Quantitative ultrasound detects bone changes following bone marrow transplantation in pediatric subjects with hematological diseases: a longitudinal study

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.

Comparison of International Reference Values for Bone Speed of Sound in Pediatric Populations: Meta-analysis

The aim of this study was to compare international reference values (RV) for tibial and radial speed of sound (SoS) assessed by quantitative ultrasound (QUS) in pediatric populations. These values were compared by age and country of origin in a systematic review with meta-analysis from studies published on QUS (Sunlight Omnisense). A search was carried out in electronic databases. Nine studies with 6963 patients were included in the meta-analysis. For the newborn populations, 3 studies (from Italy, Portugal, and Israel) were used. These studies included subjects with 27-42 wk gestational age. The mean difference (Portugal-Israel) was found to be 23.62 m/s [95% confidence interval [CI] 6.29, 40.95]. Additionally, no difference was found between Italy-Portugal (p = 0.69), or Italy-Israel (p = 0.28). In pediatric populations, we compared 8 studies from Canada, Mexico, Israel, Greece, Portugal, and Turkey. No significant differences found for SoS RV between Israel-Turkey, Israel-Greece, or Israel-Canada (p > 0.05). Significant differences were found in Mexico-Israel -105.29 m/s (95% CI -140.05, -70.54) (p < 0.001); Mexico-Portugal -115.14 m/s (95% CI -164.86, -65.42) (p < 0.001); Mexico-Greece: -239.14 m/s (95% CI -267.67, -210.62) (p < 0.001); Mexico-Turkey: -115.14 m/s (95% CI -164.86, -65.42) (p < 0.001); Mexico-Canada: -113.51 m/s (95% CI -140.25, -86.77) (p < 0.001).This study demonstrates that there are differences in SoS-RV obtained by tibial and radial QUS in pediatric populations between Mexico and other countries (Israel, Portugal, Greece, Turkey, and Canada).

Bone loss and vitamin D deficiency in children undergoing hematopoietic cell transplantation

BACKGROUND

Hematopoietic cell transplantation (HCT) may be detrimental to bone health and vitamin D status in children.

PROCEDURE

We conducted a prospective, multicenter cohort study to identify changes in bone health markers during the first 100 days after allogeneic HCT in 26 children. Bone mineral density (BMD), bone mineral content (BMC), and serum 25-hydroxyvitamin D (25OHD) concentrations were measured at baseline, 30 days, and 100 days after HCT.

RESULTS

Mean (SD) BMD and BMC Z-scores (-0.48 ± 1.09 and -0.98 ± 1.26, respectively) were normal at baseline. Repeated-measures analysis revealed significant declines in BMD and BMC Z-scores over the 100 day study period, when adjusted for age, sex, Tanner stage, lean mass, fat mass, resting energy expenditure, total energy intake, insulin sensitivity, serum phosphorus, and inpatient steroid intake. Adjusted mean (SE) 25OHD concentrations declined from 29.2 (3.1) ng/ml at baseline, to 17.7 (1.8) ng/ml at 100 days after HCT. Vitamin D deficiency (25OHD <20 ng/ml) was present in 50% of patients 100 days after HCT.

CONCLUSIONS

Significant bone loss and vitamin D deficiency occur in children in the first 100 days following allogeneic HCT. Strategies to diminish acute bone loss during HCT in children are needed.