[Serum osteoprotegrin and serum bone gamma-carboxyglutamine acid-containing protein are correlated with bone mineral density in normal women].

Objective: To study the relationships of serum osteoprotegrin (sOPG), serum bone gamma-carboxyglutamine acid-containing protein (sBGP), and urine deoxypyridinoline (uDPD)/creatinine (Cr) with age and bone mineral density (BMD) in women.
Methods: ELISA was used to examine the sOPG, sBGP, and uDPD/Cr of 672 female volunteers aged 20-80. The BMD (QDR4500A) value of the anteroposterior lumbar spine and femoral neck were measured by DXA.
Results: (1) The levels of sOPG, sBGP, and uDPD/Cr in the age group of 30-39 were 2.8 pmol/L +/- 1.4 pmol/L, 5 microg/L +/- 3 microg/L, and 4.9 nmol/mmol +/- 2.5 nmol/mmol respectively, all significantly lower than those in the age groups 40-49, 50-59, and 60-69 (all P < 0.05). (2) In the age group 40-49, the values of sOPG, sBGP, and uDPD in menopausal subjects were significantly higher than those of the non-menopausal subjects (5.7 pmol/L +/- 3.1 pmol/L vs 3.4 pmol/L +/- 2.0 pmol/L, 11 microg/L +/- 5 microg/L vs 6 microg/L +/- 3 microg/L, and 6.9 nmol/mmol +/- 3.3 nmol/mmol vs 5.2 nmol/mmol +/- 3.9 nmol/mmol, all P < 0.001). (3) Age was positively correlated with sOPG, sBGP, uDPD/Cr, and BMD of anteroposterior lumbar spine and femoral neck (r = 0.130, 0.355, 0.106, -0.600, -0.545; P < 0.01). sOPG and sBGP were negatively correlated to anteroposterior lumbar spine BMD (r = -0.183, -0.108, P < 0.01; and r = -0.541, -0.441, P < 0.001). sOPG was positively correlated with sBGP and uDPD/Cr (r = 0.216 and 0.083; both P < 0.05).
Conclusion: sOPG, sBGP, and uDPD/Cr can be used as sensitive markers to determine the bone turnover status, which is changeable with age, and menopausal status in women, and predict the bone lose prior to BMD determination by DXA.