Diagnostic value of circulating bone turnover markers osteocalcin, cathepsin K, and osteoprotegerin for osteoporosis in middle-aged and elderly postmenopausal women

The most common disease among elderly patients is osteoporosis (OP), a bone disease caused by reduced bone strength and increased risk of fractures [1].Postmenopausal osteoporosis (PMOP) is prevalent in women and is characterized by the systemic impairment of bone mass and microarchitecture.The cause of OP has not yet been fully elucidated, and many risk factors are associated with the disease, including reduced bone mass, hormonal imbalance, use of certain drugs (such as glucocorticoids), smoking, low physical activity, and insufficient intake of calcium and vitamin D [2].Radiologic laboratory assessments (dual-energy X-ray absorptiometry (DEXA)) of bone mineral density (BMD) can accurately diagnose OP before a fracture occurs.However, DEXA scanning is costly and requires specialized equipment and trained staff [3].Studies have shown that the change in levels of bone turnover markers (BTM) often precedes BMD and may be detected a few months after anti-OP treatment, providing valuable information regarding the diagnosis of OP and efficacy of treatment [4].Investigations using osteoporotic serum have suggested several biomarkers for bone resorption and formation that are related to BMD.The estrogen receptor (ER) gene, vitamin D receptor VDR gene, interleukin-6 (IL-6), bone sialoprotein, procollagen type I N propeptide (PINP), and microRNAs have been investigated for their impact on BMD and their use in the diagnosis of OP [5][6][7].Although BTMs, osteocalcin (OCN), cathepsin K (Cat K), and osteoprotegerin (OPG), have been shown to play important roles in bone metabolism [8-10], it is not clear whether these markers can be used to accurately predict primary PMOP in middle-aged and elderly postmenopausal women.In this study, we measured serum levels of OCN, Cat K, and OPG in middle-aged and elderly postmenopausal women and assessed the diagnostic value of these markers for PMOP to develop alternative tools for the prevention and treatment of OP-related fragility fractures.Methods.Women who participated in a regular OP screening program at our hospital between February 2020 and March 2022 were selected for this study.The participants were grouped into control (non-OP), osteopenia (BMD T-scores -2.5 to -1.0), and OP (T-scores (< -2.5) groups [11].The participants were included if they had menopause for at least 1 year and were aged between 50 and 75 years.Participants were excluded if they had fractures, ma-