不同血糖切点的空腹血糖调节受损的老年人群代谢特征及胰岛素抵抗比较

目的 探讨不同血糖切点的空腹血糖调节受损（IFG）的老年人群的代谢、胰岛素抵抗及胰岛β细胞功能等方面的差异。方法 空腹血糖（FPG）＜7.0mmol/L的830名非糖尿病健康查体者，根据FPG水平分为3组：正常糖代谢组510例：FPG＜5.6mmol/L ；新增人群（IFG1）组167例：5.6mmol/L ≤FPG＜6.1mmol/L；原人群(IFG2)组153例： 6.1mmol/L ≤FPG＜7.0mmol/L。测量血压、身高、体质量、腰围、臀围，计算体质量指数(BMI)、腰臀比(WHR)，同时酶法测定甘油三酯(TG)、总胆固醇(TC)、高密度脂蛋白(HDL-C)、低密度脂蛋白(LDL-C)、FPG及口服葡萄糖耐量试验(OGTT)2h血糖(2hPG)；放射免疫法测空腹胰岛素(FINS)及OGTT 2h胰岛素(PINS)，计算稳态模型胰岛素抵抗指数(HOMA-IR)及 B细胞功能指数(HOMA-B)。Logistic回归分析IFG1、IFG2发生餐后高血糖及代谢综合征(MS)的风险。结果 与正常糖代谢组相比，IFG两组患者年龄、血压、BMI、WHR、TC、TG 、LDL-C、FPG、2hPG和HOMA-IR均显著升高(P<0.05)，而HDL-C与HOMA B水平显著降低 (P<0.05)。IFG2组的2hPG明显高于IFG1组(P<0.05)。与IFG1组相比，IFG2组HOMA IR明显升高(P<0.05)；HOMA-B水平有下降趋势但差异无统计学意义(P>0.05)。Logistic回归分析显示，与IFG1组相比，IFG2组发生餐后高血糖及MS的风险明显升高。结论 老年IFG人群存在胰岛B细胞功能下降及胰岛素的抵抗，促进了糖尿病的发生发展；IFG2人群代谢紊乱与胰岛素抵抗更严重，与餐后高血糖及MS的关系更为密切。

Metabolic characteristics and insulin resistance in elderly patients with different thresholds for impaired fasting glucose

Objective    To investigate metabolic characteristics, insulin resistance (IR) and islet B-cell function in elderly subjects with different thresholds for impaired fasting glucose(IFG). Methods    A cohort of 830 nondiabetic subjects older than 60 years with fasting plasma glucose(FPG)＜7.0mmol/L were divided into three groups：the normal glucose tolerance(NGT) group(n=510) with FPG＜5.6mmol/L, the IFG1group(n=167) with 5.6mmol/L ≤FPG＜6.1mmol/L, and the IFG2 group(n=153) with 6.1 mmol/L ≤FPG＜7.0mmol/L.  Height, weight, blood pressure, waist circumference and hip circumference were measured, and the body mass index(BMI) and waist hip ratio(WHR) were calculated. Triglyceride(TG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol(LDL -C), FPG and 2h post-75g oral glucose tolerance test(OGTT) plasma glucose(2hPG) were determined. Fasting insulin(FINS) and 2h post-OGTT insulin(PINS)were measured by radioimmunoassay.The homeostasis model assessment (HOMA) was applied to assess the status of insulin resistance (HOMA-IR) and islet B-cell function (HOMA-B). Associations of IFG1 and IFG2 with risks of post-challenge glucose intolerance and metabolic syndrome (MS) were tested by logistic regression analysis with adjustment for age and gender. Results     Compared with the NGT group, age, WHR, BMI, blood pressure, TC, LDL-C, TG, FPG and 2hPG were elevated in the IFG1 and IFG2 groups(P<0.05). Subjects with IFG2 had  significantly higher 2hPG than those with IFG1(P<0.05). After adjustment for age, sex and BMI, HOMA-IR increased in subjects with IFG(P<0.05), and subjects with IFG2 had higher HOMA-IR(P<0.05). Compared with subjects with NGT, subjects with IFG had lower HOMA-B, while there was no significant difference between IFG1 and IFG2(P>0.05). In logistic regression analysis with adjustment for age and gender, IFG2 was associated with higher risks of post-challenge glucose intolerance and MS compared with IFG1. Conclusions    Insulin resistance and B cell dysfuction are present in elderly subjects with different thresholds for IFG. IFG2 is associated with more serious metabolic disorders and insulin resistance, and it is much more likely to have risks of post-challenge glucose intolerance and MS.