The relationships between hemoglobin and insulin resistance, glucose effectiveness, and first- and second-phase insulin secretion in adult Chinese

ABSTRACT Objective We denote the four major factors related to the development of type 2 diabetes (T2D) as "diabetes factor" (DF); increased insulin resistance (IR); decreased glucose effectiveness (GE); and the first-and-second-phase of insulin secretion (FPIS, SPIS). The level of hemoglobin (Hb) was found to be related to IR and FPIS, but no-known studies focused on its role in relation to SPIS and GE. In this study, we aim to evaluate the relationships between Hb and all four DFs in the same individual. Subjects and methods We randomly enrolled 24,407 men and 24,889 women between 30 and 59 years old. IR, FPIS, SPIS and GE were measured according to equations published in our previous studies. To compare the slopes between Hb and the four DFs with different units, we converted their units to percent of change per unit of increased Hb. Results Age, HDL-cholesterol and GE were higher in women; BMI, blood pressure, LDL-cholesterol, TG, Hb, FPIS, SPIS and IR were higher in men. After they were converted into percentage, the closeness of their relationships to Hb, from the highest to the lowest, were GE, IR, FPIS and SPIS for women and IR, GE, FPIS and SPIS for men. GE was the only one negatively related to Hb. Conclusions Our data showed that IR, FPIS and SPIS were both positively and, GE negatively, related to the Hb in adult Chinese. For women, GE had the closest association with Hb; for men, it was IR. Both phases of insulin secretion had relatively weaker relationships than IR and GE.

Factor analysis of metabolic syndrome using direct measurement of insulin resistance in Chinese with different degrees of glucose tolerance.

BACKGROUND & OBJECTIVE: With the increasing prevalence of type 2 diabetes and cardiovascular disease in Taiwan, the understanding of metabolic syndrome (MetS) becomes more important. The purpose of this study was to investigate the clustering patterns of the risk variables of the MetS with factor analysis (FacAn). METHODS: A total of 564 Chinese individuals with normal glucose tolerance (N, n=345), impaired glucose tolerance (IGT, n=164) or diabetes mellitus (DM, n=55) were enrolled. Insulin resistance was measured by insulin suppression test (IST). The components of MetS such as waist hip ratio (WHR), fasting plasma glucose (FPG), systolic blood pressure (SBP), diastolic blood pressure (DBP), triglyceride (TG), high density lipoprotein cholesterol (HDLC) and steady state plasma glucose (SSPG) from IST were put into the model of exploratory FacAn. RESULTS: In spite of the minor different loading patterns, three dimensions were identified in the three subgroups; a "blood pressure" dimension, loading with mainly SBP and DBP, an "insulin resistance" dimension, loading mainly with SSPG, and an "adiposity/glucose" dimension loading with TG, WHR or FPG. INTERPRETATION & CONCLUSION: Our results were consistent with different ethnic groups in earlier reports that more than two dimensions were identified and that the MetS is not unified by a single underlying aetiology, i.e., insulin resistance. Longitudinal analysis in this and other populations will be required to validate our findings and to test their generalisability.

Insulin resistance & secretion in subjects with normal fasting plasma glucose.

BACKGROUND & OBJECTIVES: Lowering the diagnostic threshold of normal fasting plasma glucose (FPG) from 6.1 to 5.56 mmol/l has been proposed by American Diabetes Association. As early detection of subjects with risk of diabetes is important, it is crucial to understand the relationship between different levels of FPG, insulin resistance (IR) and insulin secretion. We measured IR and insulin secretion in subjects with different levels of FPG to investigate the relationship between FPG and IR and insulin secretion, and to see whether lowering the cut-off improves the sensitivity of impaired fasting glucose to predict diabetes. METHODS: Apparently healthy subjects (294) were enrolled and divided into 3 groups according to their FPG levels; group 1 (<5.56 mmol/l, n=129), group 2 (5.56-6.09 mmol/l, n=99) and group 3 (6.1-6.9 mmol/l, n=66). Steady state plasma glucose (SSPG) derived from insulin suppression test was used to quantify insulin resistance and 30 min insulinogenic index during an oral glucose tolerance test to measure acute insulin secretion. RESULTS: The blood pressure was higher in group 3 than group 2 and fasting plasma insulin and triglyceride were higher in group 3 than that in group 1. The insulinogenic index was higher in the group 1 than group 3 and the SSPG was significantly higher in group 3 compared to group 1. INTERPRETATION & CONCLUSION: Our study showed a trend of progressive deterioration of both insulin action and secretion with increasing FPG level. These are supportive evidences for lowering the FPG to 5.56 mmol/l as suggested by the ADA.