OBJECTIVE: To evaluate whether thyroid stimulating hormone-suppressive thyroxine replacement therapy increases bone loss in postmenopausal women. MATERIALS AND METHOD: The study had a cross-sectional design. Fifty-four postmenopausal women on long-term treatment with thyroxine for primary hypothyroidism, who showed suppressed thyroid stimulating hormone levels were enrolled in our study. In these patients and in a control group of 54 healthy postmenopausal women we evaluated bone mineral density at distal radius and the main biochemical parameters of bone turnover. Student's t test, Wilcoxon signed rank-test, Chi-square test and the univariate linear regression in the statistical analysis of the data were employed. RESULTS: Bone mineral density values, expressed as z-scores, in the treated group were significantly decreased in comparison with the control group (p < 0.01). We did not detect a significant relationship between different L-thyroxine doses administered and bone mineral density z-scores. On the contrary, an inverse correlation was detected between length of treatment and bone mineral density z-scores. Treated patients showed a significantly higher concentration of serum alkaline phosphatase, osteocalcin, urinary calcium/creatinine and hydroxyproline/creatinine in comparison with the controls. CONCLUSIONS: Our study suggests that thyroxine replacement therapy in patients with suppressed thyroid stimulating hormone levels increases postmenopausal bone loss.
Effects of thyroxine therapy on bone metabolism in postmenopausal women with hypothyroidism / Affinito, P; Sorrentino, C; Farace, Mj; di Carlo, C; Moccia, G; Canciello, P; Palomba, S; Nappi, C.. - In: ACTA OBSTETRICIA ET GYNECOLOGICA SCANDINAVICA. - ISSN 0001-6349. - 75:9(1996), pp. 843-848. [10.3109/00016349609054714]