The Wisconsin Epidemiologic Study of Diabetic Retinopathy. XVI. The relationship of C-peptide to the incidence and progression of diabetic retinopathy

Diabetes. 1995 Jul;44(7):796-801. doi: 10.2337/diab.44.7.796.


The relationship between plasma C-peptide and the 6-year incidence and progression of diabetic retinopathy was examined in a population-based study in Wisconsin. Individuals with younger-onset (n = 548) and older-onset (n = 459) diabetes were included. C-peptide was measured by radioimmunoassay with Heding's M1230 antiserum. Retinopathy was determined from stereoscopic fundus photographs. Younger- and older-onset insulin-using individuals with undetectable or low plasma C-peptide (< 0.3 nmol/l) at baseline had the highest incidence and rates of progression of retinopathy, whereas older-onset individuals with C-peptides > 0.3 nmol/l had the lowest incidence and rates of progression of retinopathy. However, within each group (younger-onset using insulin, older-onset using insulin, and older-onset not using insulin), after we controlled for other characteristics associated with retinopathy, there was no relationship between higher levels of C-peptide at baseline and lower 6-year incidence or progression of retinopathy. These data suggest that glycemic control, and not C-peptide, is related to the incidence and progression of diabetic retinopathy.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Age of Onset
  • Biomarkers / blood
  • Blood Pressure
  • Body Mass Index
  • C-Peptide / blood*
  • Diabetes Mellitus / epidemiology
  • Diabetes Mellitus, Type 1 / blood
  • Diabetes Mellitus, Type 1 / physiopathology*
  • Diabetes Mellitus, Type 2 / blood
  • Diabetes Mellitus, Type 2 / physiopathology*
  • Diabetic Retinopathy / blood
  • Diabetic Retinopathy / epidemiology*
  • Diabetic Retinopathy / physiopathology*
  • Disease Progression
  • Female
  • Glycated Hemoglobin A / analysis
  • Humans
  • Incidence
  • Insulin / blood
  • Male
  • Obesity
  • Proteinuria
  • Wisconsin / epidemiology


  • Biomarkers
  • C-Peptide
  • Glycated Hemoglobin A
  • Insulin