Bone Turnover Markers Relations to Postmenopausal OsteoporosisOsteoporosis is a systemic disease characterized by low bone mass and high bone turnover markers in postmenopausal women (PM). The relationship between biochemical bone markers C-telopeptides of type 1 collagen (CTX) and osteocalcin (OC), and bone mineral density (BMD) in the postmenopausal period was examined in 104 PM women divided into three groups according to their BMD: group A - control PM with normal bone density, group B - osteopenic PM and group C - osteoporotic PM. Mean CTX values were highest in group C (0.54±0.24 ng/mL) compared to group B (0.44±0.21 ng/mL) (p<0.0001), and group A (0.33±0.13 ng/mL) (p<0.029). Mean OC levels in group C (26.83±9.91 ng/mL) were significantly higher compared to group A (20.47±7.03 ng/mL) (p<0.011) but not significantly higher compared to group B (24.11±8.38 ng/mL) (p>0.05). Postmenopause duration was longest in group C (13.1±8.31 yrs) compared to group B (9.6±6.24 yrs), and group A (8.15±6.86 yrs). Postmenopausal women developed osteoporosis with longer menopause duration. PM osteoporotic women were characterized by increased levels of bone turnover markers indicating increased rate of bone remodeling, which resulted in excessive bone resorption, and loss of bone mass. Long-term persistence of high bone resorption marker CTX, insufficiently compensated with bone formation marker OC, enabled osteoporosis development.