Diabetes, Vol 44, Issue 7 796-801, Copyright © 1995 by American Diabetes Association
The Wisconsin Epidemiologic Study of Diabetic Retinopathy. XVI. The relationship of C-peptide to the incidence and progression of diabetic retinopathy
R Klein, BE Klein and SE Moss
Department of Ophthalmology and Visual Sciences, University of Wisconsin Medical School, Madison 53705-2397, USA.
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.