Influence of thyroid hormones on bone tissue in subclinical and overt hypo- and hyperthyroidism

The prevalence of thyroid disorders continues to increase worldwide, making the study of their systemic effects highly relevant. Thyroid hormones play a crucial role in bone metabolism by regulating the processes of bone remodeling through their effects on osteoblasts and osteoclasts. Both deficiency and excess of thyroid hormones may disrupt the balance between bone formation and bone resorption, thereby contributing to decreased bone mineral density and increased fracture risk. Subclinical forms of hypothyroidism and hyperthyroidism are of particular clinical interest, as metabolic alterations in bone tissue may develop even in the absence of overt clinical manifestations.

The aim of this study was to evaluate the influence of thyroid hormones on bone tissue in patients with subclinical and overt hypo- and hyperthyroidism by assessing bone metabolism markers and bone mineral density.

The study included 120 patients aged 25–65 years who underwent examination and treatment at the Republican Specialized Scientific and Practical Medical Center of Endocrinology named after Academician Yo. Kh. Turakulov, Tashkent, Uzbekistan. Patients were divided into four groups: subclinical hypothyroidism, overt hypothyroidism, subclinical hyperthyroidism, and overt hyperthyroidism, with 30 patients in each group. The control group consisted of 30 euthyroid healthy individuals matched by age and sex. Serum levels of thyroid-stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), osteocalcin, β-C-terminal telopeptide of type I collagen (β-CTx), bone-specific alkaline phosphatase, parathyroid hormone, and vitamin D were determined using enzyme-linked immunosorbent assay methods. Bone mineral density was assessed by dual-energy X-ray absorptiometry (DXA) at the lumbar spine (L1–L4) and femoral neck. Statistical analysis was performed using SPSS Statistics 26.0.