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Journal of Thyroid Research
Volume 2015 (2015), Article ID 796871, 9 pages
http://dx.doi.org/10.1155/2015/796871
Research Article

Bone Indices in Thyroidectomized Patients on Long-Term Substitution Therapy with Levothyroxine Assessed by DXA and HR-pQCT

Department of Endocrinology and Internal Medicine, THG, Aarhus University Hospital, 8000 Aarhus C, Denmark

Received 13 March 2015; Accepted 22 June 2015

Academic Editor: Massimo Tonacchera

Copyright © 2015 Emil Moser et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background. Studies on bone effects of long-term substitution therapy with levothyroxine (LT4) have shown discrepant results. Previous studies have, however, not evaluated volumetric bone mineral densities (vBMD), bone structure, and strength using high resolution peripheral quantitative computed tomography (HR-pQCT) and finite element analysis (FEA). Using a cross-sectional design, we aimed to determine whether BMD, structure, and strength are affected in hypothyroid patients on LT4 substitution therapy. Methods. We compared 49 patients with well-substituted hypothyroidism with 49 age- and gender-matched population based controls. Areal BMD was assessed by DXA, vBMD and bone geometry by HR-pQCT, and bone strength by FEA. Results. Patients had been thyroidectomized due to thyroid cancer (10%) and nontoxic (33%) or toxic goiter (57%). 82% were women. TSH levels did not differ between groups, but patients had significantly higher levels of T4 () and lower levels of T3 (). Compared to controls, patients had higher levels of magnesium (), whereas ionized calcium and PTH were lower (). Bone scans did not reveal any differences in BMD, bone geometry, or strength. Conclusion. If patients with hypothyroidism are well-substituted with LT4, the disease does not affect bone indices to any major degree.