, including the assessment of fracture risk, and comparison among QUS, dual energy x-ray absorptiometry, and peripheral quantitative computed tomography methods.

Current concepts in bone and reproductive health in adolescents with anorexia nervosa

Anorexia nervosa (AN) initiates an adaptive response at the level of the hypothalamus, which results in a complex interplay involving most elements of the neuroendocrine axis. Consequences of onset of disease in adolescence include amenorrhoea, pubertal arrest with potential loss of target height, and osteoporosis with reduced capacity for future attainment of peak bone mass. With recovery, delay in restoration of menses is common. Hormonal therapies for restoration of bone mineral density (BMD) in adolescents have shown limited efficacy. This review will discuss the reproductive endocrine effects of AN in adolescence, and discuss new investigative tools for monitoring restoration of reproductive function and BMD in this population.

Which bone mass measures discriminate adolescents who have fractured from those who have not?

This study of 415 adolescent children examined the association between four different measures of bone mass and prevalent fracture (N = 160 children). DXA measures and calcaneal ultrasound (but not radial ultrasound or metacarpal index) were associated with upper limb fracture, suggesting heel ultrasound is also a discriminator of fractures in children.

INTRODUCTION

The aim of the study was to describe the association between different measures of bone mass and prevalent fracture in adolescents.

METHODS

A total of 415 adolescents (150 girls and 265 boys), mean age 16.3 years were examined. Dual energy X-ray absorptiometry (DXA) measures were performed at hip, spine, radius and total body. Calcaneal bone ultrasound attenuation (BUA), speed of sound (SOS), and stiffness were assessed by a Sahara densitometer. Radial ultrasound SOS was assessed by a Sunlight 8000P machine. Metacarpal index was calculated from a left hand X-ray. Prevalent fractures were assessed by questionnaire.

RESULTS

A total of 160 adolescents (39%) reported at least one previous fracture (106 upper limb, 53 lower limb, one other for first fracture). Significantly lower DXA measures, heel BUA, and heel stiffness was observed in those with a history of upper limb fracture (all P < 0.05). Despite significant correlations between all the bone mass measures, radial ultrasound and metacarpal index did not discriminate those with fracture from those without. Similar associations were present for number of fractures. No bone measure was able to discriminate lower limb fracture.

CONCLUSIONS

Both calcaneal quantitative ultrasound and DXA are able to discriminate adolescents with a history of upper limb fracture from those without.

Precision of Lunar Achilles+ bone quality measurements: time dependency and multiple machine use in field studies

Qualitative ultrasound (QUS) is a portable, safe and relatively inexpensive technique used to obtain information on bone mineral quality in adults and children. QUS measures bone stiffness index (SI) through the incorporation of speed of sound (SOS) and broadband ultrasound attenuation (BUA). QUS technology may prove to be extremely useful in field research where more than one machine is used over different periods of time. 13 adults (27.6+/-4.6 years old) were recruited to determine the internal stability of two Lunar Achilles+ QUS machines (Lunar1, Lunar2), as well as the repeatability in bone stiffness measures between the two machines over time. Triplicate measurements of the calcaneus were taken within the same day (n = 258) and at 1 week (n = 120), 6 months (n = 54) and 1 year (n = 18) apart to determine the time-dependent repeatability. Using paired t-tests and separate mixed effects models, there were no differences reported in SI, SOS or BUA values within one machine, or between two machines over these short- and long-term time-frames. These results indicate that QUS machines are internally consistent and different machines may be used over time to provide reliable measurements of changes in bone quality.

Modifiable lifestyle factors affecting bone health using calcaneus quantitative ultrasound in adolescent girls

One hundred and fourteen girls were measured for calcaneus QUS (stiffness index score), calcium intake, weight, and total hours spent in physical activity (moderate to high-impact activities and low to no-impact activities). Multiple regression analysis indicated that hours spent in moderate to high-impact activities, current calcium intake, and weight significantly predicted SI.

INTRODUCTION

To determine the influence of modifiable lifestyle factors on adolescent girls' bone health measured by calcaneus quantitative ultrasound (QUS).

METHODS

One hundred and fourteen girls, ages 14-18 (15.97 +/- .7), enrolled in high school physical education classes, were measured for calcaneus QUS (stiffness index score), height, weight, current calcium intake from 2-3 day food records, and estimated total hours spent in physical activity from kindergarten to present. Cumulative physical activity hours were separated into two classifications (according to their estimated strain from ground reaction force): moderate to high-impact activities and low to no-impact activities.

