Serum Osteocalcin and Bone Mineral Density as Markers of Post-menopausal Osteoporosis: A Meta-analysis

Osteocalcin (OC) and bone mineral density (BMD) measurements determine the bone mass and microarchitecture of bone. Both are used for diagnosing osteoporosis and their role as a biomarker in postmenopausal osteoporosis (PMO) remains controversial. To determine the relationship between serum OC and PMO and compare BMD vs OC, a metaanalysis was carried forward with case-control studies. Studies reporting mean/median and standard deviation of osteocalcin in post-menopausal women with and without osteoporosis were included. From the same studies, BMD measurements in both groups were included. Fifteen studies were included with 1864 postmenopausal women. We found significant increase in serum OC (Standardized Mean Difference of 0.918 and SE of 0.476 (p=0.054), confidence interval (CI) (-0.015 to 1.852) and significant decrease in BMD values (SMD of -2.321 and SE of 0.345 (p= <0.001) (CI - 2.998 to -1.643)) in PMO. T score also significantly decreased in PMO (SMD <0 (-3.785). Heterogeneity was observed in all parameters analyzed for more than 90%. We concluded that in our metanalysis, there was a significant increase in serum osteocalcin levels with SMD> 0 and significantly low BMD/t score levels with SMD <0 in postmenopausal osteoporotic women as compared to healthy postmenopausal women. Osteocalcin gives the current status of bone remodeling and is not influenced by multiple factors whereas BMD measures the bone mass, yet techniques vary and are influenced by many factors. SMD < 0 alone cannot be used to detect osteoporosis or predict osteoporotic fractures. Increased osteocalcin and low BMD/T score after menopause together are good indicators to detect osteoporosis. This conjunction can economically burden the patient and thus our study concludes that SMD > 0 serum osteocalcin solely can be implemented as a promising marker for diagnosing osteoporosis.