Effects of Levothyroxine and thyroid stimulating hormone on bone loss in patients with primary hypothyroidism

Abstract

Objective:Previous studies on bone mineral density (BMD) abnormalities associated with hypothyroidism are scarce and not conclusive. The effect of thyroid hormone therapy on BMD has shown mixed results. The aim of the present study was to determine the severities of osteoporosis in female patients with hypothyroidism in comparison to healthy women.Methods:This cross-sectional descriptive study was performed on 150 women aged over 50 years. Totally, 100 patients with primary hypothyroidism and 50 healthy subjects were enrolled in this study and divided into three groups. Group A, which consisted the patients who had been recently diagnosed with primary hypothyroidism. The second group of patients diagnosed with primary hypothyroidism for at least 2 years and was treated with levothyroxine (Group B). The third group of healthy individuals was selected as a control group (Group C). Blood samples were taken for the measurements of thyroid stimulating hormone (TSH), and bone densitometry was performed to determine the BMD reported as T-score in order to measure the severity of osteoporosis. T-score of the lumbar vertebra (L2-L4) and femoral neck were measured with dual energy X-ray absorptiometry and were compared between the three groups. Data were analyzed by SPSS using regression analysis and Mann–Whitney, Kruskal–Wallis, or analysis of variances statistical tests. The statistical significance was set at a P < 0.05.Findings:The average age of patients and baseline serum TSH levels in Group B was significantly different from the other two groups (P < 0.001). T-score of the lumbar spine (L2-L4) in Group B was significantly lower than the other groups (P = 0.01). The linear regression between serum TSH levels and BMD categories were not clearly associated. However, after removing the effect of the baseline TSH level in Group B, bone loss was significantly greater than the other two groups (P = 0.01).Conclusion:According to the present study, it seems that the treatment of hypothyroidism with thyroid hormones reduces both serum levels of TSH and bone density. Hence, proper control of this risk factor can be an effective way in prevention of osteoporosis.

MECHANISMS IN ENDOCRINOLOGY: Impact of isolated TSH levels in and out of normal range on different tissues

“…Another observation also supports the lack of physiological replacement by exogenous T 4 . When TSH levels in patients with SCH were lowered by L-T 4 treatment, normal bone structure could not be restored (82). TSH suppression for TC showed similar results as TSH suppression for SH and was accompanied by increased bone resorption in postmenopausal women (83).…”

Hypothyroidism due to Hashimoto's thyroiditis masked by anorexia nervosa

“…21 It is thought to be due to the Wolff-Chiakoff, effect an autoregulatory mechanism that is not completely understood but essentially excess iodine inhibits the availability of the active organic form of iodide and thus the production of thyroid hormones. [31][32][33][34] To our knowledge, there are no published reports of Hashimoto's thyroiditis in AN. It is possible that during periods of weight gain our patient's diet may have consisted of enough additional iodine to further suppress thyroid function given her innate susceptibility due to Hashimoto's thyroiditis.…”

“…Although recent studies question the degree of bone loss with thryroid supplemenation the initiation of L-T 4 must be carefully considered. [31][32][33][34] To our knowledge, there are no published reports of Hashimoto's thyroiditis in AN. With few case studies of elevated TSH or autoimmune thyroid disease in the setting of AN, this report and additional studies will better guide the management of such patients.…”

The Prevalence of Fragility Fractures in a Population of a Region of Southern Italy Affected by Thyroid Disorders

“…In the literature, it is reported that, in the presence of high values of TSH (condition of hypothyroidism) or in cases of suppressed TSH (condition of hypothyroidism in treatment), there is an increased risk of fragility fractures [29]. From the data of our study, in consideration of the differences, in terms of increased incidence of fragility fractures in patients with clinical hypothyroidism compared to subclinical, we highlight the importance of the role of hormone replacement therapy.…”