title: Hemoglobin A1c above threshold level is associated with decreased β-cell function in overweight Latino youth.
abstract: OBJECTIVE
  To examine whether a hemoglobin A1c (HbA1c)-identified prediabetic state (HbA1c ≥ 6.0%-6.4%) is associated with decreased insulin sensitivity (SI) and β-cell dysfunction, known factors in the pathogenesis of type 2 diabetes, in an overweight pediatric population.
  
  
  METHODS
  A total of 206 healthy overweight Latino adolescents (124 males and 82 females; mean age, 13.1 ± 2.0 years) were divided into 2 groups: lower risk (n=179), with HbA1c <6.0%, and higher risk (n=27), with HbA1c 6.0%-6.4%. Measurements included HbA1c, oral glucose tolerance testing, fasting and 2-hour glucose and insulin, SI, acute insulin response, and disposition index (an index of β-cell function) by the frequently sampled intravenous glucose tolerance test with minimal modeling. Body fat was determined by dual-energy X-ray absorptiometry.
  
  
  RESULTS
  Compared with the lower risk group, the higher risk group had 21% lower SI (1.21 ± 0.06 vs 1.54 ± 0.13; P<.05), 30% lower acute insulin response (928 ± 102 vs 1342 ± 56; P<.01), and a 31% lower disposition index (1390 ± 146 vs 2023 ± 83; P=.001) after adjusting for age and total percent body fat.
  
  
  CONCLUSIONS
  These data provide clear evidence of greater impairment of β-cell function in overweight Latino children with HbA1c 6.0%-6.4%, and thereby support the adoption of the International Expert Committee's HbA1c-determined definition of high-risk state for overweight children at risk for type 2 diabetes.
authors.affiliation: Department of Preventive Medicine, University of Southern California, Los Angeles, CA, USA.
authors.forename: Claudia M
authors.initials: CM
authors.lastname: Toledo-Corral
authors.forename: Lisa G
authors.initials: LG
authors.lastname: Vargas
authors.forename: Michael I
authors.initials: MI
authors.lastname: Goran
authors.forename: Marc J
authors.initials: MJ
authors.lastname: Weigensberg
mesh_terms: D000293:Adolescent; D017677:Age Distribution; D015992:Body Mass Index; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis* / Q000208:ethnology; D005260:Female; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000032:analysis* / Q000378:metabolism; D006630:Hispanic or Latino / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D007333:Insulin Resistance / Q000502:physiology; D050417:Insulin-Secreting Cells / Q000378:metabolism*; D008297:Male; D050177:Overweight / Q000097:blood* / Q000208:ethnology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012016:Reference Values; D018570:Risk Assessment
chemical_list: D006442:Glycated Hemoglobin