title: Factors responsible for development from normal glucose tolerance to isolated postchallenge hyperglycemia.
abstract: OBJECTIVE
  Isolated postchallenge hyperglycemia (IPH), defined as fasting plasma glucose (FPG) level <7.0 mmol/l and 2-h plasma glucose (PG) level >/=11.1 mmol/l, is a subtype of early-stage diabetes. This study evaluates the metabolic profiles of insulin secretion and insulin sensitivity in IPH to clarify the factors responsible for development of this form of type 2 diabetes.
  
  
  METHODS
  We conducted cross-sectional analysis of 231 Japanese men aged 20-70 years. The subjects were classified into the following three groups, based on the results of a 75-g oral glucose tolerance test (OGTT): 1) normal glucose tolerance (NGT), defined as FPG level <6.1 mmol/l and 2-h PG level <7.8 mmol/l (n = 89); 2) impaired glucose tolerance (IGT), defined as FPG level <7.0 mmol/l and 2-h PG level of 7.8-11.1 mmol/l (n = 94); and 3) IPH (n = 48). We compared the three groups for insulin secretion (insulinogenic index) and insulin sensitivity (index of insulin resistance using homeostasis model assessment [HOMA-IR]).
  
  
  RESULTS
  The insulinogenic index in IPH was the lowest of the three groups (P < 0.001 versus NGT). The HOMA-IR in the IGT and IPH groups were significantly higher than in the NGT group (P < 0.001), but both were similar. By linear regression analysis, the insulinogenic index rather than fasting insulin or HOMA-IR was the more significant factor in the 2-h PG level in IGT and IPH.
  
  
  CONCLUSIONS
  Subjects with IPH exhibited distinctly impaired early-phase insulin secretion and only mild insulin resistance, indicating that reduced insulin secretion is the primary determinant of deterioration from NGT to IGT and IPH in development of type 2 diabetes in these subjects.
authors.affiliation: Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Suzuki
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Fukushima
authors.forename: Masaru
authors.initials: M
authors.lastname: Usami
authors.forename: Masaki
authors.initials: M
authors.lastname: Ikeda
authors.forename: Ataru
authors.initials: A
authors.lastname: Taniguchi
authors.forename: Yosikatsu
authors.initials: Y
authors.lastname: Nakai
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Matsuura
authors.forename: Akira
authors.initials: A
authors.lastname: Kuroe
authors.forename: Koichiro
authors.initials: K
authors.lastname: Yasuda
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kurose
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Seino
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Yamada
mesh_terms: D000328:Adult; D000368:Aged; D044466:Asian People; D001786:Blood Glucose / Q000378:metabolism*; D003430:Cross-Sectional Studies; D003920:Diabetes Mellitus / Q000235:genetics; D005190:Family; D005215:Fasting; D005951:Glucose Tolerance Test / Q000379:methods*; D006442:Glycated Hemoglobin / Q000032:analysis; D006029:Glycosuria; D006801:Humans; D006943:Hyperglycemia / Q000097:blood*; D007328:Insulin / Q000097:blood; D007564:Japan; D008297:Male; D008875:Middle Aged; D019518:Postprandial Period; D012016:Reference Values; D012044:Regression Analysis
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; D007328:Insulin