Evaluation of Osteopontin in Combination with Bone Turnover Markers for the Assessment of Osteoporosis in Postmenopausal Women

Aims: Osteoporosis, a disease characterized by low bone mass and microarchitectural deterioration of bone tissue, has an important impact on the lives of postmenopausal women, owing to the increased risk of fractures. Although bone mineral density (BMD) is the standard criteria used for the diagnosis of osteoporosis, but BMD provides a slow and static picture of skeleton whereas, the biochemical markers of bone turnover (BTM) can provide dynamic status of bone remodeling and rapid measurement of skeletal metabolism. Osteopontin (OPN), a glycoprotein has been implicated in bone remodeling by activating the resorption process. Combination of osteopontin with classical bone turnover markers can enhance the confidence of detecting osteoporosis and predicting fracture risk.

Study Design: Cross-sectional study.

Place and Duration of Study: Department of Pathology, Quaid-e-Azam Medical College, Pakistan from 1st July 2015 to 15th September 2015.

Methodology: We included 120 females (60 postmenopausal, age >45 years and 60 from childbearing age 25-45 years) and excluded all conditions affecting bone metabolism. Enzyme-linked immunosorbent assay technique was used to measure levels of bone markers in serum.

Results: Bone markers were significantly higher in postmenopausal group of patients. Osteopontin was found to be positively correlated with osteocalcin (r=0.82), bALP (r=0.76), CTX (r=0.62) and DPD (r=0.49) and it was negatively correlated with BMD lumbar spine (r= -0.71) indicating a significant correlation (p<0.0001). The osteopontin and osteocalcin combination showed highest sensitivity (94%) and specificity (88%), closely followed by that of osteopontin and bone alkaline phosphatase combination.

Conclusion: High levels of osteopontin in postmenopausal women are associated with low BMD, raised levels of bone turnover markers and fractures. When used in combination with other bone turnover markers, it can provide an accurate assessment of osteoporosis and fracture risk.