RESULTS

Pearson correlations between stiffness index (SI) and age, height, weight, current calcium intake, and hours spent in moderate to high-impact versus low to no-impact activities indicated a positive relationships between SI and weight (r = .259, p = .005), current calcium intake (r = .286, p = .002), and hours spent in moderate to high-impact activities (r = .451, p < .001). Multiple regression between SI and the above independent variables indicated that collectively, hours spent in moderate to high-impact activities, current calcium intake, and weight (r (2) = .363, p = <.001) significantly predicted SI.

CONCLUSION

Our data indicate that moderate to high-impact activities, current calcium intake, and weight positively influence bone properties of the calcaneus in adolescent girls.

Skeletal measurements by quantitative ultrasound in adolescents and young women with anorexia nervosa

OBJECTIVE

To compare quantitative ultrasound (QUS) measurements in adolescents with anorexia nervosa (AN) with that in healthy control subjects and to determine the utility of QUS as a tool to evaluate skeletal status in these patients.

STUDY DESIGN

Female adolescents with AN (n = 41) and healthy control subjects (n = 105) were recruited. Speed of sound (SOS) was measured at the radius and tibia. Participants with AN also had hip and spinal areal bone mineral density measurements by dual-energy x-ray absorptiometry (DXA); bone mineral apparent density (BMAD) was calculated.

RESULTS

Subjects with AN had higher mean radial SOS (4044 +/- 99 m/s) than did control subjects (3947 +/- 116 m/s; P < .0001). These results were replicated at the tibia (AN, 3918 +/- 85 m/s vs control subjects, 3827 +/- 106 m/s; P < .0001). Neither DXA measures of areal bone mineral density nor BMAD were correlated with SOS. Weight and body mass index were negative predictors of tibial but not radial SOS. AN status remained a significant predictor of SOS after controlling for body mass index, age, and race.

CONCLUSIONS

Subjects with AN had higher mean tibial and radial SOS than did control subjects. QUS variables did not correlate with DXA measures, calculated BMAD, or anthropometric variables. QUS measurements of SOS do not appear to be appropriate for bone density screening in patients with AN.

Quantitative ultrasound variables of the heel in Finnish men aged 18-20 yr: predictors, relationship to bone mineral content, and changes during military service

INTRODUCTION

Determinants of BUA and SOS and their changes during military service-associated physical training were studied in 196 army recruits and 50 control men, aged 18-20 years.

METHODS

Heel ultrasound measurement, DXA, muscle strength test, Cooper's running test and genetic analyses were performed. Lifestyle factors were recorded. Sex steroids and bone turnover markers were determined. Heel ultrasound was repeated after six months.

RESULTS

Exercise was the most significant determinant of both BUA (p<0.0001) and SOS (p<0.0001). There were 10% and 1.3% differences in BUA (p=0.006) and SOS (p=0.0001), respectively, between men belonging to the lowest and highest quartiles of exercise index. Weight associated with BUA (p=0.005) and height with SOS (p=0.03). BUA and SOS correlated with BMC and BMD (p<0.0001) but explained only up to 21% of their variance. Over six months SOS increased more in recruits than in control men (p=0.0043), the increase being higher, the lower muscle strength at baseline (r =-0.27, p=0.0028).

CONCLUSION

Exercise is the most important determinant of ultrasonographic variables in men, aged 18-20 years. Physical loading during military training increases SOS.

Assessing bone mass in children and adolescents

Growing awareness that osteoporosis may have its antecedents in childhood has led to increasing interest in assessing bone mass in children and adolescents. Several noninvasive imaging techniques are currently available to measure properties of the growing skeleton, including bone mass, density, cross-sectional area, and microarchitecture. Dual-energy x-ray absorptiometry (DXA) is the most widely used technique, but it has several major limitations associated with its dependence on two-dimensional projections. Quantitative CT and peripheral quantitative CT allow three-dimensional imaging but are more costly and have higher radiation exposure. Quantitative ultrasound is simple and inexpensive but can measure bone "quality" only at a single peripheral site. MRI techniques for measuring bone are still under development and not yet ready for clinical use. For all of these techniques, clinical interpretation of the bone measures obtained remains a significant challenge. Further research is needed to relate these measures to osteoporosis in the elderly and to short-term and long-term fracture risk.

QCT versus DXA in 320 survivors of childhood cancer: association of BMD with fracture history

PURPOSE

To assess agreement on diagnosis of diminished bone mineral density (BMD) and correlation between BMD values obtained by dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT) in childhood cancer survivors.

