Changes in Insulin Sensitivity and Insulin Release in Relation to Glycemia and Glucose Tolerance in 6,414 Finnish Men
Alena Stančáková 1 ,
Martin Javorský 1 ,
Teemu Kuulasmaa 1 ,
Steven M. Haffner 2 ,
Johanna Kuusisto 1 and
Markku Laakso 1
1 Department of Medicine, University of Kuopio and Kuopio University Hospital, Kuopio, Finland; and
2 Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas.
Corresponding author: Markku Laakso, markku.laakso{at}kuh.fi .
A.S. and M.J. contributed equally to the work.
Abstract
OBJECTIVE We evaluated insulin sensitivity and insulin secretion across the entire range of fasting (FPG) and 2-h plasma glucose (PG),
and we investigated the differences in insulin sensitivity and insulin release in different glucose tolerance categories.
RESEARCH DESIGN AND METHODS A total of 6,414 Finnish men (aged 57 ± 7 years, BMI 27.0 ± 3.9 kg/m 2 ) from our ongoing population-based METSIM (Metabolic Syndrome in Men) study were included. Of these subjects, 2,168 had normal
glucose tolerance, 2,859 isolated impaired fasting glucose (IFG), 217 isolated impaired glucose tolerance (IGT), 701 a combination
of IFG and IGT, and 469 newly diagnosed type 2 diabetes.
RESULTS The Matsuda index of insulin sensitivity decreased substantially within the normal range of FPG (−17%) and 2-h PG (−37%)
and was approximately −65 and −53% in the diabetic range of FPG and 2-h PG, respectively, compared with the reference range
(FPG and 2-h PG <5.0 mmol/l). Early-phase insulin release declined by only approximately −5% within the normal range of FPG
and 2-h PG but decreased significantly in the diabetic range of FPG (by 32–70%) and 2-h PG (by 33–51%). Changes in insulin
sensitivity and insulin secretion in relation to hyperglycemia were independent of obesity. The predominant feature of isolated
IGT was impaired peripheral insulin sensitivity. Isolated IFG was characterized by impaired early and total insulin release.
CONCLUSIONS Peripheral insulin sensitivity was already decreased substantially at low PG levels within the normoglycemic range, whereas
impairment in insulin secretion was observed mainly in the diabetic range of FPG and 2-h PG. Obesity did not affect changes
in insulin sensitivity or insulin secretion in relation to hyperglycemia.
Footnotes
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Received November 18, 2008.
Accepted February 9, 2009.
Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work
is not altered. See http://creativecommons.org/licenses/by-nc-nd/3.0/ for details.
© 2009 by the American Diabetes Association....

Changes in Insulin Sensitivity and Insulin Release in Relation to Glycemia and Glucose Tolerance in 6,414 Finnish Men

10.2337/db08-1607