Estimation of serum osteocalcin and telopeptide-C in postmenopausal osteoporotic females

Abstract

A negative correlation of serum C-terminal telopeptide of type I collagen (telopeptide-C) was observed with bone mass density (BMD) in postmenopausal control (r = -0.70, p < 0.05) and osteoporotic females (r = -0.46, p < 0.05) indicating increased bone resorption in these subjects. Since telopeptide-C is a significant determinant of bone loss, it can be used, in combination with bone mass measurement, for the assessment of postmenopausal females. The aim of this study was to find out the significance of serum osteocalcin, a marker of bone formation, and C-terminal telopeptide of type I collagen, a marker of bone resorption, in evaluating osteoporotic patients and to find out their relationship with bone mass density. One hundred and fifty (150) females; 50 premenopausal (age=31.13 +/- 1.29), 50 postmenopausal (age = 54.36 +/- 0.81) and 50 postmenopausal osteoporotic patients (age = 58.6 +/- 0.701) were included in this study. The postmenopausal subjects, with and without osteoporosis, were selected from different osteoporotic clinics and healthy premenopausal females were selected from general population. Height, weight, BMI, waist/hip ratio, age at menarche, years since menopause in case of postmenopausal women, history of disease, and fracture, if any, were recorded. BMD assessment was done on calcaneous by peripheral ultrasound bone densitometery on Sahara Clinical Bone Sonometer and T-scores were calculated. Serum levels of osteocalcin and C-terminal telopeptide of type I collagen and calcium were measured. A lower BMD in postmenopausal subjects, with and without osteoporosis (p < 0.001), indicating increased bone loss with aging and menopause, was observed. A negative correlation was found between age and BMD (r = -0.67, p < 0.05). No correlation was found between osteocalcin and BMD among these groups, suggesting heterogeneity of osteocalcin fragments in serum that limits its significance in the evaluation of osteoporosis. A positive correlation was found between osteocalcin and telopeptide-C (r = 0.26, p < 0.05). A positive correlation of telopeptide-C with age (r = 0.45, p < 0.05) and a negative correlation with BMD (r = -0.46, p < 0.05) was observed indicating increased bone resorption in postmenopausal control and postmenopausal osteoporotic patients. C-terminal telopeptide of type I collagen appears to be a significant determinant of bone loss and may be used as a valuable tool in the assessment of postmenopausal osteoporotic patients.