Cinzia Ceccarelli

Bone turnover in children with vitamin D deficiency rickets before and during treatment

Biochemical markers of bone formation [alkaline phosphatase, osteocalcin, and carboxyterminal propeptide of type I procollagen (PICP)] and bone resorption [cross‐linked carboxyterminal telopeptide of type I collagen (ICTP) and cross‐linked N‐telopeptides of type I collagen (NTX)] were measured in 14 children aged 8.5–10.5 mo with vitamin D deficiency rickets before and longitudinally during vitamin D treatment (3000–4000 IU/daily). Forty‐four healthy children aged 8–10.5 mo were enrolled as sex‐ and age‐matched controls. Before treatment, serum levels of alkaline phosphatase, PICP, and ICTP, and urinary excretion values of NTX were significantly higher, and serum osteocalcin levels significantly lower than controls (31.4 ± 3.5 mμkat/L and 9.8 ± 2.9 μkat/L, p < 0.001; 1025 ± 89 μg/L and 952 ± 97.4 μg/L, p < 0.02; 15.6 ± 2.6 μg/L and 14.2 ± 1.3 μg/L, p< 0.01 370.7 ± 109.4 nmol BCE and 201.8 ± 69.2 nmol BCE, p < 0.001; 17.6 ± 9.1 μg/L and 22.5 ± 7.6 μg/L, p <0.05, respectively). During treatment, serum alkaline phosphatase levels progressively declined in association with the radiographic healing of the skeletal lesions. Serum levels of osteocalcin, PICP, and ICTP, and urinary excretion values of NTX showed a transient but significant (p < 0.05 to p < 0.001) increase in comparison with baseline values during the first 2–4 wk of treatment, and decreased slowly thereafter. They were within the mean 2 SD of controls before the recovery of the skeletal lesions.

Bone mineral density in adolescent females treated with L-thyroxine : a longitudinal study

It has been suggested that chronic treatment withl-thyroxine (l-T4) could be implicated in reducing bone mineral density (BMD). The purpose of this longitudinal study was to determine whether appendicular and axial BMD is decreased byl-T4 treatment in adolescent girls. Thirteen adolescent girls with subclinical hypothyroidism caused by chronic lymphocytic thyroiditis were enrolled in the study at the median age of 13.4 years (range 9.2–18.1 years).l-T4 was administered in a single dose of 1–5 μg/kg daily. BMD was evaluated at the distal one-third of the non-dominant radius by single photon absorptiometry (SPA) and at the lumbar spine (L2–4) by dual energy X-ray densitometry (DEXA). Osteocalcin levels were measured to assess bone turnover before and duringl-T4 treatment. Before the start of therapy, mean BMD at both the radial and lumbar level was not significantly different from that of a control group (median age 13.0 years; range 9.0–18.5 years). Duringl-T4 therapy for 2–5 years, BMD did not change at any site. Before treatment, osteocalcin levels were not significantly different from those of controls and did not change during follow up.ConclusionLong-terml-T4 therapy in adolescent girls has no adverse effect on BMD and bone turnover. Our data indicate that attainment of peak bone mass is not impaired byl-T4 administration.

Vitamin-D Receptor Genotype Does Not Predict Bone Mineral Density, Bone Turnover, and Growth in Prepubertal Children

We examined whether the polymorphism for BsmI restriction enzyme in the vitamin-D receptor (VDR) gene influenced radial (distal third) and lumbar (L2–L4) bone mineral density (BMD), phospho-calcium metabolism (calcium, phosphate, intact parathyroid hormone, 25-hydroxyvitamin D, and 1,25-dihydroxyvitamin D), biochemical markers of bone formation (osteocalcin and carboxy-terminal propeptide of type-I procollagen) and bone resorption (carboxy-terminal telopeptide of type-I collagen and urinary cross-linked N-telopeptides of type I collagen), insulin-like growth factor I and insulin-like growth factor-binding protein 3, and growth in 209 healthy prepubertal children (112 males and 97 females) aged 7.1–10.0 years. Genotype frequencies were BB 19%, Bb 46%, and bb 35% in the pooled group of children. Clinical findings, dietary calcium intake, calcium density, and physical activity rate were not different (p NS) among the VDR genotypes. Radial BMD, lumbar BMDarea and lumbar BMD adjusted for the apparent bone volume (BMDvolume), and all the biochemical parameters did not differ (p NS) in relation to the VDR genotype. In conclusion, our data show that polymorphism for BsmI restriction enzyme in the VDR gene is not associated with radial and lumbar BMD, parameters of phospho-calcium metabolism and bone turnover, growth hormone-dependent growth factors, and growth in prepubertal children.