Reliable Prediction of Insulin Resistance by a School-Based Fitness Test in Middle-School Children

Abstract

<p/> <p><it>Objectives</it>. (1) Determine the predictive value of a school-based test of cardiovascular fitness (CVF) for insulin resistance (IR); (2) compare a "school-based" prediction of IR to a "laboratory-based" prediction, using various measures of fitness and body composition. <it>Methods</it>. Middle school children (<inline-formula><graphic file="1687-9856-2009-487804-i1.gif"/></inline-formula>) performed the Progressive Aerobic Cardiovascular Endurance Run (PACER), a school-based CVF test, and underwent evaluation of maximal oxygen consumption treadmill testing (<inline-formula><graphic file="1687-9856-2009-487804-i2.gif"/></inline-formula> max), body composition (percent body fat and BMI <it>z</it> score), and IR (derived homeostasis model assessment index [<inline-formula><graphic file="1687-9856-2009-487804-i3.gif"/></inline-formula>]). <it>Results</it>. PACER showed a strong correlation with <inline-formula><graphic file="1687-9856-2009-487804-i4.gif"/></inline-formula> max/kg (<inline-formula><graphic file="1687-9856-2009-487804-i5.gif"/></inline-formula> = 0.83, <inline-formula><graphic file="1687-9856-2009-487804-i6.gif"/></inline-formula>) and with <inline-formula><graphic file="1687-9856-2009-487804-i7.gif"/></inline-formula> (<inline-formula><graphic file="1687-9856-2009-487804-i8.gif"/></inline-formula> = <inline-formula><graphic file="1687-9856-2009-487804-i9.gif"/></inline-formula>, <inline-formula><graphic file="1687-9856-2009-487804-i10.gif"/></inline-formula>). Multivariate regression analysis revealed that a school-based model (using PACER and BMI <it>z</it> score) predicted IR similar to a laboratory-based model (using <inline-formula><graphic file="1687-9856-2009-487804-i11.gif"/></inline-formula> max/kg of lean body mass and percent body fat). <it>Conclusions</it>. The PACER is a valid school-based test of CVF, is predictive of IR, and has a similar relationship to IR when compared to complex laboratory-based testing. Simple school-based measures of childhood fitness (PACER) and fatness (BMI <it>z</it> score) could be used to identify childhood risk for IR and evaluate interventions.</p>