Osteocalcin Predicts BMD in Postmenopausal Women

OBJECTIVE: To study the relationship between bone markers and bone mineral density (BMD) in an effort to identify their utility in postmenopausal women with osteoporosis.

METHODS: Eighty-two consecutive postmenopausal women with untreated osteoporosis were included in the study. Forearm, spinal, and femoral BMD by dual-energy x-ray absorptiometry and markers of bone formation (serum osteocalcin and bone-specific alkaline phosphatase) and bone resorption (urinary free deoxypyridinoline) were measured in all patients. Patients with low serum vitamin D levels, secondary osteoporosis, or clinically significant systemic disease were excluded from the study. The patients were classified on the basis of BMD of the lumbar spine into the following 3 groups: mild (n = 23) (T score -2.5 through -3), moderate (n = 42) (T score -3.1 through -4), or severe (n = 17) (T score
RESULTS: Serum osteocalcin was significantly different among the 3 study groups (4.1 +/- 2.7, 4.5 +/- 3.1, and 6.7 +/- 5.6 ng/mL, respectively; P = .0349) and had a significant negative correlation with BMD (r2 = -0.0779; P = .0168). Other bone markers such as bone-specific alkaline phosphatase and urinary free deoxypyridinoline did not correlate with the underlying BMD.

CONCLUSION: In our study, osteocalcin was significantly correlated with BMD in postmenopausal women with osteoporosis. Other bone markers did not correlate with BMD. Further large-scale population data and analyses are needed to confirm these findings.