PATIENTS AND METHODS

We retrospectively reviewed lumbar spine QCT and DXA studies for BMD in patients who underwent both imaging studies within a 24-hr period. We determined correlation between BMD values and agreement on diagnosis of diminished BMD obtained by both modalities. Diminished BMD was defined as two or more SDs below mean for age- and gender-matched reference values. We evaluated the relationship of BMD values determined by each modality to self-reported fracture history in the 160 (50%) patients with available reports.

RESULTS

Of 320 patients, 56% (178) were male; 87% (277) were white. Median age was 16.4 (range, 5.1-36.0) years. Median BMD Z-score was -1.43 (range, -5.96 to 3.20) by QCT and -1.30 (range, -5.50 to 2.80) by DXA. Correlation between QCT- and DXA-determined BMD values was significant but low, and agreement on diminished BMD was fair (kappa = 0.32). There was no association between BMD measured by either QCT or DXA and self-reported traumatic fracture history. Male gender was associated with doubling the traumatic fracture risk (P = 0.0499).

CONCLUSIONS

Quantitative computed tomography and DXA may give discrepant results when used to assess bone health in childhood cancer survivors, especially in those of non-white race. This inconsistency in indicators of BMD deficiency may complicate clinical decision-making. Consecutive use of a single modality is recommended to provide reliable longitudinal information.

Effects of nutrition, puberty, and gender on bone ultrasound measurements in adolescents and young adults

PURPOSE

Quantitative ultrasound (QUS) evaluation of bone is attractive for evaluating skeletal status in adolescents, but its use is limited in the United States due to sparse pediatric reference data. This study evaluated associations between radial and tibial speed of sound (SOS) measurements via QUS and demographic, anthropometric and nutritional variables.

METHODS

We enrolled 151 healthy participants, aged 11-26 years, during routine visits to an urban adolescent clinic. SOS measurements were obtained using the Omnisense 7000P (Sunlight Medical Ltd., Tel-Aviv, Israel) and correlated with weight, height, gender, race, sexual maturity rating (SMR), and reported nutritional intake.

RESULTS

The sample was 53% female; aged 17+/- 2.8 years (mean +/- SD); and 48% African-American, 21% Hispanic, and 21% Caucasian. Seventy percent of males and 91% of females had achieved SMR 5; 96% of females were postmenarchal. Males met the recommended daily allowance for calcium intake, on average; the females did not. Both the girls and boys reported consumption of inadequate vitamin D. Intake of neither calcium nor vitamin D was correlated with SOS. Radial and tibial SOS were significantly higher in those with SMR 5 (p < .001) and were moderately correlated with age in both genders (r = .42-.64, p < .001). In multivariate analyses, age was associated with SOS at both sites (p < .0001).

CONCLUSIONS

This study provides QUS measurements of the peripheral skeleton among healthy adolescents. QUS measurements followed similar age and pubertal distributions to dual-energy X-ray absorptiometry (DXA) bone density measurements; other variables did not follow expected trends. Further research is needed to clarify what skeletal properties are assessed by this technique. This study adds to accumulating evidence that many adolescents do not consume adequate vitamin D or calcium.

A pilot study of heel ultrasound to screen for low bone mass in children with leukemia

The optimal method to assess pediatric bone mass remains controversial. Dual x-ray absorptiometry (DXA) is commonly used but quantitative ultrasound is less expensive, free of ionizing radiation, and predicts fractures as well as DXA does, in adults. Broadband ultrasound attenuation (BUA) was determined using a portable calcaneal ultrasonometer and, compared with DXA derived areal bone mineral density (BMD) values in 42 young patients (ages 4.5 to 20.3 y) with leukemia. Reduced BMD was defined as a DXA z score of <-1. Mean z scores for lumbar spine BMD were significantly lower than zero (-0.77+/-1.23 SD, P=0.0004). Mean z scores for whole body BMD were also significantly lower than different from 0 (-0.34+/-1.04 SD, P=0.05). Calcaneal BUA was highly correlated with DXA measurement of lumbar, whole body, and femoral neck BMD. BUA was significantly associated with the probability of having a reduced lumbar BMD z score (P=0.03) and having a reduced whole body z score of (P=0.03). Area under the receiver operator characteristic curves for model including BUA predicting reduced bone density by DXA were 0.77 and 0.86 for lumbar and whole body z score cutoffs, respectively. Our data suggest that calcaneal BUA may serve as a reliable screening tool to detect reduced bone mass in pediatric patients with leukemia.

