2型糖尿病发病过程及病程与胰岛素释放功能变化的关系

The change of insulin secretion function in pre-diabetic stages and in different diagnostic duration of type 2 diabetes mellitus

目的 探讨 2型糖尿病不同的发生发展过程中胰岛素释放功能的变化。方法 在住院病人中收集具有不同诊断病程的 2型糖尿病患者 ,根据病程不同进行每隔一年的分组直到 1 0年以上组。在本单位年度跟踪体检人群中选择血糖正常 (空腹和 2 h均正常 )、可疑血糖异常、不同的糖调节受损、初诊糖尿病多组人群。对全部研究对象进行 5个时相点 75 g葡萄糖耐量试验和同步胰岛素释放试验 ,并测定糖化血红蛋白和甘油三酯等。结果 (1 )在筛查人群 ,与正常糖耐量相比较 ,糖尿病前期阶段的空腹、糖刺激最大胰岛素释放、胰岛素曲线下面积均明显著升高。(2 )在已诊断糖尿病人群 ,诊断病程 1～ 5年组空腹血糖继续代偿性增高 ,到病程第 6年组 ,空腹胰岛素下降一半 ;最大胰岛素水平从病程第 1年组开始下降到代偿最高水平的一半 ,并维持到病程第 5年组 ,从病程第 6年组又下降一半 (约 30 m IU/ L )。 (3)筛查人群在向糖尿病发生过程中胰岛素释放倍增幅度逐渐下降 ,其中单纯空腹血糖受损最明显 ;已诊断糖尿病人群胰岛素释放倍增幅度随病程增加逐渐减少。 (4)校正年龄、体重指数、甘油三酯、空腹血糖、葡萄糖曲线下面积 ,已诊断糖尿病人群病程与 OGTT0、30、60 min胰岛素水平 ,最大胰岛素水平 ,胰岛素释放倍增 (峰基比值 ) 。

Objective To explore the dynamic changes of insulin secretion during the progression of type 2 diabetes mellitus Methods Type 2 diabetic inpatients with different progress were recruited and grouped by one year duration added till to greater than 10 years And the individuals of the following groups: normal glucose (both fasting and 2 hour normal), suspicious dysglycaemia (SDG), various forms of impaired glucose regulation (IGR) and newly diagnosed type 2 diabetes, came from the screened people, for whose yearly health examination we are responsible All participators received 75 oral glucose tolerance test (OGTT) and synchronic serum insulin detections of five time points, and other relevant parameters were also measured Results 1) In screened people the fasting insulin, maximal insulin stimulated by glucose and area under the insulin curve in non normal groups all significantly elevated compared with normal glucose group 2) In known diabetic patients, fasting insulin levels of those with 1 to 5 years duration continued to compensate to a higher level, but dropped abruptly by half in 6 years duration group and remained the level till to >10 years groups; while the maximal insulin levels of the same groups decreased to be half of the previous compensated level from 1 year duration, and remained the level till to 5 years group, and in 6 years group there also were a sudden drop of half 3) In screened people during the progression to diabetes the increased fold of insulin induced by glucose decreased gradually, and isolated impaired fasting glucose was the poorest In known diabetic patients the increased fold of insulin decreased slowly with the duration increasing 4) After adjustment for age, body mass index, triglyceride level, fasting glucose and area under the glucose curve and the diabetes duration were negatively correlated with the insulin levels of 0, 30, 60 min during OGTT, maximal insulin, the increased fold of insulin and area under the insulin curve significantly 5) In screened people, a multivariate regression showed that the glucose of 0, 30, 180 min was correlated with insulin positively, but body mass index was only related with fasting insulin positively Further analysis demonstrated that the positive correlation of body mass index with insulin levels presented in normal glucose and SDG groups but not in impaired glucose regulation and newly diabetes groups Conclusions This cross sectional study showed that various pre diabetic types of glucose metabolism presented substantially compensatory increase of insulin secretion But for known diabetic patients, in the general tendency of gradually drop of insulin secretion there were abrupt changes at the 1 year and 6 year duration and these patients' increased folds of maximal insulin from basal value decreased continuously