Abstract: Objective　To investigate the association between N-terminal osteocalcin (N-MID) and osteoporosis in elderly male patients with type 2 diabetes mellitus (T2DM). Methods　The clinical data of 100 male T2DM outpatients or inpatients ≥60 years old who were treated in Dezhou People's Hospital from January 2015 to December 2019 were retrospectively analyzed. They were divided into a non-osteoporotic group (62 cases) and an osteoporotic group (38 cases) according to their bone mineral densities (BMD). The BMD was measured in all the patients, and the serum levels of leptin, 25(OH)D3, bone alkaline phosphatase (BAP), procollagen type I ca rboxy-terminal peptide (PICP), pyridinoline cross linked carboxyterminal telopeptide of type I collagen (ICTP), β-CTX, and N-MID were also measured. The correlation analysis between N-MID and other indicators was conducted. The risk factors for osteoporosis were analyzed by logistic regression analysis, and receiver operating characteristics curve (ROC) were drawn to determine the diagnostic value of N-MID for osteoporosis. The measurement data were compared between the two groups by the independent-sample t test. Results　The thoracic BMD, lumbar BMD, hip BMD, leptin, 25(OH)D3, BAP, and N-MID in the osteoporotic group were lower than those in the non-osteoporotic group (all P<0.05). The PICP, ICTP, β-CTX, and HbA1c in the osteoporotic group were higher than those in the non-osteoporosis group (all P<0.05). N-MID was positively correlated with thoracic BMD, lumbar BMD, hip BMD, leptin, 25(OH)D3, and BAP (r=0.374, 0.501, 0.428, 0.672, 0.691, and 0.807; all P<0.05), and negatively with PICP, ICTP, β-CTX, and HbA1c (r=-0.419, -0.293, -0.313, and -0.405; all P<0.05). Binary logistic regression analysis showed that N-MID was an independent risk assessment factor for the osteoporosis patients (OR=2.85, P<0.05). The area under the ROC for the diagnosis of osteoporosis by serum N-MID was 0.851 (95%CI 0.724-0.943), so it had certain diagnostic value for osteoporosis (Z=4.073, P<0.001). Taking the N-MID concentration of 12.26 μg/ml as the diagnostic cut-off value, the sensitivity and specificity of N-MID in the diagnosis of osteoporosis were 83.93% and 72.61%, respectively. Conclusion　The serum N-MID level in elderly male patients with T2DM and osteoporosis decreases, and is an independent risk factor for osteoporosis, so it may serve as a diagnostic indicator for T2DM combined with osteoporosis in elderly men.

Key words: N-terminal osteocalcin, Old age, Male, Type 2 diabetes mellitus, Osteoporosis

摘要： 目的　探讨N-端骨钙素（N-MID）与老年男性2型糖尿病（T2DM）患者骨质疏松的相关性。方法　回顾性分析2015年1月至2019年12月在德州市人民医院门诊和住院治疗的100例≥60岁男性T2DM患者的临床资料，根据骨密度（BMD）水平将患者分为非骨质疏松组（62例）和骨质疏松组（38例）。对所有患者的BMD进行测量，同时检测血清中瘦素（Leptin）、25羟维生素D3［25（OH）D3］、特异性碱性磷酸酶（BAP）、Ⅰ型前胶原羧基末端前肽（PICP）、Ⅰ型胶原交联羧基末端肽（ICTP）、Ⅰ型胶原羟基端肽β降解产物（β-CTX）和N-MID水平；进行N-MID与其他指标的相关分析；分析骨质疏松的危险因素，绘制出研究对象受试者工作特征曲线（ROC），确定N-MID对骨质疏松的诊断价值。计量资料组间比较采用独立样本t检验。结果　骨质疏松组患者的胸椎BMD、腰椎BMD、髋BMD、Leptin、25（OH）D3、BAP和N-MID均低于非骨质疏松组患者（均P<0.05）；骨质疏松组患者的PICP、ICTP、β-CTX和糖化血红蛋白（HbA1c）均高于非骨质疏松组患者（均P<0.05）。N-MID与胸椎BMD、腰椎BMD、髋BMD、Leptin、25（OH）D3和BAP均呈正相关（r=0.374、0.501、0.428、0.672、0.691、0.807，均P<0.05）；N-MID与PICP、ICTP、β-CTX和HbA1c均呈负相关（r=-0.419、-0.293、-0.313、-0.405，均P<0.05）；二元logistic回归分析结果显示，N-MID是骨质疏松患者评估的独立危险因素（OR=2.85，P<0.05）；血清N-MID诊断骨质疏松的ROC下面积为0.851（95%CI 0.724～0.943），对骨质疏松具有一定的诊断价值（Z=4.073，P<0.001）。以N-MID浓度为12.26 μg/ml作为诊断截点，N-MID诊断骨质疏松的灵敏度和特异度依次为83.93%和72.61%。结论　老年男性T2DM合并骨质疏松患者血清中N-MID降低，是骨质疏松的独立危险因素，可能作为老年男性T2DM合并骨质疏松诊断指标。

关键词: N-端骨钙素, 老年, 男性, 2型糖尿病, 骨质疏松