Longitudinal Changes in Bone Mineral Density and Trabecular Bone Score in Adolescents With Graves' Disease

Longitudinal data on bone health in adolescents with Graves' disease (GD) are limited. Thus, we aimed to evaluate lumbar spine bone mineral density (LSBMD) and trabecular bone score (TBS) changes in this population.

Baseline and follow-up LSBMD Z-score (LSBMD_Z) and TBS Z-score (TBS_Z) were measured. TBS was analysed using iNsight software.

Forty-one adolescents with GD (age 13.7 ± 2.8 years, 73% female) were enroled. At baseline, 18% of adolescents with recently diagnosed GD (RGD, ≤ 6 months) had low LSBMD (median LSBMD_Z: -0.7 [-1.5 to -0.4]), and 58% had low TBS (mean TBS_Z: -1.5 ± 1.3). The median follow-up duration was 2.2 (1.2-2.9) years. In the entire cohort, at follow-up, LSBMD_Z normalized, whereas TBS_Z remained below zero (p = 0.007). Adolescents with RGD and those with longer disease duration had comparable LSBMD_Z and TBS_Z at follow-up. When stratified by baseline disease duration tertiles, improvements in LSBMD_Z (p = 0.013) and TBS_Z (p = 0.035) progressively declined with increasing disease duration. LSBMD_Z was significantly increased from baseline during 28 months of treatment (p = 0.01), while TBS_Z improvement was observed during the initial 9 months (p = 0.046). Stepwise regression identified time-weighted free thyroxine (FT4) as a negative predictor of ∆TBS_Z (p = 0.042).

Low TBS was prevalent among adolescents recently diagnosed with GD. Despite observed improvements, TBS_Z remained below zero at follow-up, indicating incomplete recovery. As FT4 negatively impacts TBS improvement, maintaining optimal FT4 concentrations early in the disease is crucial for preserving bone microarchitecture in paediatric GD.