title: Identifying hyperinsulinaemia in the absence of impaired glucose tolerance: An examination of the Kraft database.
abstract: OBJECTIVE
  Hyperinsulinaemia is associated with development of chronic metabolic disease and is emerging as a health risk independent to that of insulin resistance. However, little is known to what extent hyperinsulinaemia occurs with normal glucose tolerance in lean subjects.
  
  
  METHODS
  Oral glucose tolerance tests with concurrent insulin assay were conducted during the 1970s-1990s. Participants were classified according to glucose tolerance and insulin response pattern. Analysis of variance compared differences in plasma glucose, plasma insulin, and demographic and metabolic risk factors between groups.
  
  
  RESULTS
  Participants with normal glucose tolerance comprised 54% (n=4185) of the total cohort. Of these, just over half (n=2079) showed hyperinsulinaemia despite normal glucose clearance. Obesity had a modest association with hyperinsulinaemia in people with normal glucose tolerance. Fasting insulin had limited value in diagnosing hyperinsulinaemia. The majority of participants (93%) with impaired glucose tolerance or diabetes had concurrent hyperinsulinaemia.
  
  
  CONCLUSIONS
  Hyperinsulinaemia in the absence of impaired glucose tolerance may provide the earliest detection for metabolic disease risk and likely occurs in a substantial proportion of an otherwise healthy population. Dynamic insulin patterning may produce more meaningful and potentially helpful diagnoses. Further research is needed to investigate clinically useful hyperinsulinaemia screening tools.
authors.affiliation: Human Potential Centre, AUT University, Auckland, New Zealand. Electronic address: ccrofts@aut.ac.nz.
authors.forename: Catherine
authors.initials: C
authors.lastname: Crofts
authors.affiliation: Human Potential Centre, AUT University, Auckland, New Zealand.
authors.forename: Grant
authors.initials: G
authors.lastname: Schofield
authors.affiliation: Human Potential Centre, AUT University, Auckland, New Zealand.
authors.forename: Caryn
authors.initials: C
authors.lastname: Zinn
authors.affiliation: Department of Biostatistics and Epidemiology, AUT University, Auckland, New Zealand.
authors.forename: Mark
authors.initials: M
authors.lastname: Wheldon
authors.affiliation: Department of Clinical Pathology and Nuclear Medicine, St Joseph Hospital, Chicago, IL, USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Kraft
mesh_terms: D001786:Blood Glucose / Q000378:metabolism*; D016208:Databases, Factual; D005215:Fasting / Q000097:blood; D005260:Female; D018149:Glucose Intolerance / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology; D005951:Glucose Tolerance Test; D006801:Humans; D006946:Hyperinsulinism / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology; D007087:Illinois / Q000453:epidemiology; D015994:Incidence; D007328:Insulin / Q000097:blood*; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D012307:Risk Factors
chemical_list: D001786:Blood Glucose; D007328:Insulin
keywords: Diabetes; Hyperinsulinaemia; Insulin; Oral glucose tolerance test