title: Longitudinal changes of bone density and bone resorption in hyperthyroid girls during treatment.
abstract: Low bone mineral density (BMD) and increased bone turnover are common features of untreated hyperthyroidism in adult patients. The effect of treatment on BMD is still controversial. BMD and bone metabolism in hyperthyroid children have not been thoroughly investigated. In the present study, we measured spinal and whole body BMD by dual-energy X-ray absorptiometry in a group of 13 girls (aged 5.0-14.9 years) at diagnosis of hyperthyroidism. The bone resorption rate was assessed by urine measurement of N-terminal telopeptide of type I collagen (NTX). Hyperthyroid patients have been studied longitudinally during treatment. BMD values and NTX urine concentrations have been also determined in 155 healthy Caucasian girls (aged 2.4-24.2 years). Spinal and whole body bone density measurements were significantly lower compared with healthy controls in untreated hyperthyroid girls, after correction for differences in age and anthropometric measurements (p </= 0.033). Bone density measurements obtained after 12 and 24 months of treatment were no longer different from those of healthy girls. NTX urine levels at diagnosis of thyrotoxicosis were significantly higher than those found in healthy controls (p < 0.0001); 6 months after treatment, the urine levels did not show significant differences, and they remained stable after 12 and 24 months of therapy. Inverse correlations at diagnosis were found between serum-free thyroxine (FT4) serum levels and spinal (r = -0.42) and whole body bone density (r = -0.41); FT4 and free triiodothyronine serum levels directly correlated with the NTX concentration (r = 0. 77, and r = 0.71, respectively). In conclusion, the results of the present study demonstrate that low bone density values and high bone resorption rates are found in hyperthyroid children and adolescents at diagnosis of the disease. Our data also demonstrate that antithyroid treatment is able to reduce dramatically the bone resorption and to increase significantly both spinal and total body BMD, granting physiologic conditions for the achievement of the best obtainable peak bone mass.
authors.affiliation: Laboratory of Pediatric Endocrinology, Department of Pediatrics, Scientific Institute H San Raffaele, University of Milan, Milan, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Mora
authors.forename: G
authors.initials: G
authors.lastname: Weber
authors.forename: K
authors.initials: K
authors.lastname: Marenzi
authors.forename: E
authors.initials: E
authors.lastname: Signorini
authors.forename: R
authors.initials: R
authors.lastname: Rovelli
authors.forename: M C
authors.initials: MC
authors.lastname: Proverbio
authors.forename: G
authors.initials: G
authors.lastname: Chiumello
mesh_terms: D000293:Adolescent; D000328:Adult; D013956:Antithyroid Agents / Q000627:therapeutic use*; D015415:Biomarkers; D015519:Bone Density / Q000187:drug effects; D001862:Bone Resorption; D002648:Child; D002675:Child, Preschool; D003094:Collagen / Q000652:urine; D024042:Collagen Type I; D003404:Creatinine / Q000652:urine; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood / Q000188:drug therapy / Q000503:physiopathology* / Q000652:urine; D008137:Longitudinal Studies; D008713:Methimazole / Q000627:therapeutic use*; D010455:Peptides / Q000652:urine; D013971:Thyrotoxicosis / Q000097:blood / Q000188:drug therapy / Q000503:physiopathology / Q000652:urine; D013974:Thyroxine / Q000097:blood
chemical_list: D013956:Antithyroid Agents; D015415:Biomarkers; D024042:Collagen Type I; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D008713:Methimazole; D003094:Collagen; D003404:Creatinine; D013974:Thyroxine