title: Low association between fasting and OGTT stimulated glucose levels with HbA1c in overweight children and adolescents.
abstract: BACKGROUND
  Diabetes and prediabetes are defined based on different methods such as fasting glucose, glucose at 2-hour in oral glucose tolerance test (OGTT), and glycated hemoglobin A1c (HbA1c). These parameters probably describe different deteriorations in glucose metabolism limiting the exchange between each other in definitions of diabetes.
  
  
  OBJECTIVE
  To investigate the relationship between OGTT and HbA1c in overweight and obese children and adolescents living in Germany.
  
  
  METHODS
  Study population: Overweight and obese children and adolescents (n = 4848; 2668 female) aged 7 to 17 years without known diabetes. The study population was stratified into the following subgroups: normal glucose tolerance, prediabetes, diabetes according to OGTT and/or HbA1c categories, confirmed diagnosis of diabetes.
  
  
  RESULTS
  In the entire study group fasting plasma glucose (FPG) correlated weakly to 2-hour glucose (r = 0.26), FPG correlated weakly to HbA1c (r = 0.18), and 2-hour glucose correlated weakly to HbA1c (r = 0.17, all P < .001). Patients with confirmed diabetes showed a very high correlation between FPG and 2-hour glucose (r = 0.73, n = 50). Moderate correlations could be found for patients with impaired fasting glucose (2-hour glucose vs HbA1c: r = 0.30, n = 436), for patients with diabetes according to OGTT and/or HbA1c (FPG vs 2-hour glucose: r = 0.43; 2-hour glucose vs HbA1c: r = -0.30, n = 115) and for patients with confirmed diabetes (2-hour glucose vs HbA1c: r = -0.47, all P < .001).
  
  
  CONCLUSIONS
  Because FPG, 2-hour glucose, and HbA1c correlated only weakly we propose that these parameters, particularly in the normal range, might reflect distinct aspects of carbohydrate metabolism.
authors.affiliation: Public Health Department of Stuttgart, Department of Pediatrics, Dental Health Care, Health Promotion and Social Services, Stuttgart, Germany.|Pediatric Endocrinology and Diabetes, University Children's Hospital, University of Tübingen, Tübingen, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Ehehalt
authors.affiliation: Department of Pediatric Endocrinology and Diabetes, Charité Children's Hospital, Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Susanna
authors.initials: S
authors.lastname: Wiegand
authors.affiliation: Hospital for Children and Adolescents, Department of Women and Child Health, University Hospitals, University of Leipzig, Leipzig, Germany.
authors.forename: Antje
authors.initials: A
authors.lastname: Körner
authors.affiliation: Pediatric Endocrinology and Diabetes, University Children's Hospital, University of Tübingen, Tübingen, Germany.
authors.forename: Roland
authors.initials: R
authors.lastname: Schweizer
authors.affiliation: Endokrinologikum Berlin am Gendarmenmarkt, Berlin, Germany.
authors.forename: Klaus-Peter
authors.initials: KP
authors.lastname: Liesenkötter
authors.affiliation: Endokrinologikum Hamburg, Hamburg, Germany.
authors.forename: Carl-Joachim
authors.initials: CJ
authors.lastname: Partsch
authors.affiliation: Department of Clinical Epidemiology and Applied Biometry, University of Tübingen, Tuebingen, Germany.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Blumenstock
authors.affiliation: Hospital for Children and Adolescents, Department of Women and Child Health, University Hospitals, University of Leipzig, Leipzig, Germany.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Spielau
authors.affiliation: Division of Pediatric Endocrinology and Diabetes, Interdisciplinary Obesity Unit, Department of Pediatrics and Adolescent Medicine, Ulm University, Ulm, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Denzer
authors.affiliation: Pediatric Endocrinology and Diabetes, University Children's Hospital, University of Tübingen, Tübingen, Germany.
authors.forename: Michael B
authors.initials: MB
authors.lastname: Ranke
authors.affiliation: Pediatric Endocrinology and Diabetes, University Children's Hospital, University of Tübingen, Tübingen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Neu
authors.affiliation: Pediatric Endocrinology and Diabetes, University Children's Hospital, University of Tübingen, Tübingen, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Binder
authors.affiliation: Division of Pediatric Endocrinology and Diabetes, Interdisciplinary Obesity Unit, Department of Pediatrics and Adolescent Medicine, Ulm University, Ulm, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Wabitsch
authors.affiliation: Hospital for Children and Adolescents, Department of Women and Child Health, University Hospitals, University of Leipzig, Leipzig, Germany.
authors.forename: Wieland
authors.initials: W
authors.lastname: Kiess
authors.affiliation: Department of Pediatric Endocrinology, Diabetes and Nutrition Medicine, Vestische Children's Hospital, University Witten/Herdecke, Datteln, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Reinehr
mesh_terms: D000293:Adolescent; D001786:Blood Glucose; D050260:Carbohydrate Metabolism; D002648:Child; D003430:Cross-Sectional Studies; D005215:Fasting / Q000097:blood*; D005260:Female; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D016014:Linear Models; D008297:Male; D050177:Overweight / Q000097:blood*
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human
keywords: 
  HbA1c
  ; 
  OGTT
  ; children; diabetes; overweight