Association of impaired sensitivity to thyroid hormone with low bone mineral density and bone mineral content.

Osteoporosis is a systemic condition characterized by reduced bone mineral density (BMD) and bone mineral content (BMC), with its global prevalence increasing annually. Thyroid hormone (TH), as well as the sensitivity of central and peripheral target tissues to TH, play a regulatory role in bone health. This review examines traditional thyroid function indicators and thyroid hormone sensitivity indices, systematically evaluating their effects on BMD and BMC of different skeletal sites. Changed sensitivity of central and peripheral tissues to THs lead to distinct regulatory effects on bone mass. Sensitivity indices exhibit less variability and offer a more comprehensive reflection of thyroid hormone homeostasis, providing a more nuanced understanding of the complex relationship between fluctuations in thyroid hormone levels and decreased BMD at osteoporosis-prone sites, such as the vertebrae and femoral neck. This paper reviewed the relationship of classical thyroid function parameters, as well as central and peripheral thyroid hormone sensitivity indices, with decreased bone mass at osteoporosis-prone sites. While numerous published studies have supported an association between altered central and peripheral thyroid hormone sensitivity and reduced bone mass, inconsistencies remain in the literature. Further large-scale, high-quality randomized controlled trials (RCTs) are warranted to clarify the causal relationship between these factors.