Tibial quantitative ultrasound versus whole-body and lumbar spine DXA in a Dutch pediatric and adolescent population

Comparison of quantitative ultrasonography and dual X-ray absorptiometry for bone status assessment in South African children living with HIV

Children living with HIV (CLHIV) have decreased bone mineral content (BMC) and density (BMD), increasing risk for fracture and future osteoporosis. While DXA is the gold-standard for bone assessments, it lacks availability in resource-constrained settings (RCS). Quantitative ultrasound (QUS) offers an alternative owing to its portability, low cost, ease of handling, and lack of ionizing radiation. While QUS has detected reduced bone quality in CLHIV, the relationship between QUS and DXA in this population remains unexplored. At baseline and 12 months, BMC and BMD of the whole body, lumbar spine, and radius were measured by DXA in a longitudinal cohort of CLHIV in Johannesburg, South Africa. Calcaneal speed of sound (SOS) and broadband ultrasound attenuation (BUA) and radius SOS were obtained by QUS, and calcaneal stiffness index (SI) was calculated. Spearman correlations, with and without HIV stratification, were performed between QUS and DXA measurements at each visit and for absolute difference in measurements between visits. At baseline and 12-months, calcaneal BUA and SI displayed strong positive correlations with DXA, with only modest correlations between radial QUS and DXA at baseline. Longitudinal measures of QUS did not correlate with DXA. At both baseline and 12-months, individuals with DXA whole-body BMD z-score < -1 displayed significantly lower calcaneal BUA and SI. Cross-sectionally, calcaneal QUS correlates strongly with whole body DXA and may represent a viable diagnostic alternative in RCS. Longitudinally, the two methods do not correlate well, possibly reflecting that each method assesses distinct aspects of bone architecture.

Evaluation of bone mineralization in former preterm born children: Phalangeal quantitative ultrasound cannot replace dual-energy X-ray absorptiometry

Background

Preterm infants are at risk of impaired bone health in later life. Dual-energy X-ray absorptiometry-scan (DXA) is the gold standard to determine bone mineralization. Phalangeal quantitative ultrasound (pQUS) is an alternative technique that is inexpensive, easy to use and radiation-free. The aim of this study was to investigate whether both techniques reveal equivalent results.

Materials and methods

Sixty former preterm infants (31 boys; 29 girls) received a DXA and pQUS at age 9 to 10 years. DXA measured bone mineral content (BMC) and bone mineral density (BMD) for total body and lumbar spine (L1-4), while pQUS measured the amplitude dependent speed of sound (AD-SoS) and bone transit time (BTT) at metacarpals II-IV providing continuous values and Z-scores based on age and sex. Four statistical methods evaluated the association between both techniques: Pearson's correlation coefficients, partial correlation coefficients adjusted for gestational age, height and BMI, Bland-Altman analysis and cross tabulation.

Results

Both techniques showed a statistically significant weak correlation for continuous values as well as Z-scores (0.291–0.462, p < 0.05). Boys had significant and relatively high correlations (0.468–0.585, p < 0.05). In comparison, the correlations for girls were not significant. Correlation coefficients further decreased while calculating the partial correlations. The Bland-Altman plots showed poor agreement. Sensitivity ranged from 33% to 92% and specificity from 16% to 68%. Positive and negative predictive values ranged from 4% to 38% and 82% to 97%, respectively.

Conclusions

We found statistically significant weak correlations and poor agreement between DXA and pQUS measurements. DXA is not equivalent to pQUS and therefore not replaceable by this technique in former preterm born children at the age of 9 to 10 years.

•

DXA is the golden standard to determine bone mineralization, while Quantitative ultrasound is a radiation-free alternative.

•

Four statistical tests were used to investigate the equivalence of both methods.

•

Comparison of results of 60 preterm born children at age 9 to 10 years found poor agreement between both methods.

