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. (Pediatr Res 63: 220-228, 2008) I n the last years, the demand for measurement of bone mineral status to identify children who could be exposed to an increased risk of osteoporosis in adulthood is rapidly increased. Several disorders, by various mechanisms, may be associated with a reduced bone mineral status; in particular, patients with chronic or genetic diseases, malignancies, acute or chronic disabilities caused by neuromuscular disorders, and patients receiving prolonged glucocorticoid treatment are at risk of fractures by minimal trauma caused by a severe reduction in bone mineral status (1).Moreover, there is a growing demand for assessing the effects of some environmental factors on bone health, such as dietary habits and various degrees of physical activity by using radiationfree techniques. DENSITOMETRIC TECHNIQUES FOR ESTIMATING BONE MINERAL STATUS IN CHILDRENSome densitometric techniques to assess bone mineral status developed for adults have been adapted for the use in children. Dual energy x-ray absorptiometry (DXA) is the most commonly used technique for bone mineral status assessment worldwide. The main advantages of DXA are its wide availability and short scanning times, but the subject is exposed to ionized radiation that varies according to the machinery and the examined skeletal site; anyway, radiation dose to patient from DXA is minimal (0.08 -4.6 Sv and 6.7-31 Sv for pencil beam and fan beam methods, respectively) compared with that given by many other investigations involving ionizing radiation (2). Nevertheless, an important shortcoming of DXA is that it measures bone in two dimensions providing only an estimation of bone density. Indeed, DXA measures an integral areal density that is calculated as bone mineral content/bone su...

In Turkey most patients had vitamin D deficiency, whereas in Egypt they had mostly calcium insufficiency combined with vitamin D deficiency. In this environ, VDR genotypes may predispose to rickets by increased frequency of the F allele. The unique environs and genetic predisposition have to be accounted for in the design of preventive measures, rather than using European or American recommended dietary intake for calcium and vitamin D.

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Bisphosphonates are widely used for the prevention and treatment of osteoporosis in adulthood. In the last years, bisphosphonates have been increasingly used in pediatric patients for the treatment of a growing number of disorders associated with osteoporosis, resistant hypercalcemia or heterotopic calcifications. The use of bisphosphonates in pediatric patients has been proven safe; however, the risk of potential severe consequences into adulthood should be kept in mind. Well-defined criteria for bisphosphonates treatment in pediatric patients are not specified, therefore an accurate selection of patients who could benefit from bisphosphonates is mandatory. A strict follow-up of pediatric patients receiving long-term bisphosphonate therapy is strongly recommended. The purpose of this mini review is to provide a summary of current knowledge on some main general aspects of the structure, mechanisms of action, pharmacokinetics, and bioavailability of bisphosphonates, and to focus on the latest advances of bisphosphonate treatment in pediatric patients. Particular attention has been paid to the common and potential adverse effects of bisphosphonate treatment, and some suggestions concerning the clinical approach and general measures for bisphosphonate treatment in pediatric patients are reported.

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Bone turnover, collagen metabolism, and bone mineral status were investigated in 59 patients with cystic fibrosis and in 72 sex and age-matched control subjects. In all patients and control subjects serum concentrations of osteocalcin (OC), carboxy-terminal propeptide of type I procollagen (PICP), amino-terminal propeptide of type III procollagen (PIIINP), and cross-linked carboxy-terminal telopeptide of type I collagen (ICTP), and urinary values of cross-linked N-telopeptides of type I collagen (NTX), as well as total body bone mineral content (TBBM) were measured. Higher ICTP (microgram/L) and NTX (bone collagen equivalent/urinary creatinine (nmol/mmol) values were found in pre-pubertal, pubertal, and young adult patients than in control subjects (ICTP: 15.4 +/- 2.1 and 13.2 +/- 1.8, p < 0.001; 23.3 +/- 5.3 and 20.1 +/- 4.1, p < 0.02; 4.8 +/- 1.1 and 4.0 +/- 1.0, p < 0.05. respectively; NTX: 1047.5 +/- 528.6 and 227.8 +/- 71.8, p < 0.01; 997.8 +/- 391.7 and 376.3 +/- 91.0, p < 0.01; 993.2 +/- 398.0 and 73.9 +/- 28.5, p < 0.01, respectively). Lower OC and PICP levels (microgram/L) were showed in pubertal patients in comparison with control subjects (OC: 20.2 +/- 12.3 and 39.0 +/- 15.1, p < 0.01; PICP: 305.8 +/- 130.4 and 436.2 +/- 110.1, p < 0.02, respectively). Lower OC and higher PIIINP levels (microgram/L) were found in young adult patients than in control subjects (OC: 4.4 +/- 3.0 and 7.0 +/- 3.1, p < 0.05; PIIINP: 4.8 +/- 1.1 and 3.1 +/- 1.0, p < 0.001, respectively). TBBM (z score) was reduced in prepubertal, pubertal, and young adult patients (-0.8 +/- 0.4, -1.0 +/- 0.4, -1.1 +/- 0.5, respectively). Patients with cystic fibrosis have bone demineralization and imbalance between bone formation and degradation.

