Reduced Forearm Bone Mineral Content and Biochemical Evidence of Increased Bone Turnover in Women With Euthyroid Goitre Treated With Thyroid Hormone

SUMMARY We used single‐photon absorptiometry to assess forearm bone mineral content (BMC/BW) (arbitrary units normalized for bone width) at a proximal site (PBMC/BW) and at a more distal site (DBMC/BW) in 60 women treated with 25–50 μg T3 or 50–100 μg T4 for euthyroid goitre, in 13 untreated goitre patients, and in 2 controls matched for age and menopausal state for each goitre patient. BMC/BW was not significantly different between untreated goitre patients and controls. In 36 premenopausal patients, treated for 5.8 |Mp 5.4 years (mean |Mp SD) a slight decrease in PBMC/BW of about 5% compared to controls was observed (PBMC/BW 1.42 |Mp 0.19 vs 1.49 |Mp 013, P< 0.05). In 24 postmenopausal patients, treated for 10.0 |Mp 5.8 year, a 20% deficit in BMC/BW compared to controls was found (DBMC/BW 0.80 |Mp 0.18 vs 1.06 |Mp 0.20, P < 0.001 and PBMC/BW 1.14 |Mp 0–20 vs 1.42 |Mp 0.19, P < 0.001). Biochemical indices of bone metabolism in 43 pre and post‐menopausal patients and 43 controls showed in the patients a higher serum alkaline phosphatase activity (AP) (P < 0.01 and P < 0.05) and serum osteocalcin (NS and P < 0.05). AP was negatively correlated with TSH levels and, in postmenopausal patients, with DBMC/BW and PBMC/BW. Our results suggest that treatment of euthyroid women with moderate doses of thyroid hormone increases bone turnover with clear adverse effects on bone mineral status in postmenopausal patients.