Hyperthyroidism influences ultrasound bone measurement on the Os calcis.

The objective of our study was to compare bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA) and quantitative ultrasound (QUS) parameters in women with hyperthyroidism and controls. In this cross-sectional study, QUS parameters and BMD values observed in untreated hyperthyroid patients were compared with data obtained from age-matched controls. Twenty-four women with Graves' disease were studied. Eight patients were postmenopausal. All patients had evidence of thyrotoxicosis as indicated by a raised total serum thyroxine and a suppressed serum thyroid stimulating hormone. BMD of the hip, lumbar spine and whole body, and body composition, were measured by DXA. Ultrasound evaluation on the os calcis was performed with an Achilles device. All measurements were performed before antithyroid therapy. The QUS parameters of BUA, SOS and Stiffness were significantly lower in hyperthyroid patients than in controls. Similar results were observed for the BMD of lumbar spine, femoral neck and total skeleton. Lean tissue and fat mass were also significantly decreased in hyperthyroid patients. In conclusion, these findings suggest that hyperthyroidism affects cortical and trabecular bone equally, as well as bone quality. QUS measurements may be helpful for assessing, using a simple and non-irradiating method, the bone effects of thyrotoxicosis.

Bone mineral density after renal transplantation in children.

Longitudinal bone mineral changes after renal transplantation were studied in 14 children aged 8 +/- 4 years. Combination immunosuppressive therapy was given to all patients (prednisone, azathioprine, cyclosporine). Bone mineral density (BMD) measurements of the first through fourth lumbar vertebrae by dual-energy X-ray absorptiometry were performed within 1 year preceding renal transplantation and 6, 12, and 24 months afterward (M0, M6, M12, and M24, respectively). The results of BMD obtained in grams of hydroxyapatite per square centimeter of spine projected area were subsequently transformed to standard deviation scores for a normal pediatric population. In addition, we used a mathematical spine volume correction to give the results in grams per cubic centimeter. All patients had a well-functioning renal graft at M6, M12, and M24 and a normal serum creatinine level. Significant decreases in BMD, standard deviation score, and spine volume-corrected BMD were observed 6 months after renal transplantation (p < 0.05, p < 0.01, and p < 0.01 respectively); the median loss of BMD and spine volume-corrected BMD was 9.2% and 15.6% at M6, respectively, and the median serum parathyroid hormone level dropped from 125 to 34 pg/ml. Between M6 and M12, BMD increased significantly up to 95% (median) of pretransplantation values and reached 97.2% (median) at M24. Similar but less marked improvement was observed in spine volume-corrected BMD results, reaching 87.7% and 87.4% at M12 and M24, respectively. A negative correlation was found between the cumulative prednisone dose and BMD in grams per square centimeter at M6 (r2 = 0.603; p = 0.006), M12 (r2 = 0.532; p = 0.015), and M24 (r2 = 0.40; p = 0.014). There was no correlation between cumulative prednisone dose and spine volume-corrected BMD or standard deviation score. Mean 6-month cyclosporine levels did not correlate with any measure of BMD. We conclude that after renal transplantation children have a significant decrease of BMD during the first 6 months after the operation, despite normal graft function and growth improvement.