•

There was a discrepancy in differentiating the same children with normal or reduced bone mineralization.

•

Quantitative ultrasound cannot replace the DXA scan for determination of bone mineralization in preterm born children.

Reference data for ultrasound bone characteristics in Hungarian children aged 7-19 years

Backround: Osteoporosis is a common disease and physical activity (PA) has a favourable influence on bone status.

AIM

To establish normative data for calcaneal quantitative ultrasound (QUS) bone characteristics in children and to analyse the relationships between PA, anthropometric and bone parameters.

SUBJECTS AND METHODS

Hungarian children aged 7-19 (n = 2674; 1325 girls, 1349 boys) provided PA, anthropometric and bone data. QUS parameters were registered with Sonost3000 densitometer (speed of sound: SOS, m/s; broadband ultrasound attenuation: BUA, dB/MHz; bone quantity index (BQI = αSOS + βBUA). Reference centiles of QUS parameters were constructed by LMS method. Multivariate linear regression models were used to analyse the relationships.

RESULTS

QUS bone parameters increased with age. There were no gender differences, except in 11- and 19-year-old children, where boys showed higher values. SOS (1497.15 ± 15.72 vs 1494.05 ± 14.81 m/s) and BQI (65.31 ± 16.71 vs 62.26 ± 15.78) were higher in athletic children. The regression model revealed significant relations between SOS and age, relative muscle mass and PA; BUA correlated with gender, morphological age, BMI, relative muscle mass and PA.

CONCLUSIONS

Changes in the bone parameters among 7-19-year-old Hungarian children depended on age, anthropometric dimensions and the level of PA. The normative data could be used for monitoring QUS bone parameters in children, leading to more effective interventions for healthy bones.

Evidence-based review of bone strength in children and youth with cerebral palsy

Children with cerebral palsy have various risk factors for compromised bone health. Evidence concerning their bone fragility is gathering; however, there is no consensus regarding risk factors, indications for evaluation, follow-up, or treatment. We performed an evidence-based review targeted to address the following questions concerning children with cerebral palsy: Is bone strength impaired and what are the risk factors? Are these children at increased risk for bone fractures? What are the relations between bone mineral density and fracture risk? What methods can be used for bone health assessment? How can bone strength be improved? Currently, the most acceptable method for evaluating bone status in children is dual-energy x-ray absorptiometry. Evidence demonstrates reduced bone mass in children with cerebral palsy; yet, no clear association with fractures. Preventive methods are suggested.

Contribution of stepping while standing to function and secondary conditions among children with cerebral palsy

PURPOSE

To explore the feasibility and efficacy of stepping while standing and its effect on function and prevalence of secondary conditions among children with severe cerebral palsy.

METHODS

Of 22 children with severe cerebral palsy, 11 underwent treatment using a Hart Walker (HW) device, and the other 11 underwent a passive standing program. Constipation prevalence and adverse events were recorded. Bone quantitative ultrasound was performed for the tibia. The Pediatric Evaluation of Disability Inventory was used to assess activities of daily life.

RESULTS

Children exposed to the HW improved bowel function, but no added quantitative benefit to bone was observed when compared with passive standing. Children using the HW were able to take steps independently in the device, but did not reach a functional walking level.

CONCLUSIONS

Providing a child who is nonambulatory the opportunity to walk may be important both for participation in activities of daily living and social roles and for preventing secondary conditions.

Bone development in children living on house-boats on a river in Vietnam

Background

With the rapid urbanization of Vietnam, living on boats has come to be associated with underprivileged socioeconomic status, and there are major concerns regarding the health of children living under such conditions. Bone development is a critical concern in children because the foundation for skeletal health is established early in life. We evaluated the bone properties of children living under underprivileged conditions on boats in Hue City, Vietnam, with respect to a number of household factors.

