Insulin sensitivity from preschool to school age in patients with severe obesity.
BACKGROUND
Insulin sensitivity decreases at puberty transition, but little information has been provided on its earlier time-course. Aim of the present study was to describe the time-course of insulin sensitivity in severely obese children at the transition from preschool to school age.


METHODS
Retrospective study of a cohort of 47 severely obese [Body Mass Index (BMI) ≥99° percentile] preschoolers evaluated twice, once between 2 and 6 years of age, and once before age 8. Glucose tolerance, Whole Body Insulin Sensitivity Index (WBISI), Insulinogenic Index (IGI); β-cell demand index (BCDI) and Insulin Secretion-Sensitivity Index 2 (ISSI-2) were longitudinally estimated during the oral glucose tolerance test.


RESULTS
After a median follow-up of 2.23 (1-4.52) y, obese patients showed significant decrease in WBISI (p<0.0001), and increase in fasting (p = 0.005) and 2 h glucose (2HG, p = 0.001). One child in preschool age and 4 school age children presented with 2HG between 7.8-11.1 mmol/l. Best predictors of WBISI, 2HG and BCDI in the school age were changes in BMI z-score (R(2) = 0.309; p = 0.002; β = -0.556), ISSI-2 (R(2) = 0.465; p<0.0001; β = -0.682), and BMI z-score (R(2) = 0.246; p = 0.008; 0.496), respectively.


CONCLUSIONS
In morbidly obese children, insulin sensitivity seems to decline even before pubertal transition, but changes in total adiposity can only partially explain this variation.
Scientific Directorate, Research Unit for Multifactorial Disease, Bambino Gesù Children Hospital, Rome, Italy. melania.manco@opbg.net
Melania
M
Manco
Maria Rita
MR
Spreghini
Rosa
R
Luciano
Cecilia
C
Pensini
Rita Wietrzycowska
RW
Sforza
Carmela
C
Rustico
Marco
M
Cappa
Giuseppe Stefano
GS
Morino
D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D002648:Child; D002675:Child, Preschool; D005215:Fasting / Q000097:blood; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D016014:Linear Models; D008055:Lipids / Q000097:blood; D008297:Male; D009767:Obesity, Morbid / Q000097:blood* / Q000503:physiopathology*; D011627:Puberty / Q000502:physiology; D012189:Retrospective Studies; D013997:Time Factors
D001786:Blood Glucose; D007328:Insulin; D008055:Lipids