男性骨生化指标随年龄的变化及其与骨密度的关系

Biochemical markers of age-related changes in bones turnover and bone mineral density in healthy Chinese men

目的:探讨男性人群血清骨特异性碱性磷酸酶(BAP)和Ⅰ型胶原氨基末端肽(NTX)随年龄变化及其与骨密度(BMD)之间的关系。方法:用ELISA测定389例20～80岁健康男性BAP和NTX,用DXA仪测定腰椎及髋部BMD。结果:BAP和NTX与年龄呈负相关,随年龄的变化均以三次回归模型的拟合程度最佳,拟合曲线的决定系数(R2)为0.013～0.029(P<0.05)。2个生化指标的水平在20～29岁年龄段最高,随后随年龄的增长而降低;50～59岁段达最低值。60岁之后骨吸收指标轻度增加,而骨形成指标则保持相对稳定。校正年龄、身高、体质量、体质量指数及吸烟后的偏相关分析显示BAP与各部位BMD呈负相关,而NTX与腰椎及髋部总体BMD呈负相关。结论:BAP和NTX是反映中国男性随年龄变化的骨转换的敏感性、特异性较强的指标,监测这两个指标有助于早期防治骨质疏松症(OP)。

Objective To determine the relationship between bone alkaline phosphatase （ BAP ） and cross-linked N-telopeptides of type Ⅰ collegen （ NTX ） and bone mineral density in healthy men aged 20 -80. Methods BAP and NTX of 389 healthy men were measured by ELISA. BMD at the lumbar spine and the hip as measured by dual energy X-ray absorptiometry. The correlation of bone biochemical markers with age and BMD fit 10 regression models. Results BAP and NTX negatively correlated with age. The cubic regression model was better with age-related changes of bone biochemical markers as compared with the other regression models and the coefficients of determination of fitting curve were 0. 013 -0. 029 （P 〈0.05 ）. The value of bone biochemical markers as the highest during 20 -29 age groups, then they decreased to a nadir level in the 50 -59 years age. After 60 years, bone formation markers remained stable; however resorption marker increased slightly. After adjustment for age, weight, height, BMI, and smoking, bone biochemical markers were negatively correlated with most sites of BMD. Conclusion BAP and NTX may be relatively sensitive and specific markers to evaluate age-related changes of bone turnover. It may benefit the prevention of osteoporosis by monitoring the level of BAP and NTX.