Effect of Thyroid-Stimulating Hormone Suppression on Bone Mineral Density in Patients with Differentiated Thyroid Carcinoma: A Single Center Retrospective Study.

Background: This study evaluated the correlation between the degree and duration of thyroid-stimulating hormone (TSH) suppression and changes in bone mineral density (BMD) in patients who underwent surgery for differentiated thyroid carcinoma (DTC).

Methods: We included 65 women who underwent surgery for DTC and had at least two BMD measurements. Changes in BMD were statistically analyzed with a focus on postmenopausal women.

Results: The mean patient age was 52.2 years. During the follow-up period, 10 patients (15.4%) received osteoporosis treatment, and six (9.2%) experienced fractures. Analysis of 50 postmenopausal women revealed significant decreases in lumbar spine BMD (P=0.007), femoral neck BMD (P=0.008), and total hip BMD (P=0.010). Patients with TSH suppression <0.5 mU/L exhibited a 1.24%/y decrease in lumbar spine BMD, showing a marked reduction compared to a 0.33%/y decrease in BMD in the group with TSH ≥0.5 mU/L (P=0.025). Linear regression analysis comparing the duration of TSH suppression revealed a significant correlation with lumbar spine BMD (P<0.001). However, no correlation was observed between TSH suppression and decreased femoral neck BMD. Although not significant, the reduction in BMD in the lumbar spine was greater in the calcium and vitamin D non-supplementation group than in the supplementation group (1.31%/y vs. 0.71%/y; P=0.349).

Conclusions: Prolonged aggressive TSH suppression significantly affects lumbar spine BMD in patients with DTC. These findings highlight the need to balance TSH suppression with the risk of bone health deterioration, particularly in postmenopausal women.