Fitness is a stronger predictor of fasting insulin levels than fatness in overweight male middle-school children.
OBJECTIVE
We studied the relationship between % body fat (%BF), cardiovascular fitness (CVF), and insulin resistance (IR) in overweight middle-school children.


METHODS
Middle school children (n = 106, body mass index [BMI] > 95th percentile for age) underwent evaluation of body composition, maximal volume of oxygen utilization (VO2) uptake/kg lean body mass (VO2max/kgLBM), and fasting glucose and insulin (FI) concentrations and derived homeostasis model assessment index (HOMA(IR)).


RESULTS
Both %BF (r = .33, P < .001) and VO2max/kgLBM (r = -0.42, P < .0001) were significantly correlated with FI. Bivariate regression analysis revealed %BF (P = .008 vs FI, P = .035 vs HOMA(IR)) and VO2max/kgLBM (P < .001 vs FI, P = .009 vs HOMA(IR)) to be independent predictors of insulin sensitivity. In males, VO2max/kgLBM was a better predictor of FI and HOMA(IR) than %BF.


CONCLUSIONS
In obese middle-school children, both %BF and VO2max/kgLBM are independent predictors of FI levels. The relationship between CVF and FI levels was significant in both sexes but was particularly profound and stronger than %BF in males. Efforts to reduce risk of type 2 diabetes mellitus in an increasingly obese child population should include exercise intervention sustained enough to improve CVF.
Allen
David B
DB
Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison 53792, USA. dballen@wisc.edu
Nemeth
Blaise A
BA
Clark
R Randall
RR
Peterson
Susan E
SE
Eickhoff
Jens
J
Carrel
Aaron L
AL
D050154:Adiposity; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D002648:Child; D005215:Fasting; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood*; D007333:Insulin Resistance; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D009765:Obesity / Q000175:diagnosis / Q000378:metabolism*; D010101:Oxygen Consumption; D010809:Physical Fitness; D012737:Sex Factors
D001786:Blood Glucose; D007328:Insulin