Association between insulin sensitivity and post-glucose challenge plasma insulin values in overweight Latino youth.
OBJECTIVE
To determine associations between directly measured insulin sensitivity (SI) and oral glucose tolerance test (OGTT)-derived plasma insulin values, or calculated SI indices, in overweight peripubertal Latino children at risk for type 2 diabetes.


METHODS
Thirty overweight Latino children with a family history of type 2 diabetes, aged 8-13 years, Tanner stages 1-2, underwent an OGTT. Fasting and 2-h plasma insulin values and OGTT-derived SI indices were compared with SI derived from a frequently sampled intravenous glucose tolerance test (FSIGTT) with minimal model analysis, before and after adjustment for total body fat and lean tissue mass, or BMI.


RESULTS
FSIGTT-derived SI for all subjects was 1.62 +/- 0.78 x 10(-4) min (-1) x (microU/ml), with no sex differences. SI correlated (all P values < 0.001) with fasting (r = -0.57) and 2-h (r = -0.58) plasma insulin and all SI indices (r = -0.57 to 0.67). After adjusting for total body fat and lean tissue mass, or BMI, the associations between SI and either fasting insulin or fasting SI indices were no longer significant. However, the 2-h insulin and post-glucose challenge SI indices maintained significant independent associations with SI, even after adjustment for body composition.


CONCLUSIONS
In overweight, peripubertal Latino children at risk for type 2 diabetes, the 2-h plasma insulin value and postchallenge SI indices are better independent correlates of SI than fasting values, after accounting for body composition. The 2-h insulin may therefore be superior to fasting insulin as a single blood sample value for clinical or epidemiological estimates of SI, especially when combined with assessment of body composition.
Weigensberg
Marc J
MJ
Department of Physiology and Biophysics, University of Southern California, Los Angeles, California 90089, USA.
Cruz
Martha L
ML
Goran
Michael I
MI
D000273:Adipose Tissue / Q000033:anatomy & histology; D001786:Blood Glucose / Q000378:metabolism*; D001823:Body Composition; D015992:Body Mass Index; D002648:Child; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics; D005190:Family; D005215:Fasting; D005260:Female; D005951:Glucose Tolerance Test; D006630:Hispanic or Latino; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D009765:Obesity / Q000097:blood / Q000503:physiopathology*
D001786:Blood Glucose; D007328:Insulin