Correlation Between Serum Level Of GLP-1 And Mild Cogntive Impairment In Type 2 Diabetic Patients

Background:The prevalence of diabetes in the world is increasing year by year with the people’s living standards improve, an aging population, lifestyle changes, a serious threat to human health; Chronic complications of diabetes may be throughout the whole body organs, pathogenesis so complex as to not yet fully understood; It not only can cause diabetes macrovascular disease, microvascular disease, and other chronic diabetic complications, several epidemiological studies have found that diabetes and cognitive impairment was positively correlated with the incidence of type 2 central nervous system damage caused by diabetes, which can cause changes in brain structure and function, mainly for mild cognitive impairment (MCI). Glucagon-like peptide-1 (GLP-1) is a peptide hormone secreted by the intestinal L-cells after food stimulation with that can binding with GLP-1 receptor that is widely distributed in a variety of organs and organizations in the body. although the main physiological function is associated with blood glucose control and insulin resistance, the glp-1 can enhance blood glucose dependence on insulin secretion, reduce the blood sugar level in patients with type 2 diabetes, the glp-1 agonists have been approved for the treatment of diabetes, but there are more and more evidence proved that it may play an important role in cognitive function. Inadequate secretion of glp-1 is one of the characteristics of type 2 diabetes. But so far, study of relationship between the serum level of GLP-1 and the mild cognitive impairment in type 2 diabetic patients is less.Objective:The objective of the present study was to approach whether or not serum level of GLP-1 is an independent risk factor for MCI in patients with type 2 diabetes mellitus and find out risk factors and protective factors of MCI in patients with type 2 diabetes mellitus.Subjects and Methods:From July 1,2015 to September 30,2015,153 participants were recruited from outpatients of the Endocrine and Metabolic clinic and inpatients of the Endocrine Department in the Second Hospital of ShanDong University. The 153 participants were divided 3groups:normal control (NC) group, Type 2 diabetes patients without mild cognitive impairment (DM) group, type 2 diabetes patients with mild cognitive impairment (MCI-DM) group. All subjects should be collected general information, family history, history information and physical examination. After having fasted overnight, Fasting Blood Glucose (FBG), Total cholesterol (TC), Low-density cholesterol (LDL-C), High-density cholesterol (HDL-C), Triglycerides (TG), Uric Acid (UA) and serum level of GLP-1 were measured. Serum GLP-1level was quantified using an human GLP-1 enzyme-linked immunosorbent assays kit. The Montreal Cognitive Assessment (MoCA) was applied to assess the cognitive situation of each participant as a brief screening tool for MCI. For all analyses, we used Statistical Package for the Social Science (SPSS) 19.0 to examine between-subject differences. All continuous data were tested for normality with Kolmogorov-Smirnov (K-S) test or Shapiro-Wilk test. For non-normally distributed data log conversion. The one-way analysis of variance (ANOVA) was applied to compare the differences of the measurement data between the groups. Bivariate correlation analysis was used to analyze the correlation of groups and other indexes. Multinomial logistic regression analysis was used to see which factors, if any, predicted cognitive function. A p-value of less than 0.05 was considered to be statistically significant.Results:Subjects in the MCI-DM group, women are more likely to suffer cognitive dysfunction. MCI subjects had higher FBG, TC level and lower GLP-1, HDL-C level, years of education than other subjects (p<0.05). Bivariate correlation analysis indicated that MCI in T2DM were closely correlated with years of education, family history of diabetes, history of hypertension, as well as FBG, HDL-C, serum GLP-1 level. On multinomial logistic regression analysis, we testified that no history of hypertension (OR=0.106; 95%CI:0.018-0.647) and HDL-C (OR= 0.020; 95%CI: 0.001-0.599) were protect factors (P<0.005) possibly associated with MCI in patients with T2DM, while as well as years of education(<12years) (OR=12.795; 95%CI: 2.034-80.509) and FBG (OR= 2.625E9; 95%CI:8625.438-8.339E14) were found as risk factors (P<0.005). GLP-1 level (OR=0.142; 95%CI:0.005-3.934) cannot be proved an independent risk factors of MCI in patients with T2DM.Conclusion:The results show that no history of hypertension and HDL-C were protect factors possibly associated with MCI in patients with T2DM, while as well as years of education (<12years) and FBG level were found as risk factors. In MCI-DM group patients the serum GLP-1 level was obviously lower than the other groups subjects. But there was no strong evidence support that GLP-1 is an independent risk factor for MCI in diabetes.