Relationship between body mass index and insulin measured during oral glucose tolerance testing in severely obese children and adolescents.
OBJECTIVE
The study evaluated the accuracy of body mass index (BMI) in detecting hyperinsulinaemia during oral glucose tolerance testing (OGTT) in severely obese children.


METHODS
A cross-sectional study was carried out.


METHODS
A total of 118 obese children and adolescents (49 females and 69 males) aged 6-19 years were consecutively studied at an outpatient paediatric clinic. Hyperinsulinaemia was defined as a value of log-transformed fasting insulin >/= 80th percentile and OGTT hyperinsulinaemia as a value of the log-transformed area under the curve (AUC) of insulin >/= 80th percentile. The study hypothesis was tested using a logistic regression model with hyperinsulinaemia as the outcome variable and the z-score of BMI corrected for age (z-BMI(age)) as the predictor variable. Receiver-operator characteristic (ROC) curves were used to evaluate accuracy.


RESULTS
The mean (SD) BMI for age of the children was 28.6 (4.0) kg m(-2), corresponding to 2.2 (0.5) standard deviation scores. The odds ratio (OR) of OGTT hyperinsulinaemia was 2.0 (95% CI 1.2-3.3; p = 0.007) for each unit increase of z-BMI(age) and the corresponding ROC-AUC was 0.74 (95% CI 0.61-0.86; p = 0.0001). In comparison, the OR of fasting hyperinsulinaemia was 1.1 (95% CI 0.7-1.7; p = 0.716) for each unit increase of z-BMI(age) and the corresponding ROC-AUC was 0.49 (95% CI 0.35-0.62; p = 0.863).


CONCLUSIONS
BMI is reasonably accurate in detecting OGTT hyperinsulinaemia in severely obese children.
Iughetti
L
L
Paediatrics Clinic, University of Modena and Reggio Emilia, Italy.
De Simone
M
M
Bernasconi
S
S
Predieri
B
B
Battistini
N
N
Bedogni
G
G
D000293:Adolescent; D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D015992:Body Mass Index; D002648:Child; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D006946:Hyperinsulinism / Q000097:blood*; D008297:Male; D009765:Obesity / Q000097:blood*
D001786:Blood Glucose