Estrogen deficiency found in postmenopausal women may lead to disturbances in the balance of bone metabolism. Study of the influence of estradiol on markers of bone turnover may help to understand the mechanisms of bone metabolism and to monitor osteoporosis therapy in postmenopausal women at high risk of fractures. The aim of the study was evaluation of the effect of estradiol on the basic markers of bone turnover in postmenopausal women.

Material and methods:
The study was conducted in a group of 92 postmenopausal women, divided into two groups: Gr-1 with low estradiol levels ≤ 10 pg/ml and Gr-2 with reference estradiol levels ≥ 25 pg/ml). Basic markers of bone turnover were examined: Ctx (C-terminal cross-linked telopeptide of type I collagen alpha chain) and OC (osteocalcin); pro-resorptive cytokines: IL-6 and TNF-α; vitamin 25(OH)D3 and lipid profile. Women was also analyzed according to demographic and clinical data.

A positive relationship was found between estradiol and the main bone formation marker – OC (p = 0.041, r = 0.213) and IL-6, TNF-α (p = 0.007, r = 0.281 and p = 0.018, r = 0.246, respectivly, but only in the group with a reference hormone level. Moreover, the main markers of bone turnover: Ctx and OC showed a mutual positive correlation (p = 0.013; r = 0.257) in women with reference estradiol levels. Relationships between markers of bone remodeling, pro-resorptive cytokines and vitamin D3 depending on the level of estradiol showed no statistically significant correlation.

The study showed that only in women with the reference estradiol level (≥ 25 pg/ml) were the bone formation and resorption processes balanced.

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