title: Both fasting and glucose-stimulated proinsulin levels predict hyperglycemia and incident type 2 diabetes: a population-based study of 9,396 Finnish men.
abstract: BACKGROUND
  Hyperproinsulinemia is an indicator of β-cell dysfunction, and fasting proinsulin levels are elevated in patients with hyperglycemia. It is not known whether proinsulin levels after a glucose load are better predictors of hyperglycemia and type 2 diabetes than fasting proinsulin.
  
  
  METHODS
  Participants were 9,396 Finnish men (mean±SD, age 57.3±7.1 years, BMI 27.0±4.0 kg/m2) of the population-based METabolic Syndrome In Men Study who were non-diabetic at the recruitment, and who participated in a 6-year follow-up study. Proinsulin and insulin levels were measured in the fasting state and 30 and 120 min after an oral glucose load. Area under the curve (AUC) and proinsulin to insulin ratios were calculated.
  
  
  RESULTS
  Fasting proinsulin, proinsulin at 30 min and proinsulin AUC during the first 30 min of an oral glucose tolerance test significantly predicted both the worsening of hyperglycemia and type 2 diabetes after adjustment for confounding factors. Further adjustment for insulin sensitivity (Matsuda index) or insulin secretion (Disposition index) weakened these associations. Insulin sensitivity had a major impact on these associations.
  
  
  CONCLUSIONS
  Our results suggest that proinsulin in the fasting state and after an oral glucose load similarly predict the worsening of hyperglycemia and conversion to type 2 diabetes.
authors: Faculty of Health Sciences, Institute of Clinical Medicine, Internal Medicine, University of Eastern Finland, Kuopio, Finland.
authors: Jagadish
authors: J
authors: Vangipurapu
authors: Faculty of Health Sciences, Institute of Clinical Medicine, Internal Medicine, University of Eastern Finland, Kuopio, Finland.
authors: Alena
authors: A
authors: Stančáková
authors: Faculty of Health Sciences, Institute of Clinical Medicine, Internal Medicine, University of Eastern Finland, Kuopio, Finland.
authors: Teemu
authors: T
authors: Kuulasmaa
authors: Faculty of Health Sciences, Institute of Clinical Medicine, Internal Medicine, University of Eastern Finland, Kuopio, Finland; Department of Medicine, Kuopio University Hospital, Kuopio, Finland.
authors: Johanna
authors: J
authors: Kuusisto
authors: Faculty of Health Sciences, Institute of Clinical Medicine, Internal Medicine, University of Eastern Finland, Kuopio, Finland; Department of Medicine, Kuopio University Hospital, Kuopio, Finland.
authors: Markku
authors: M
authors: Laakso
mesh_terms: D000368:Aged; D019540:Area Under Curve; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism*; D003920:Diabetes Mellitus / Q000097:blood / Q000175:diagnosis*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000175:diagnosis*; D005215:Fasting; D005387:Finland; D005500:Follow-Up Studies; D005951:Glucose Tolerance Test; D006801:Humans; D006943:Hyperglycemia / Q000097:blood / Q000175:diagnosis*; D007328:Insulin / Q000097:blood*; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011384:Proinsulin / Q000097:blood*
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D007328:Insulin; D011384:Proinsulin