Comparison of phalangeal ultrasound and dual energy X-ray absorptiometry in healthy male and female adolescents

The aims of this study were to determine if there is a correlation between dual energy X-ray absorptiometry (DXA) and phalangeal quantitative ultrasound (QUS) in identifying children and adolescents with low bone density, and to assess if body size influences the results of the two techniques to the same degree. Measurements were performed in 67 girls and 83 boys aged 14 to 19 y using DBM Sonic 1200 (IGEA, Carpi, Italy) and the DXA equipment (LUNAR Radiation Corp., Madison, WI, USA). Twelve adolescents (eight males and four females) reported a past history of nonosteoporotic fractures. Lumbar spine bone mineral density (LS BMD), total body bone mineral density (TB BMD) and total body bone mineral content (TB BMC) correlated positively with age, height, BMI and weight, in both genders. Amplitude-dependent speed of sound (Ad-SOS) was positively correlated with age, height and Tanner stages in both genders and negatively correlated with BMI in females. TB BMD, TB BMC and LS BMD positively correlated with Ad-SOS only in males. In females, there were no significant correlations between Ad-SOS, TB BMD, TB BMC and LS BMD measurements. Twelve teenagers with previous fractures (high impact fractures) were found to have lower DXA and QUS values than age-matched teenagers without fractures but the statistical significance was found only in relation to TB BMD values (p = 0.02). In conclusion, we obtained results similar to those that have been reported by other authors using different QUS techniques. Furthermore, the Ad-SOS measurements taken at the distal metaphysis of the proximal phalanges correlate poorly with LS BMD and TB BMD measured by DXA in growing subjects.

Osteoporosis and measurement of bone mass in children and adolescents

Osteoporosis increasingly is recognized as a pediatric concern. Fragility fractures occur in children and adolescents with genetic disorders and those with a variety of chronic diseases. Others may not fracture in childhood but reach adulthood with a reduced peak bone mass and increased lifelong risk of osteoporosis. This article reviews the indications for pediatric bone density testing, the strengths and limitations of densitometry methods, and the challenges of interpreting the results. The goals are to demystify the densitometry report and to clarify the role of bone density tests in assessing and managing skeletal health in children.

Dual-Energy X-Ray Absorptiometry Analysis of Implants in Rat Tibiae

Dual energy x-ray absorptiometry (DXA) was evaluated for its ability to measure changes in bone mineral density in isolated rat tibiae. This technique is available for in vivo use to potentially augment or replace some aspects of conventional histomorphometric techniques used for the evaluation of metallic implant-to-bone interfaces. Known quantities of hydroxyapatite powder, representing various bone densities, were measured using DXA in a series of 3 experiments: (1) the hydroxyapatite powder was placed within a plastic tube, (2) the hydroxyapatite was placed within an excised rat tibia, and (3) hydroxyapatite powder was placed within a rat tibia with soft tissue overlying it. Statistical analysis (analysis of variance) showed significant differences in bone mineral density among groups that varied by only 5% hydroxyapatite density within the plastic tubes. The system detected hydroxyapatite changes of 20% within the tibiae with and without overlying soft tissue (P < 0.05). These data were consistent and linear (R > 0.90). Although DXA analysis has been widely used in clinical and research applications for detection of osteoporosis, its use for documenting bone growth around implants has not been widely reported. The use of such a technique could have substantial benefits for both the clinical and research arenas. These data show that DXA analysis to identify bone density changes adjacent to implants has significant applications in small animal research models.

Bone mineral metabolism changes in epileptic children receiving valproic acid

OBJECTIVE

The aim of this study was to evaluate bone mineral density (BMD) in epileptic children receiving valproic acid (VPA) and to determine differences between osteopenic and non-osteopenic children.

METHODS

Thirty-three epileptic children, receiving VPA for at least 6 months, were compared with 33 healthy children for BMD. BMD was measured by dual-energy X-ray absorptiometry at lumbar vertebrae, femoral neck and greater trochanter. Serum calcium, phosphorus, alkaline phosphates, osteocalcin and VPA levels were also determined.

RESULTS

Patient's osteocalcin levels were significantly higher (P = 0.02) and femur and trochanter BMD values were significantly lower (P = 0.04 and P = 0.03, respectively). Duration of VPA therapy was significantly longer and doses of VPA were significantly higher in seven osteopenic patients compared with 26 non-osteopenic patients. Osteopenic patients (4.6 +/- 2.4 years) were younger than non-osteopenic patients (7.8 +/- 3.2 years) (P = 0.01).

CONCLUSION

Long-term and high dose VPA therapy may cause osteopenia, primarily in younger epileptic children. These patients should be followed closely by BMD measurements.