title: Bone mineral density and bone microarchitecture after long-term suppressive levothyroxine treatment of differentiated thyroid carcinoma in young adult patients.
abstract: Bone mineral density (BMD) seems not to be decreased in young patients given long-term suppressive doses of levothyroxine (LT4), but information regarding the bone microstructure in these patients is lacking. The aim of this study was to determine whether supraphysiologic doses of LT4, initiated during childhood or adolescence for treatment of differentiated thyroid carcinoma (DTC), have any detrimental effects on bone microarchitecture as evaluated by high-resolution peripheral quantitative computed tomography (HR-pQCT). Seventeen patients (27.3 ± 7.1 years old) with DTC with subclinical hyperthyroidism since adolescence and 34 healthy volunteers matched for age, sex, and body mass index were studied by dual-energy X-ray absorptiometry (DXA) to determine the areal BMD at the lumbar spine, hip, and proximal third of the radius. Volumetric BMD and structural parameters of the trabecular and cortical bone were assessed by HR-pQCT of the distal radius and distal tibia. DTC patients were given suppressive doses of LT4 starting at a mean age of 12.6 years, and the mean duration of treatment was 14.2 years. In DTC patients, clinical parameters did not correlate with DXA or HR-pQCT parameters. No differences were found between the patients and controls with respect to BMD and Z scores at any site evaluated by DXA, and no differences were found in the bone microstructure parameters evaluated by HR-pQCT. This cross-sectional study suggests that long-standing suppressive therapy with LT4 during the attainment of peak bone mass may have no significant adverse effects on bone density or microarchitecture.
authors.affiliation: Division of Endocrinology, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Graziella
authors.initials: G
authors.lastname: Mendonça Monteiro de Barros
authors.affiliation: Division of Endocrinology, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. miguelmadeira@cremerj.org.br.
authors.forename: Miguel
authors.initials: M
authors.lastname: Madeira
authors.affiliation: Division of Endocrinology, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Vieira Neto
authors.affiliation: Division of Endocrinology, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Francisco
authors.initials: F
authors.lastname: de Paula Paranhos Neto
authors.affiliation: Division of Rheumatology, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Laura Maria
authors.initials: LM
authors.lastname: Carvalho Mendonça
authors.affiliation: Laboratory of Nuclear Instrumentation-COPPE, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Inayá
authors.initials: I
authors.lastname: Corrêa Barbosa Lima
authors.affiliation: Division of Endocrinology, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.|Instituto Nacional do Câncer, Rio de Janeiro, Brazil.
authors.forename: Rossana
authors.initials: R
authors.lastname: Corbo
authors.affiliation: Division of Endocrinology, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Maria Lucia
authors.initials: ML
authors.lastname: Fleiuss Farias
mesh_terms: D000293:Adolescent; D000328:Adult; D015519:Bone Density / Q000187:drug effects*; D001938:Brazil; D003430:Cross-Sectional Studies; D006801:Humans; D008875:Middle Aged; D011884:Radius / Q000378:metabolism* / Q000473:pathology; D013964:Thyroid Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D013974:Thyroxine / Q000008:administration & dosage* / Q000009:adverse effects; D055815:Young Adult
chemical_list: D013974:Thyroxine
keywords: Bone density; Osteoporosis; Thyroid cancer