Methods

One hundred and twenty children aged 7-11 years selected randomly from households living on boats in Hue were included in this study. Tibial and radial speed of sound (SOS) were measured by non-invasive quantitative ultrasonometry. Socioeconomic profiles, health promotion proficiency, and nutritional intake of households were assessed by structured interview. The bone properties of 60 children aged 7-11 living on land were also assessed as controls.

Results

The Z-scores of tibial and radial SOS of boat children were -0.16 ± 0.89 and -0.24 ± 0.75 (mean ± SD), respectively. Tibial SOS exhibited a significant correlation with radial SOS (r = 0.39, P < 0.01). Among the household factors examined, the educational level of fathers (P < 0.05) and the health promotion proficiency (P < 0.05) of households exhibited positive associations with the tibial bone properties of the children. The tibial and radial SOS of boat children were lower than those of children living on land (P = 0.001 and P = 0.086, respectively).

Conclusion

The results of the present study revealed the underdevelopment of bone properties in children living on houseboats, which was correlated with their living conditions.

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.

Vitamin D receptor polymorphism among rickets children in Mongolia

BACKGROUND

It was reported that 32% of children under five years old in Mongolia had symptoms of rickets. Vitamin D receptor (VDR) gene polymorphism has received attention in relation to bone metabolism. We therefore investigated whether VDR polymorphism is related to high prevalence of rickets in Mongolia and to bone properties in childhood.

METHODS

We conducted a case-control study in Ulaanbaatar involving 80 children aged 7-10 years with a history of rickets (cases) and 72 children with no history of rickets (controls). VDR polymorphism was assessed using BsmI, ApaI, and TaqI, and bone properties were determined by measuring age-standardized midtibial cortical speed of sound (TCSOS).

FINDINGS

Each allelic frequency was verified to satisfy the Hardy-Weinberg equilibrium in cases, controls, and the total sample. The VDR polymorphisms among cases (BB 3%, Bb 18%, bb 80%; AA 15%, Aa 38%, aa 47%; and TT 81 %, Tt 17%, tt 3%) did not differ significantly from those among controls (BB 1%, Bb 13%, bb 86%; AA 16%, Aa 46%, aa 38%; and TT 86%, Tt 13%, tt 1%). There were no significant differences in TCSOS according to the VDR genotype among either cases or controls.

CONCLUSIONS

The VDR polymorphism does not play a major role in the development of rickets in Mongolia and has no effect on TCSOS in childhood.

Extracurricular sports activity around growth spurt and improved tibial cortical bone properties in late adolescence

AIM

To elucidate whether extracurricular sports activity during rapid growth correlates with improved bone properties in late adolescence, a longitudinal observation was performed among 96 high-school enrollments (46 boys and 50 girls, born in 1981-1982) in metropolitan Tokyo.

METHODS

In each year of high school, tibial cortical speed of sound (TCSOS) was measured by quantitative ultrasonometry, and participation in extracurricular sports activity (ECSA) since primary school was examined by structured questionnaire. We calculated the number of years since peak height velocity (ysPHV) based on annual records of height from 6 to 18 y of age to indicate progression of puberty.

RESULTS

The increase in TCSOS during high school in boys (32.5 m/s) was significantly greater than that in girls (5.4 m/s). The magnitude of positive association between ysPHV and TCSOS attenuated gradually over time. ECSA in grades 7-9 in boys and in grades 4-6 in girls were significant predictors of TCSOS throughout high school, independent of potential confounders.

CONCLUSION

The bone benefits of ECSA around the growth spurt are maintainable in subsequent years. The importance of physical activities that are integrated into the ordinary lifestyle of children and adolescents during this crucial period is emphasized.

Association of swaddling, rickets onset and bone properties in children in Ulaanbaatar, Mongolia

OBJECTIVES

To examine the influence of duration of completely or partially wrapped swaddling on rickets onset and bone properties in children of school age.

STUDY DESIGN

Case-control study.

