Prevalence of impaired glucose tolerance among children and adolescents with marked obesity.
BACKGROUND
Childhood obesity, epidemic in the United States, has been accompanied by an increase in the prevalence of type 2 diabetes among children and adolescents. We determined the prevalence of impaired glucose tolerance in a multiethnic cohort of 167 obese children and adolescents.


METHODS
All subjects underwent a two-hour oral glucose-tolerance test (1.75 g [DOSAGE ERROR CORRECTED] of glucose per kilogram of body weight), and glucose, insulin, and C-peptide levels were measured. Fasting levels of proinsulin were obtained, and the ratio of proinsulin to insulin was calculated. Insulin resistance was estimated by homeostatic model assessment, and beta-cell function was estimated by calculating the ratio between the changes in the insulin level and the glucose level during the first 30 minutes after the ingestion of glucose.


RESULTS
Impaired glucose tolerance was detected in 25 percent of the 55 obese children (4 to 10 years of age) and 21 percent of the 112 obese adolescents (11 to 18 years of age); silent type 2 diabetes was identified in 4 percent of the obese adolescents. Insulin and C-peptide levels were markedly elevated after the glucose-tolerance test in subjects with impaired glucose tolerance but not in adolescents with diabetes, who had a reduced ratio of the 30-minute change in the insulin level to the 30-minute change in the glucose level. After the body-mass index had been controlled for, insulin resistance was greater in the affected cohort and was the best predictor of impaired glucose tolerance.


CONCLUSIONS
Impaired glucose tolerance is highly prevalent among children and adolescents with severe obesity, irrespective of ethnic group. Impaired oral glucose tolerance was associated with insulin resistance while beta-cell function was still relatively preserved. Overt type 2 diabetes was linked to beta-cell failure.
Sinha
Ranjana
R
Department of Pediatrics, Yale University School of Medicine, New Haven, Conn 06520, USA.
Fisch
Gene
G
Teague
Barbara
B
Tamborlane
William V
WV
Banyas
Bruna
B
Allen
Karin
K
Savoye
Mary
M
Rieger
Vera
V
Taksali
Sara
S
Barbetta
Gina
G
Sherwin
Robert S
RS
Caprio
Sonia
S
D000293:Adolescent; D044383:Black People; D001786:Blood Glucose / Q000378:metabolism; D002096:C-Peptide / Q000097:blood; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D003920:Diabetes Mellitus / Q000453:epidemiology* / Q000378:metabolism; D005260:Female; D005947:Glucose / Q000378:metabolism*; D005951:Glucose Tolerance Test; D006630:Hispanic or Latino; D006801:Humans; D007328:Insulin / Q000097:blood / Q000378:metabolism; D000078790:Insulin Secretion; D008297:Male; D009765:Obesity / Q000097:blood / Q000208:ethnology / Q000378:metabolism*; D015995:Prevalence; D011384:Proinsulin / Q000097:blood; D012307:Risk Factors; D044465:White People
D001786:Blood Glucose; D002096:C-Peptide; D007328:Insulin; D011384:Proinsulin; D005947:Glucose