ABSTRACT
Objective: To assess bone turnover status in osteopenic and osteoporotic postmenopausal females
Study Design: Cross-sectional analytical study
Place and Duration of Study: The Aga Khan University Hospital, Karachi, from January to December 2013
Methodology: A cross-sectional study was conducted on 203 postmenopausal females undergoing bone mineral density testing [BMD] by DXA scan. Patients with clinical history of any disorder or medications affecting bone turnover were excluded. Bone turnover was assessed with osteocalcin and beta-CTx. Data was analyzed by SPSS version 19
Results: Mean age of the participants was 54 +/- 4.66 years with a mean BMI of 28.7 +/- 5.5 kg/m2. Mean beta-CTx [0.28 +/- 0.24 ng/ml] and osteocalcin [21.5 +/- 10.6 ng/ml] levels were within the normal reference range. Subjects were grouped into normal [26.6%], osteopenic [44.8%], and osteoporotic [28.6%] based on the t-scores. Serum levels of osteocalcin and beta-CTx between normal, osteopenic, and osteoporotic groups were not significantly different. beta-CTx was negatively and significantly associated with only lumber spine BMD [r = -0.13, p=0.04]. Positive association [< 0.0001] was noted between both markers in normal, osteopenic, and osteoporotic females. However, association of these markers with BMD in the 3 groups were not found. Multivariate linear regression showed a positive and significant effect of BMI on BMD [beta = 0.332, p= < 0.0001]. beta-CTx had negative but significant effect on BMD [beta = -0.155, p= 0.018] of postmenopausal women
Conclusion: Association between baseline levels of BTM and rate of bone loss is variable and site dependent. beta-CTx correlates better with BMD. However, role of osteocalcin in postmenopausal osteoporosis is uncertain and needs further investigation