METHODS

Subjects were 73 children aged 7-10 years with a history of rickets (cases) and 70 children with no history of rickets (controls) in Ulaanbaatar, Mongolia. The periods of completely and partially wrapped swaddling, rickets onset and age-standardized mid-tibial cortical speed of sound (TCSOS) were examined. The associations between swaddling duration and rickets onset and that between swaddling duration and TCSOS were analysed.

RESULTS

All except one control child were completely wrapped from the first month after birth. The durations of completely wrapped and partially wrapped swaddling were similar among cases (3.6 and 4.7 months) and controls (3.1 and 4.4 months) (P=0.42 and P=0.65, respectively). Standardized TCSOS values of cases and controls were -0.572 and -0.038, respectively (P=0.06). The duration of swaddling did not show associations with rickets onset and standardized TCSOS among both cases and controls. Standardized TCSOS of cases with skeletal deformities at examination (-1.467, n=18) was lower than that of cases without skeletal deformities (-0.280, n=55) (P<0.01) and controls (-0.038, n=69) (P<0.001).

CONCLUSIONS

The practice of swaddling itself neither influences rickets onset nor bone properties in school-aged children in Ulaanbaatar. Bone properties of school-aged children who had suffered from rickets and with skeletal deformities were poorer than those in children without skeletal deformities and children without a history of rickets. Prevention of persistent skeletal deformities among the children who have suffered from rickets is critical to promote healthy bone development in Mongolia.

Tibial cortical bone properties of preadolescents and their mothers in an urban area associated with lifestyle: a longitudinal study

AIM

A 12-mo follow-up observation was performed to evaluate the tibial cortical bone properties of preadolescent children and their mothers in a densely populated area of Tokyo in association with their lifestyle in the context of healthy bone development of urban children.

METHODS

Fifty-four volunteer mother-child pairs were examined twice: once in the 1st grade of elementary school and once in the following year. Tibial cortical speed of sound (TCSOS) was measured by non-invasive quantitative ultrasonometry. Nutritional intake and recreational activity were examined using a structured interview.

RESULTS

TCSOS of the children showed a positive association with intake of vegetables, including potatoes and fruits (1st grade, r = 0.31, p < 0.05; 2nd grade, r = 0.33, p < 0.05), and inversely correlated with indoor recreational activities (1st grade, r = -0.28, p < 0.05). The z-score of TCSOS of the mothers was correlated with intake of milk, dairy products and eggs (r = 0.35, p < 0.001). However, there were no statistically significant correlations in TCSOS between children and their mothers.

CONCLUSION

A 1-y longitudinal study in urban children indicated the effects of specific types of food intake and recreational activities of children on tibial bone properties.

Different diagnostic techniques for the assessment of cortical bone on osteoporotic animals

The aim of this study was to assess the capability of ultrasonography and densitometry to predict the mechanical competence of cortical bone in healthy and osteopenic rats, respectively. Thirty 10-month-old Sprague-Dawley retired breeder female rats were used and randomized into three groups of 10 animals each. A group underwent bilateral ovariectomy by dorsal approach (Ovx), another group underwent a simulated ovariectomy (Sham-Ovx), and the last group served as a sham-aged control group (Control). Sixteen weeks after surgery, the animals were euthanized and the femurs of each rat excised for ultrasonographic and densitometric measurements, and mechanical analyses. The Ovx Group had a significantly decreased amplitude dependent speed of sound (AD-SoS-about 7-8%) when compared to the other groups (p<0.0005). For Ovx animals compared with Sham-Ovx and Control rats, significant decreases in densitometric data were observed (6-13%), as well as significant decreases in femoral Max. Load (about 18%) and flexural rigidity (about 30%). The best correlation (R2=0.55, p<0.0005) found was between SoS and femoral shaft bone mineral density (SBMD). The regression coefficient R2 increased when power-law fits were used, particularly from 0.34 (p<0.001) to 0.36 (p<0.0005) in the correlation between SoS and Max. Load and from 0.21 (p<0.05) to 0.25 (p<0.01) in the correlation between SBMD and Max. Load. The ability of QUS or DXA to accurately predict the actual mechanical characteristics of bone, and in particular bone elasticity, remained relatively poor and the improvement of the power-law model did not describe exhaustively the relationships between the variables tested. The DXA and QUS capability to discriminate between ovariectomized and non-ovariectomized rats did not improve when tested together.

