title: Estimating insulin secretion in youth using simple indices derived from the oral glucose tolerance test.
abstract: OBJECTIVE
  Simple estimates of insulin secretion feasible for large epidemiological studies have been proposed in adults, but have been little evaluated in young people. For this reason, this study examined the correlation between OGTT-derived and fasting-based indices of insulin secretion against the acute insulin response to glucose (AIRg) in children.
  
  
  METHODS
  Twenty subjects (nine boys and 11 girls; mean [SD] age: 9 [2] years) were studied. Their mean (SD) BMI Z score was 1.5 (0.8). All participants had normal fasting and 2-h post-load glucose. Each subject underwent an insulin-modified minimal model frequently sampled intravenous glucose tolerance test (FSIVGTT) as the reference method, and a 3-h OGTT. AIRg was computed from the FSIVGTT. A total of ten indices were calculated using OGTT data, while HOMA%beta (original formula) and HOMA2%beta (computer-based) were computed from fasting samples. Correlations were established using Spearman's rank correlations.
  
  
  RESULTS
  Of the ten indices derived from the OGTT, those most closely correlated with the AIRg (using FSIVGTT) included the insulinogenic index(t30)(min) (r = 0.80), insulin/glucose ratio(t30)(min) (r = 0.71) and ratio of the area under the curve for insulin to glucose(t0-30)(min) (r = 0.74). Both the HOMA%beta and HOMA2%beta correlated modestly with AIRg (r = 0.62 and r=0.65, respectively).
  
  
  CONCLUSIONS
  Our results suggest that OGTT-derived measures of insulin secretion provide adequate estimates of first-phase insulin secretion in youth. HOMA2%beta and HOMA%beta represent acceptable compromises, although HOMA2%beta may be preferable in younger individuals, as it allows for a wider spectrum of insulin and glucose values that are physiological in this age group.
authors.affiliation: Department of Epidemiology, Biostatistics and Occupational Health, McGill University, 1020, Pine Avenue West, Room 27, Montréal, Quebec, H3A 1A2, Canada. melanie.henderson@mail.mcgill.ca
authors.forename: M
authors.initials: M
authors.lastname: Henderson
authors.forename: J P
authors.initials: JP
authors.lastname: Baillargeon
authors.forename: R
authors.initials: R
authors.lastname: Rabasa-Lhoret
authors.forename: J L
authors.initials: JL
authors.lastname: Chiasson
authors.forename: J
authors.initials: J
authors.lastname: Hanley
authors.forename: M
authors.initials: M
authors.lastname: Lambert
mesh_terms: D000293:Adolescent; D001786:Blood Glucose / Q000378:metabolism*; D015992:Body Mass Index; D002648:Child; D005215:Fasting / Q000378:metabolism; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance / Q000502:physiology*; D000078790:Insulin Secretion; D008297:Male; D012016:Reference Values; D015203:Reproducibility of Results
chemical_list: D001786:Blood Glucose; D007328:Insulin