Bone quality by quantitative ultrasound and fracture rate were assessed in 135 (64 males) children and adolescents aged 3-21 y with bone and mineral disorders such as chronic anticonvulsants or glucocorticoids treatment, juvenile rheumatoid arthritis, celiac disease, paucity of intrahepatic bile ducts, autoimmune hepatitis, genetic diseases, idiopathic juvenile osteoporosis, disuse osteoporosis, ␤-thalassemia major, survivors of acute lymphoblastic leukemia, liver transplantation, calcium deficiency, and nutritional or X-linked hypophosphatemic rickets. Amplitude-dependent speed of sound through the distal end of the first phalangeal diaphysis of the last four fingers of the hand was measured by an ultrasound device. In the majority of patients cortical area to total area ratio by metacarpal radiogrammetry (n ϭ 120) and lumbar bone mineral density (BMD) by dual-energy x-ray absorptiometry (n ϭ 99) were also assessed. In patients with X-linked hypophosphatemic rickets radial BMD by single-photon absorptiometry instead of lumbar BMD was measured. Mean values of amplitude-dependent speed of sound, cortical area to total area ratio, lumbar BMDarea, or lumbar BMD corrected for bone sizes estimated by a mathematical model (BMDvolume), as well as mean values of radial BMD in patients with X-linked hypophosphatemic rickets, expressed as z score, were significantly reduced (p Ͻ 0.0001) in comparison with their reference values (Ϫ1.7 Ϯ 1.0, Ϫ2.0 Ϯ 0.9, Ϫ3.0 Ϯ 1.3, Ϫ1.9 Ϯ 1.0, Ϫ2.7 Ϯ 0.7, respectively). A positive relationship was found between amplitudedependent speed of sound and cortical area to total area ratio (r ϭ 0.90, p Ͻ 0.0001), lumbar BMDarea (r ϭ 0.62, p Ͻ 0.0001), or lumbar BMDvolume (r ϭ 0.66, p Ͻ 0.0001). Fifty-two patients (38.5%) had suffered fractures in the 6 mo preceding the bone measurements, the radial distal metaphysis being the most frequent fracture site (28.8%). Mean values of amplitude-dependent speed of sound, cortical area to total area ratio, lumbar BMDarea, or lumbar BMDvolume, expressed as z score, of fractured patients were significantly lower (p Ͻ 0.0001) than those of fracture-free patients (Ϫ2.2 Ϯ 1.0 and Ϫ1.4 Ϯ 0.8, Ϫ2.6 Ϯ 0.9 and Ϫ1.7 Ϯ 0.7, Ϫ3.5 Ϯ 1.2 and Ϫ2.5 Ϯ 1.0, Ϫ2.5 Ϯ 1.0 and Ϫ1.3 Ϯ 0.7, respectively). Phalangeal quantitative ultrasound may be a useful method to assess bone quality and fracture risk in children and adolescents with bone and mineral disorders. DXA has been widely accepted as a noninvasive method for BMD measurement in adults as well as in pediatric subjects (1). An important shortcoming of DXA is that it measures an areal density, so that in growing children BMD is closely related to anthropometric findings and bone sizes (2). Correction of the amount of mineral measured for the apparent bone sizes (BMDvolume) may be a useful tool to reduce the large biologic variation in BMD measurements caused mainly by the confounding influence of age-related changes in bone geometry (2-4).Bone mass studies have recently revitalized the use of metacarpal radiogrammetry to asse...