老年女性腰椎骨折后骨密度及骨代谢指标的动态变化

Dynamic alterations of bone mineral density and bone metabolism indices in elderly women after lumbar vertebra fracture

【摘要】目的 研究老年女性腰椎骨折愈合后（伤后6～12个月）骨密度及骨代谢指标的变化情况，并探讨其相关性，为骨代谢指标的临床应用提供理论依据，有效预防二次骨折。方法 按纳入及排除标准选取因腰椎骨折就诊的老年女性48人。制定随访标准于伤后4h，3d，6个月，12个月进行伤椎、健椎、双髋骨密度测量，及骨代谢指标水平的测定：骨碱性磷酸酶（BAP）、骨γ-羧基谷氨酸蛋白（骨钙素，osteocalcin，BGP）、Ⅰ型胶原羧基（C）端交联肽（CTX-Ⅰ）、血清抗酒石酸酸性磷酸酶5b（TRACP5b）。骨折后4，6个月行CT+三维重建了解骨折愈合情况。采用SPSS17.0统计学软件对数据进行分析和处理。结果 患者骨折愈合后，伤椎及健椎骨密度显著低于基线值（P＜0.01），双髋部位骨密度与基线值差异无统计学意义。患者在伤后6个月，骨代谢指标BAP，BGP，CTX-Ⅰ，TRACP5b水平均显著高于基线值（P＜0.05）。患者在伤后12个月，即骨折完全愈合6个月，BGP水平显著高于基线值（P＜0.01），其余骨代谢指标与基线值差异无显著性意义。骨折达到临床及影像学愈合后，血清BGP水平的改变量与伤椎骨密度改变量的偏回归系数最大。结论 骨折达到临床愈合后，血清BGP水平对于评估骨密度回升速度具有较高价值。骨折愈合后监测相应的骨代谢指标可以提高判断骨密度变化的准确性，以降低罹患二次骨折的风险。

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【Abstract】Objective To observe the changes in bone mineral density (BMD) and bone metabolism indices in the elderly women in 6 to 12 months after lumbar vertebra fracture, and investigate their correlations so as to provide theoretical basis for the clinical application of bone metabolism indices to effectively prevent secondary fracture. Methods Forty-eight elderly women meeting our inclusion and exclusion criteria of lumbar vertebra fracture were recruited in this study. The standards for follow-up were set up to measure the BMD in the fractured vertebra, healthy vertebra and the hips in 3d, and 6 and 12 months after fracture, and to determine the serum levels of bone metabolism indices, including bone alkaline phosphatase (BAP), bone γ-carboxyglutamic acid containing proteins (BGP, osteocalcin), carboxy-terminal cross-linking telopeptide of type Ⅰ collagen (CTX-Ⅰ) and tartrate-resistant acid phosphatase 5b (TRACP5b) in 4h (as baseline), 3d, 6 and 12 months after fracture. CT scanning was used to evaluate the bone healing in 4 and 6 months after fracture. All the data were recorded, analyzed and processed with SPSS 17.0 statistical software. Results After fracture healing, the BMD value was significantly lower than the baseline value in the fractured and healthy vertebra (P＜0.01), and not statistically different with baseline value in the hips. In 6 months after fracture, the serum levels of BAP, BGP, CTX-Ⅰ and TRACP5b were significantly higher than the baseline values (P＜0.05). In 12 months after fracture, namely 6 months after fracture healing, the serum level of BGP was obviously higher than the baseline value (P＜0.01), while the other indices of bone metabolism showed no statistical difference with the baseline values. When the fracture healing reached the clinical and radiographic standards, the partial regression coefficient of delta-Zscore was maximal between the change in serum BGP level and the change in BMD of the fractured vertebra. Conclusion When the fracture reaching clinical healing, the serum level of BGP is of great value in the assessment of recovering speed of BMD. Monitoring corresponding bone metabolism indices after fracture healing improves the accuracy of judging BMD changes and reduces the risk of secondary fractures.