Relationship between Estradiol and Bone Biomarkers in the Longevity Females

Background: Bone turnover markers (BTMs) are modulated by serum estradiol (E2) which is crucial for maintaining the health and physical function of bone in older adults. However, data on the levels and epidemiological distributions of serum BTMs and E2 among older postmenopausal women (such as female centenarians) are limited. This study was aimed to investigate the relationship between BTMs and E2 in the older postmenopausal women.Methods: A total of 456 female centenarians were included, and their serum concentrations of BTMs (including phosphorus, calcium, 25-hydroxyvitamin D [25(OH)D], parathyroid hormone [PTH], total type I procollagen amino-terminal peptide [total PINP], beta-isomerized C-terminal telopeptides [beta-CTX], alkaline phosphatase [ALP], and osteocalcin [OC]) and E2 were assessed. Linear regression models were used to examine the relationship between BTMs and E2. Multivariate regression models were fitted, along with subgroup analysis and robustness tests.Results: The median levels with interquartile ranges of serum E2, ALP, phosphorus, calcium, OC, beta-CTX, total PINP, PTH, and 25(OH)D were 46.8 (33.9, 70.90), 83.0 (68.0, 105.0), 1.07 (0.97, 1.17), 2.19 (2.11, 2.28), 32.43 (21.62, 44.60), 0.45 (0.30, 0.63), 71.0 (51.0, 97.3), 47.4 (34.7, 65.5), and 19.6 (14.3, 24.4), respectively. A higher E2 level was related to increased beta-CTX (0.15 [0.10, 0.20]), total PINP (0.18 [0.10, 0.26]), and PTH (0.075 [0.022, 0.128]) levels in the fully adjusted model. We also found that a higher E2 level was associated with decreased levels of 25(OH)D (-0.35 (-0.51, -0.19)) and calcium (-0.60 [-0.80, -0.40]) among female centenarians (p < 0.001).Conclusions: Among centenarian women, bone formation markers (serum calcium and 25[OH]D) were negatively correlated with E2 level, while bone resorption marker (beta-CTX) was positively correlation with E2 level.