Diabetes Care, Vol 20, Issue 8 1252-1255, Copyright © 1997 by American Diabetes Association
Proinsulin, intact insulin, and fibrinolytic variables and fibrinogen in healthy subjects. A population study
M Eliasson, ME Roder, B Dinesen, PE Evrin and B Lindahl
Department of Medicine, Lulea Hospital, Sweden. mats.eliasson@nll.se
OBJECTIVE: As high serum insulin predicts impaired fibrinolysis and
proinsulin reacts in most conventional insulin assays, we hypothesized that
proinsulin could link low fibrinolytic activity and hyperinsulinemic
conditions. RESEARCH DESIGN AND METHODS: We explored the relationship
between fibrinolysis and plasma fibrinogen on the one hand and specific
insulin and proinsulin on the other, in a healthy population sample of 165
men and women, 25-74 years of age, from the Northern Sweden MONICA
(Monitoring of Trends and Determinants in Cardiovascular Disease) Study.
Specific insulin and proinsulin were measured by enzyme-linked
immunosorbent assay. Partial correlation coefficients, adjusted for age and
sex, were calculated. RESULTS: Plasma fibrinogen levels were related to
insulin (r = 0.25, P < 0.01) and proinsulin (r = 0.29, P < 0.001), as
was plasminogen activator inhibitor (PAI)-1 activity (r = 0.36 and r =
0.29, respectively; P < 0.001). Tissue Plasminogen activator (tPA)
activity correlated inversely to insulin (r = 0.35, P < 0.001) and
proinsulin (r = - 0.36, P < 0.001). In a multivariate analysis taking
also smoking and anthropometric and metabolic measurements into account,
fasting proinsulin was a significant predictor of high plasma fibrinogen
level. Insulin and proinsulin levels were not related to tPA activity. High
levels of postload insulin, triglycerides, and diastolic blood pressure,
but not proinsulin, predicted high PAI-l activity. CONCLUSIONS: In a
healthy population, the relationship previously described between high
insulin levels and impaired fibrinolysis is not attributable to confounding
from proinsulin. Elevated proinsulin levels are associated with high
fibrinogen levels.