Validity of Osteocalcin and Alkaline Phosphatase Biomarkers in Postmenopausal Women With Low Bone Mineral Density

Abstract

Background: Bone mineral density (BMD) can predict osteoporotic fractures which are major public health problem associated with increased morbidity, mortality, and health care cost amongst elderly.

Objective: To assess validity of osteocalcin and alkaline phosphatase (ALP) biomarkers in postmenopausal women with low bone mineral density (BMD)

Patients and Methods: This cross sectional study was conducted on postmenopausal women. BMD was measured by Dual energy x-ray absorptiometry (DEXA). Salivary and serum of both osteocalcin and alkaline phosphatase were measured from all postmenopausal women.

Results: Of a total 72 postmenopausal women, 48 had low BMD and 24 of normal BMD. Mean salivary and serum osteocalcin and mean serum alkaline phosphatase (ALP) levels were significantly higher in postmenopausal women with low BMD than those of normal BMD. Mean salivary ALP level was numerically more in women with low BMD than those with normal BMD but statistically not significant. Salivary and serum osteocalcin and ALP biomarkers score at cut off >1 had accuracy of 80.55 % to diagnose postmenopausal women with low BMD with positive predictive value of 88.64 %, sensitivity was 81.25 %, and specificity 79.17%.

Conclusions: Osteocalcin and ALP were valid biomarkers to diagnose postmenopausal women with low BMD. Biomarker score>1 had high accuracy and sensitivity to diagnose low BMD. This may suggest a new promising measure to early diagnose patients at high risk of low BMD and subsequently giving early appropriate treatment.

Key words: Osteocalcin, Alkaline phosphatase, bone mineral density, periodontal status