Elevated serum osteocalcin levels as a surrogate marker of primary osteoporosis in postmenopausal women

Abstract

Background: Primary osteoporosis is increasingly becoming a major public health concern in African populations. Complications arising from this condition can be catastrophic; ranging from hip fractures to lumbar spinal injuries. Early diagnosis and prevention are useful in mitigating its effects. The Dual Energy X-ray Absorptiometry (DXA) scan is not a widely affordable and accessible diagnostic tool to many in our setting. There is need for an alternative, affordable and accessible marker for early screening of osteoporosis.

Objective: To correlate serum osteocalcin level with DXA findings in the diagnosis of osteoporosis in postmenopausal women.

Design: This was an analytical cross-sectional study.

Setting: Orthopaedic outpatient clinic of the Kenyatta national Hospital.

Participants: 61 postmenopausal women aged 50 years and above were assessed for both neck of femur and lumbar vertebrae DXA bone mineral density and serum osteocalcin levels.

Results: Twenty-eight (46%), 11 (18%) and 22 (36%) women had normal, osteoporotic and osteopenic bone mineral density levels respectively. Serum Osteocalcin levels for normal, osteopenic and osteoporotic groups was 12.51±2.5 ng/ml, 22.14±5ng/ml and 31.46±8ng/ml respectively (p=0.00). There was a negative correlation between osteocalcin levels and DXA femoral neck bone mineral density (Coefficient – 0.68, P = 0.00). Women with Osteoporosis (T-score ≤ -2.5 SD) consistently had osteocalcin levels of ≥ 25.1 ng/ml.

Conclusion: Serum Osteocalcin levels are predictive of DXA findings and elevated levels can be considered as a surrogate marker of primary osteoporosis in postmenopausal women.