High normal fasting glucose level in obese youth: a marker for insulin resistance and beta cell dysregulation.
OBJECTIVE
A high but normal fasting plasma glucose level in adults is a risk factor for future development of type 2 diabetes mellitus and cardiovascular disease. We investigated whether normal fasting plasma glucose levels (<5.60 mmol/l) are associated with decreases in insulin sensitivity and beta cell function, as well as an adverse cardiovascular profile in obese youth.


METHODS
We performed a cross-sectional analysis in a multiethnic sample of 1,020 obese youth (614 girls and 406 boys; mean age 12.9 years [CI 95% 12.7-13.1], BMI z score 2.34 [CI 95% 2.31-2.38]) with normal fasting plasma glucose. All participants had a standard OGTT, with calculation of indices of insulin sensitivity and beta cell function. For the analysis, prepubertal and pubertal participants were stratified into quartiles of normal fasting plasma glucose.


RESULTS
We observed a significant increase in fasting insulin and AUC 2 h glucose across quartiles. Pronounced changes were observed in insulin sensitivity and secretion, particularly in the pubertal group. Moreover, the odds of presenting with impaired glucose tolerance increased by 4.5% with each 0.06 mmol/l increase in fasting plasma glucose. No significant differences in cardiovascular indices were seen across quartiles.


CONCLUSIONS
These data suggest that in obese youth, independent of age, BMI z score, sex, family history and ethnicity, insulin sensitivity and secretion decline when moving from low to high normal fasting plasma glucose. The simple measure of fasting plasma glucose could assist clinicians in identifying children for targeted diabetes screening and subsequent lifestyle management.
O'Malley
G
G
Department of Pediatrics, Yale University School of Medicine, 330 Cedar Street, PO Box 208064, New Haven, CT 06520, USA.
Santoro
N
N
Northrup
V
V
D'Adamo
E
E
Shaw
M
M
Eldrich
S
S
Caprio
S
S
D000293:Adolescent; D000704:Analysis of Variance; D019540:Area Under Curve; D001786:Blood Glucose; D002648:Child; D003430:Cross-Sectional Studies; D005215:Fasting; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D050417:Insulin-Secreting Cells / Q000378:metabolism*; D008297:Male; D009765:Obesity / Q000378:metabolism*; D011237:Predictive Value of Tests; D012044:Regression Analysis; D012307:Risk Factors
D001786:Blood Glucose; D007328:Insulin