2型糖尿病性骨质疏松危险因素及定量CT的早期诊断

目的探讨2型糖尿病性骨质疏松的危险因素及定量CT在疾病早期诊断中的应用价值。 方法选取2016年2月至2017年2月期间在苏北人民医院治疗的2型糖尿病患者220例，研究对象同时接受双能X线吸收定量法（DXA）和定量CT两种方法分别检测腰椎骨密度和体积骨密度，根据DXA测量的椎体骨密度结果分为骨质疏松组和非骨质疏松组。比较2组性别、年龄、病程、BMI、空腹血糖（FPG）、餐后2 h血糖（2hPG）、空腹C肽（FCP）及餐后2 h C肽（2hCP）、糖化血红蛋白（HbA1c）、总胆固醇、三酰甘油、高密度脂蛋白胆固醇（HDL-C）、低密度脂蛋白胆固醇（LDL-C）、碱性磷酸酶、血磷、血钙、甲状旁腺激素（PTH）、Ⅰ型胶原羧基末端肽（CTx）、血清骨钙素（N-MID）、Ⅰ型胶原氨基末端肽（TP1NP）、维生素D、肌酐等指标的差异并行相关和回归分析。 结果2型糖尿病患者女性骨质疏松患病率较男性高（46.4% vs 29.3%；χ²=8.319，P=0.012）；骨质疏松组年龄、病程、HbA1c、PTH、CTx较非骨质疏松组高（P<0.05），骨质疏松组BMI、N-MID、TP1NP、维生素D较非骨质疏松组低（P<0.05）；CTx与2hPG呈负相关（r=-0.165，P<0.05）；TP1NP与FPG（r=-0.224）、2hPG（r=-0.191）呈负相关（P<0.05）；N-MID与FPG（r=-0.280）、2hPG（r=-0.183）、三酰甘油（r=-0.293）、HbA1c（r=-0.238）呈负相关（P<0.05）；维生素D与病程（r=-0.224）呈负相关，与BMI（r=0.167）呈正相关（P<0.05）。2型糖尿病患者腰椎骨密度与年龄（r=-0.371）、HbA1c（r=-0.173）、病程（r=-0.230）呈负相关（P<0.05），与BMI呈正相关（r=0.231，P<0.05）。2型糖尿病患者腰椎骨密度与年龄、病程、BMI、HbA1c、PTH、CTx有线性回归关系；定量CT与DXA检测方法相比，敏感度为100%，特异度为80.3%，定量CT诊出率较DXA高（P<0.05）。 结论（1）糖代谢和骨代谢有相关关系，血糖控制不佳，骨形成减少；（2）女性、高龄、病程长、血糖控制不佳是骨质疏松症的主要危险因素，BMI在一定范围适度增加为骨质疏松症的保护因素；（3）年龄、HbA1c、病程、PTH、CTx、BMI对腰椎骨密度的影响依次增大；（4）定量CT对2型糖尿病性骨质疏松的诊断具有更高的应用价值。

Type 2 diabetic osteoporosis: risk factors and early diagnosis by quantitative CT

ObjectiveTo identify the risk factors for osteoporosis (OP) associated with type 2 diabetes mellitus (T2DM), and to assess the clinical application values of quantitative CT in the early diagnosis of this condition. MethodsWe selected 220 T2DM patients at Northern Jiangsu People′s Hospital as study subjects. Dual-energy X-ray absorptiometry (DXA) and quantitative CT were used to detect the bone mineral density (BMD) and volume bone mineral density of the lumbar spine, respectively. The patients were divided into either an OP group or a non-OP group according to the BMD of the lumbar spine detected by DXA. Gender, age, duration of disease, BMI, FPG, 2hPG, FCP, 2hCP, HbA1c, CHO, TG, HDL-C, LDL-C, alkaline phosphatase, phosphorus, calcium, parathormone (PTH), CTx, N-MID, TP1NP, vitamin D, and creatinine were compared between the two groups, and correlation and regression analyses were also performed. ResultsThe prevalence of OP in women was higher than that in men (46.4% vs 29.3%, χ²=8.319, P=0.012). The average age, duration of disease, HbA1c, PTH, and CTx of the OP group were significantly higher than those of the non-OP group (P<0.05). BMI, N-MID, TP1NP, and vitamin D in the OP group were significantly lower than those in the non-OP group (P<0.05). CTx was negatively associated with 2hPG (r=-0.165, P<0.05). TP1NP was negatively associated with FPG (r=-0.224, P<0.05) and 2hPG (r=-0.191, P<0.05). N-MID was negatively associated with FPG (r=-0.280, P<0.05), 2hPG (r=-0.183, P<0.05), TG (r=-0.293, P<0.05), and HbA1c (r=-0.238, P<0.05). Vitamin D was inversely associated with duration of T2DM (r=-0.224, P<0.05) and positively associated with BMI (r=0.167, P<0.05). BMD of the lumbar spine in T2DM patients was negatively correlated with age (r=-0.371, P<0.05), HbA1c (r=-0.173, P<0.05), and duration of T2DM (r=-0.230, P<0.05), and positively correlated with BMI (r=0.231, P<0.05). There was a linear regression relationship between BMD of the lumbar spine and age, duration, BMI, HbA1c, PTH, and CTx in T2DM patients. Compared with DXA, quantitative CT had a sensitivity of 100% and specificity of 80.3% in the early diagnosis of type 2 diabetic osteoporosis. ConclusionPoor glucose control is associated with decreased bone formation in T2DM patients. Female gender, advanced age, long duration of T2DM, and poor blood glucose control are the main risk factors for OP, while BMI in a certain range is a protective factor for OP. The influence of age, HbA1c, duration of T2DM, PTH, CTx, and BMI on BMD of the lumbar vertebrae gradually increases. Compared with DXA, quantitative CT has greater value in the early diagnosis of type 2 diabetic osteoporosis.