title: Plasma glucose and insulin responses to mixed meals: impaired fasting glucose re-visited.
abstract: BACKGROUND
  In individuals with varying glucose tolerance, glucose and insulin comparisons are usually made based on response to oral glucose challenge. However, an oral glucose tolerance test may not reflect daylong glucose and insulin excursions in response to meals. To better understand individuals with impaired fasting glucose (IFG), we compared insulin action as well as plasma glucose and insulin responses to mixed meals in individuals with normal fasting glucose (NFG; n = 141) and IFG (n = 148) concentrations.
  
  
  METHODS
  Insulin action was quantified by determining steady-state plasma glucose (SSPG) concentrations during the insulin suppression test. Plasma glucose and insulin concentrations were measured before and hourly after two mixed meals.
  
  
  RESULTS
  SSPG concentrations were significantly higher in the IFG group (11.8 ± 3.6 vs. 9.1 ± 3.8 mmol/l). Mean hourly daylong glucose (6.4 ± 0.07 vs. 5.5 ± 0.04 mmol/l) and insulin (390 ± 20 vs. 279 ± 15 pmol/l) concentrations were also higher in those with IFG (p < 0.001). Daylong incremental meal-stimulated glucose response, however, was comparable (p = 0.77) in the two groups, whereas the incremental insulin response was 44% higher in the IFG group.
  
  
  CONCLUSIONS
  Although individuals are currently defined as having IFG based on fasting plasma glucose concentration, our data show that these individuals with IFG also are insulin resistant and have higher daylong insulin concentrations.
authors.affiliation: Stanford University School of Medicine, CA 94305-5103, USA.
authors.forename: Sl
authors.initials: S
authors.lastname: Bhat
authors.forename: F
authors.initials: F
authors.lastname: Abbasi
authors.forename: C
authors.initials: C
authors.lastname: Blasey
authors.forename: Gm
authors.initials: G
authors.lastname: Reaven
authors.forename: Sh
authors.initials: Sh
authors.lastname: Kim
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism*; D002140:California; D016022:Case-Control Studies; D005215:Fasting / Q000097:blood*; D005260:Female; D018149:Glucose Intolerance / Q000097:blood* / Q000175:diagnosis / Q000503:physiopathology; D006801:Humans; D007328:Insulin / Q000097:blood*; D007333:Insulin Resistance; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D019518:Postprandial Period; D013997:Time Factors
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D007328:Insulin