In Nonobese Children, Fitness and BMI are Independent Predictors of Fasting Insulin

Objective: Although fitness and obesity have been shown to be independent predictors of cardiometabolic disease risk in obese children, this interaction is not well defined in nonobese children. The purpose of this study was to define the relationships between peak aerobic capacity, body composition, and fasting insulin levels in nonobese middle school children. Study Design: 148 middle school children (mean age 11.0 ± 2.1 years, 49% male) underwent determination of body mass index (BMI) z-score, fasting glucose, fasting insulin, body composition by DXA scan (lean body mass and body fat percentage), and peak oxygen uptake per kg of lean body mass (VO2peak). Univariate correlations and multivariate regression analysis were used to identify independent predictors of fasting insulin using age, sex, percent body fat, body mass index z-score, and VO2peak. Results: fasting insulin was significantly related to VO2peak (r =−0.37, p < .001), percent body fat (r = .27, p < .001), and BMI z-score (r = .33, p = .002)...