Study On Obesity And Islet Autoimmunity Of Middle - Aged And Elderly People

Part ⅠApplication of Adult Visceral Adiposity Index to Assess the Effects of Obesity on Arterial StiffnessObjective:The objective was to describe the relationship between obesity and brachial-ankle pulse wave velocity (baPWV) in order to investigate the heterogeneity of obesity and the effects of obesity on arterial stiffness. Methods:We collected the data of 5158 individuals over 40 years of age from a cross-sectional study of Nanjing, China. Anthropometric, demographic, hemodynamic measurements and arterial stiffness measured through brachial-ankle pulse wave velocity (baPWV) were obtained. Subjects were grouped through body mass index (BMI), waist circumference (WC) and visceral adiposity index (VAI). Each group was further grouped according to metabolic status. Results:The multivariate regression analysis revealed a negative but weak effect of the BMI (β=-0.047, P<0.001) on baPWV and failed to demonstrate any significant effect of WC on baPWV. While VAI was a positive independent indicator of baPWV (β=0.023, P=0.022). The unadjusted baPWV significantly increased across groups with higher obesity categories (P<0.01), the positive association was lost after adjustments for confounding factors in BMI or WC category (P>0.05) but still obtained between baPWV and VAI quartile (P<0.01). No differences were observed among the metabolically healthy groups or the metabolically abnormal groups in the BMI and WC category (P>0.05). However, baPWV significantly increased across groups with higher VAI categories even in the same metabolic category (P<0.01).Those with higher VAI category were lower insulin sensitivity (Fig 3a; P<0.001) and more insulin resistant (Fig 3b; P<0.001).Conclusion:This study supports the concept of heterogeneity of metabolic status among individuals within the same obesity range. Obese individuals are at increased risk of arterial stiffness regardless of their metabolic conditions. VAI is applicable for the assessment of the effect of obesity on arterial stiffness.Part ⅡDetection and Analysis of Islet Autoimm unity in Middle-Aged and Elderly Patients with Newly Diagnosed DiabetesObjective:The objective of this study was to detect and analyze the positive rate of islet autoantibodies in middle-aged and elderly patients with newly diagnosed diabetes, and to explore their clinical heterogeneity. Methods:Glutamic acid decarboxyase antibody (GADA), protein-tyrosine-phosphatase-2 autoantibody (IA-2A) and zinc transporter 8 antibody (ZnT8A) were detected in 889 middle-aged and elderly patients with newly diagnosed diabetes,787 type 1 diabetic patients and 115 healthy controls by radio-immuno-precipitation assay. The information of anthropometry parameters, biochemical factors, glucose and insulin concentrations were collected. Results:In the newly diagnosed diabetic patients, the positive rates of GADA, ZnT8A and IA-2A were 2.6%,3.9% and 4.0%. Patients with at least one positive antibody were 10.1%, and with at least two positive antibodies were 0.3%. The positive rates and antibody index of three islet antibodies were significantly lower than type 1 diabetic patients (P< 0.001). IA-2A had a higher positive rate (P=0.043) and antibody index (P=0.041) than healthy controls, while there were no significant differences in GADA or ZnT8 A. There were no significant differences in the positive rates between male and female (P>0.05). The positive rate of GADA in newly diagnosed diabetic patients less than 50 years of age was significantly higher than that of 50-59 years and older than 70 years (6.0% vs 1.1%, P=0.022; 6.0% vs 1.1%, P=0.031). The positive rate of ZnT8A decreased across groups with higher MatsudalSI quartiles (P=0.049), and increased across groups with higher HOMA-β (P=0.001). There were no statistical significance in the other indicators or the positive rate of other antibodies (P>0.05). Conclusions:The islet autoimmune responses in the middle-aged and elderly patients with newly diagnosed diabetes are not uncommon. The main characteristic of the autoimmune responses is that most of the patients have a single positive antibody. The autoimmune heterogeneity in the middle-aged and elderly diabetic patients needs further follow-up observation.