Osseous complications of pediatric transplantation

Adult stature and peak bone mass are achieved through childhood growth and development. Multiple factors impair this process in children undergoing solid organ transplantation, including chronic illness, pretransplant osteodystrophy, use of medications with negative impact on bone, and post-transplant renal dysfunction. While growth delay and short stature remain common, the most severe forms of transplant-related bone disease, fracture and avascular necrosis, appear to have become less common in the pediatric age group. Osteopenia is very prevalent in adult transplant recipients and probably also in pediatrics, but its occurrence and sequelae are difficult to study in these groups due to methodological shortfalls of planar densitometry related to short stature and altered patterns of growth and development. Although the effect on lifetime peak bone mass is not clear, data from adult populations suggest an elevated long-term risk of bone disease in children receiving transplants. Optimal management of pretransplantation osteodystrophy, attention to post-transplant renal insufficiency among both renal and non-renal transplant patients, reduction of steroid dose in select patients, and supplementation with calcium plus vitamin D during expected periods of maximal bone loss may improve bone health. Careful research is required to determine the role of bisphosphonate therapy in pediatric transplantation.

Bone quantitative ultrasound and nutritional status in severely handicapped institutionalized children and adolescents

BACKGROUND & AIMS

Children with cerebral palsy (CP) have a high prevalence of pathologic fractures. Bone quantitative ultrasonography (QUS) has emerged as a radiation-free method for the assessment of bone quality and fracture risk. In this study, we applied QUS technique in order to investigate bone status in handicapped institutionalized children and adolescents.

METHODS

This cross-sectional study included 87 handicapped institutionalized patients. Measurements of the velocity of ultrasound wave, speed of sound (SOS), at distal radius and midshaft tibia, were performed using Omnisense 7000S analyser (Sunlight Ltd., Tel Aviv, Israel). In addition, all the participants had a thorough evaluation of nutritional status, demographic and clinical characteristics.

RESULTS

Forty-five of patients had either radius or tibia bone SOS lower than -1 SD, and 21% had either radius or tibia bone SOS lower than -2.5 SD. Using step-wise regression analysis, female gender (P=0.003) and stature (P=0.008) were correlated with radius SOS. Age (P=0.03) and fracture history (P=0.04) were negatively correlated with tibia SOS.

CONCLUSION

In this group of children and adolescents with CP one-fifth had poor bone status as suggested by low tibia/radius SOS assessed by QUS. Female gender, stature, age and fracture history were significantly correlated with poor bone status.

The use of quantitative ultrasound in assessing bone status in newborn preterm infants

OBJECTIVE

Quantitative ultrasound is increasingly used to assess bone status in adults and children; however, few studies have been carried out in neonates. Our objective was to determine if tibial bone speed of sound (SOS) correlates with gestational age and birth anthropometrics, and if bone SOS is related to maternal factors.

STUDY DESIGN

We prospectively studied 95 preterm infants to assess factors related to bone status as measured by quantitative ultrasound.

RESULTS

We found significant (p< or =0.001) positive correlations between SOS and gestational age, birth weight, length, head circumference and tibial length. There was no significant relationship between SOS and prenatal steroid use, gestational diabetes, pre-eclampsia, race or parity.

CONCLUSIONS

Quantitative ultrasound is an easy to use and inexpensive tool for assessing bone status in preterm neonates. Tibial SOS correlated with gestational age and birth anthropometrics, and was not related by few maternal factors.