Changes in Features of the Metabolic Syndrome and Incident Impaired Glucose Regulation or Type 2 Diabetes in a Chinese Population

Abstract

The current understanding of the pathogenesis of type 2 diabetes is mainly based on a large number of cross-sectional and prospective studies (1– 4) in which nondiabetic individuals were followed for several years to determine incident cases of diabetes without repeating assessment of other metabolic characteristics except for assay of plasma glucose during follow-up. In fact, only the studies in the Pima Indian population (5–7) have examined the changes in anthropometric characteristics, insulin secretion, and insulin action during the progression from normal glucose tolerance (NGT) to impaired glucose tolerance (IGT) to diabetes. Thus far, no study has directly addressed the effects of changes in the components of the metabolic syndrome on the transition to diabetes in other populations. The purpose of this study was to investigate the changes in the features of the metabolic syndrome during the transition from one state of glucose homeostasis to another in a cohort of Chinese people and to understand the relative contributions of these changes to the development of impaired glucose regulation (IGR) or type 2 diabetes. RESEARCH DESIGN AND METHODS — A total of 627 subjects without diabetes at baseline who participated in the National Diabetes Survey in 1994 and the follow-up survey in 1999 in the Beijing area (8) were included in this study. All of the subjects had measurements of BMI, blood pressure, fasting serum total cholesterol, triglecerides, insulin, plasma fasting glucose, and 2-h postload glucose (2-hPG) at baseline and follow-up separately. Past medical history, family history of diabetes, history of pharmacological treatment, smoking status, education, and occupation were determined with a standardized questionnaire. Obesity was defined as BMI 25.0 kg/m 2 , according to the recommendations for Asians (9). Hy