骨代谢生化指标与女性年龄及骨密度的相关性

Correlation between age-related changes of osseous metabolic markers and bone mineral density in females

目的：探讨女性骨代谢生化指标与年龄及骨密度的关系。方法选取不同年龄组女性309例（25～84岁），以电化学发光法检测患者血清总Ⅰ型胶原氨基端延长肽（ TPⅠNP ）、β胶原特殊序列（β.CTX）的含量，ELISA检测患者血清25.羟基维生素D（25-OH-VitD）、抗酒石酸酸性磷酸酶5b（TRACP-5b），采用双能X线（DXA）骨密度仪测其股骨颈及腰椎L1～4部位的骨密度（BMD）。将309例患者根据年龄和BMD进行分组，比较组间骨代谢生化指标差异，采用SPSS 17.0软件对数据进行两样本t检验、方差分析或χ2检验。结果血清TPⅠNP、β-CTX在45～54岁组高于在35～44岁组：（55.63±19.24）比（40.90±14.63）μg／L，（597.10±198.70）比（404.79±147.22） ng／L（t＝4.156、5.319，均P＜0.01），随后随年龄增长呈下降趋势；血清25-OH-VitD 随年龄增长呈下降趋势；血清TRACP.5b在45～54岁组高于在35～44岁组（t＝5.934，P＜0.01），55～64岁组进一步升高至（5.05±1.63） U／L，后随年龄增长呈下降趋势。骨量减少组（100例）和骨质疏松组（111例）血清TPⅠNP、β.CTX、25-OH-VitD、TRACP.5b与骨量正常组（98例）相比差异均具有统计学意义（ F＝225.908、253.208、252.927、313.265，均P＜0.01）。以BMD结果为“金标准”，4项骨生化指标对于BMD异常的诊断特异性和阳性预测值均大于95％，血清25.OH.VitD、TRACP.5b的灵敏度[91.47％（193／211）、88.15％（186／211）]高于血清TPⅠNP[65.40％（138／211）；χ2＝42.381、30.621，均P＜0.01]和β-CTX的灵敏度[51.66％（109／211）；χ2＝82.164、66.783，均P＜0.01]。阴性预测值的比较亦有类似结果（χ2：15.367～38.126，均P＜0.01）。结论女性骨代谢生化指标均与年龄及BMD存在密切相关性，检测骨代谢生化指标在早期诊断骨质疏松中非常重要。

Objective To investigate the age-related changes of osseous metabolic markers and their relationships to bone mineral density （ BMD） in females. Methods A total of 309 females with differ.ent ages （25-84 years） were enrolled. The total collagen type I amino-terminal extension peptide （TPⅠNP） and beta collagen specific sequences （β-CTX） were measured by electrochemical luminescence method. 25-hydroxy vitamin D（ 25-OH-VitD） and tartrate.resistant acid phosphatase.5b（ TRACP-5b） were measured u.sing ELISA. BMD of femoral neck, lumbar spine 1-4 were measured with a bone densitometer （ GE Lunar Prodigy dual energy X-ray absorptiometry, DXA）. The differences among different age and BMD groups were compared by two.sample t test, one.way analysis of variance,χ2 test with SPSS 17.0 software. Results The serum TPⅠNP , β-CTXlevels in the 45-54 years group were higher than those in the 35-44 years group：（55.63±19.24） μg/L vs （40.90±14.63） μg/L, （597.10±198.70） ng/L vs （404.79±147.22） ng/L （ t=4.156, 5.319, both P〈0.01） , and decreased slightly with increasing age. The serum 25-OH-VitD level decreased with increasing age. The serum TRACP-5b in the 45-54 years group increased significantly com. pared to that in the 35-44 years group （t=5.934,P〈0.01）; and it reached the highest level of （5.05± 1.63） U/L in the 55-64 years group, then decreased slightly. The serum levels of TPⅠNP,β-CTX,25-OH-VitD,TRACP-5b in osteopenic and osteoporosis groups were significantly different from those in the nor.mal group （ F=225.908, 253.208, 252.927, 313.265, all P〈0.01） . The specificities and positive predic-tive values of all four osseous metabolic markers were all over 95% for the diagnosis of abnormal BMD. The sensitivities of both serum 25-OH-VitD and TRACP-5b levels were higher than those of TPⅠNP （ 91. 47%（193/211）, 88.15%（186/211） vs 65.40%（138/211）; χ2=42.381, 30.621, both P〈0.01） and β-CTX（51.66%（109/211）; χ2=82.164, 66.783, both P〈0.01）. Negative predictive values of both serum 25-OH-VitD and TRACP-5b levels were higher than those of TPⅠNP（χ2=23.103, 15.367, both P〈0.01） andβ-CTXχ2=38.126, 28.514, both P〈0.01） . Conclusions The osseous metabolic markers might be close-ly related to the changes of BMD and age in females. It was important to measure the bone metabolism mark.ers in the early diagnosis of osteoporosis.