Alternative methods of insulin sensitivity assessment in obese children and adolescents.
OBJECTIVE
To validate fasting indexes against minimal model analysis (MMOD) of the frequently sampled intravenous glucose tolerance test (FSIVGTT) in an obese pediatric population.


METHODS
FSIVGTT-MMOD results were compared with homeostasis model assessment of insulin resistance (HOMA-IR) and fasting insulin with the sample stratified by sex, puberty, and sensitivity index (S(i)) median in 191 children (82 males and 109 females, 13.9 +/- 2.9 years of age, BMI 36.9 +/- 6.2 kg/m(2), BMI SD score 6.1 +/- 1.6).


RESULTS
Across pubertal groups, correlation coefficients between S(i) and HOMA-IR ranged from -0.43 to -0.78 in males and from -0.53 to -0.57 in females (age and BMI adjusted, P < 0.05 in all instances). Similar results were seen for fasting insulin. In females, the relationship was significantly weaker in more-insulin-resistant subjects.


CONCLUSIONS
The validity of fasting indexes in explaining S(i) was sex dependent, varied with pubertal stage, and in females was influenced by degree of insulin sensitivity. In obese pediatric populations, we generally discourage the use of fasting indexes, although the validity varies within subgroups.
Rössner
Sophia M
SM
Division of Pediatrics, Department of Woman and Child Health, Karolinska Institute, Stockholm, Sweden. sophia.rossner@karolinska.se
Neovius
Martin
M
Montgomery
Scott M
SM
Marcus
Claude
C
Norgren
Svante
S
D015502:Absorptiometry, Photon; D000293:Adolescent; D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood*; D007333:Insulin Resistance; D008297:Male; D009765:Obesity / Q000097:blood*; D050177:Overweight / Q000097:blood*
D001786:Blood Glucose; D007328:Insulin