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

Abstract

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 micrograms T3 or 50-100 micrograms 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 +/- 5.4 years (mean +/- SD) a slight decrease in PBMC/BW of about 5% compared to controls to controls was observed (PBMC/BW 1.42 +/- 0.19 vs 1.49 +/- 0.13, P less than 0.05). In 24 postmenopausal patients, treated for 10.0 +/- 5.8 year, a 20% deficit in BMC/BW compared to controls was found (DBMC/BW 0.80 +/- 0.18 vs 1.06 +/- 0.20, P less than 0.001 and PBMC/BW 1.14 +/- 0.20 vs 1.42 +/- 0.19, P less than 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 less than 0.01 and P less than 0.05 and serum osteocalcin (NS and P less than 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.

Bone Mineral Density in Children and Adolescent Females Treated with High Doses of L·Thyroxine

“…Low levels of PTH increase the urinary excretion of calcium and low levels of 1,25-dihydroxyvitamin D* impair the active intestinal calcium absorption [15], which leads to bone loss. Our results show a significant reduction (p < 0.002) in PBMC but not in DBMC of the distal forearm, in accor dance with the literature [7], since the proximal site is more representative of cortical bone, which is particularly susceptible to thyroid hormones [1]. Regression analysis showed no correlation between the PBMC z-score and L-T4 dosage, duration of therapy, values of circulating thy roid hormones, plasma levels of TSH and STI, the two latter being considered a good index of tissue hyperthy roidism [8].…”

“…Four more scans at 2-mm intervals were performed distally (DBMC), a site which in adults [7] contains a significant proportion of trabecular bone (30-40%). The bone mineral units generated by the instrument were con verted into grams of bone mineral per centimeter by a conversion factor of 0.0335 and divided by derived cross-sectional area to yield forearm mineral density in g/cm!.…”

Bone Turnover in Overt and Subclinical Hyperthyroidism Due to Autonomous Thyroid Adenoma

“…Furthermore. Taelman et al [12] found no biochemical alterations of bone metabolism, apart from sAP, in premenopausal women with euthyroid goitre treated with moderate doses of thyroid hormones. The results of urinary excretions of 3-hydroxypyridinium de rivatives, pyridinoline and deoxypyridinoline.…”

Bone Changes in Pre- and Postmenopausal Women with Thyroid Cancer on Levothyroxine Therapy: Evolution of Axial and Appendicular Bone Mass

“…Nevertheless, the effect of prolonged subclinical hyperthyroidism on bone mass is controversial [5][6][7]. Cross-sectional studies of bone density in patients on levothyroxine (LT 4 ) suppressive therapy yielded discordant results ranging from unchanged bone mass [8][9][10] to 20-23% reductions in axial and appendicular bone mass [11,12]. Confounding variables such as parathyroid and menopausal status, and also prior history of hyperthyroidism, may be responsible for such differences.…”