Ultrasound parameters and markers of bone turnover in hyperthyroidism: a longitudinal study.

Hyperthyroid patients are characterized by accelerated bone turnover leading to bone mass loss. The aim of this study was to assess changes in quantitative ultrasound [QUS] parameters, bone mineral density (BMD), and biochemical markers of bone turnover in patients prior to and after the onset of hyperthyroid treatment. A 2-yr longitudinal study was performed on 10 women recently diagnosed with Grave's disease after starting antithyroid therapy. Six patients were postmenopausal. All patients showed evidence of thyrotoxicosis as indicated by suppressed serum TSH and high levels of total serum thyroxine. They received antithyroid therapy (methimazole and/or 131I radiodine). QUS parameters were measured using an Achilles ultrasound unit and BMD was assessed by dual-energy X-ray absorptiometry (DXA). Thyroid hormones and markers of bone turnover were determined at baseline and 6, 12, and 24 mo after the onset of treatment.Stiffness, broadband ultrasound attenuation (BUA), and speed of sound (SOS) were low at baseline compared to normal values for the same age range and increased after 2 yr of treatment. A significant increase in BMD of the lumbar spine, total skeleton, and skeletal regions (legs) was also observed after treatment. Recovery of stiffness was almost complete at 12 mo. No significant elevation was observed between 12 and 24 mo. Stiffness increased 7.6%, 10.4%, and 10.4% after 6 mo (p < 0.02), after 1 yr (p < 0.02), and after 2 yr, respectively. No significant increase in SOS and BUA was observed between 12 and 24 mo. Furthermore, recovery of total skeleton and lumbar spine BMD continued throughout the study. Successful antithyroid therapy produced a rapid increase in QUS parameters (Stiffness) and spine BMD and femoral neck during the first year of treatment and a slower increment in total skeleton (up to 24 mo). Overall, ad integrum restitution was not observed in QUS or BMD.

Estimating body fat and lean tissue distribution in hyperthyroidism by dual-energy X-ray absorptiometry.

Body composition (fat mass, lean tissue, and bone mineral content), was determined by dual-energy X-ray absorptiometry (DEXA) at baseline and 6, 12, and 24 mo after treatment of hyperthyroidism. Ten women with Graves' disease were included in this study. Suppressed serum TSH and high total serum thyroxine levels were found in all patients. The patients received antithyroid therapy (methimazol and/or (131) I radioiodine). Lean tissue, bone mass, and body weight increased after 2 yr of euthyroidism. Total body lean mass increased from 32.3+/-3.9 kg to 35.2+/-4.1 kg (p < 0.005). Total lean mass increased from 10.6 +/- 1.8 kg to 11.6 +/- 1.9 kg (p < 0.01) in the legs, from 3.6 +/- 0.8 kg to 4.0 +/- 0.7 kg (p < 0.02) in the arms, and 16.0 +/- 1.6 kg to 17.4+/-1.8 kg (p < 0.005) in the trunk. Total-body fat mass increased from 19.9 +/- 6.6 kg to 21.2 +/- 7.6 kg (ns). At 1-yr, regional analysis disclosed that fat mass had increased in the trunk from 8.9 +/- 2.9 kg to 10.9 +/- 3.9 kg (p < 0.04) and from 2.3 +/- 0.9 kg to 3.2 +/- 1.2 kg in the arms (p < 0.04). After 2 yr of treatment, fat tissue remained unchanged in all of the studied regions. The results obtained herein suggest that, compared to initial values, the treatment of hyperthyroidism restore body weight. This increase is mainly the result of recovery of lean mass, predominantly in the limbs and trunk. This study provides new data on the patterns of change in body composition occurring in hyperthyroid patients during a 24-mo follow-up after attaining euthyroidism.