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Journal of Obesity
Volume 2010 (2010), Article ID 195729, 7 pages
http://dx.doi.org/10.1155/2010/195729
Research Article

Fitness versus Fatness and Insulin Resistance in U.S. Adolescents

1Brody School of Medicine, East Carolina University, 600 Moye Boulevard, Greenville, NC 27834, USA
2College of Health and Human Performance, East Carolina University, Greenville, NC 27858, USA
3Center for Health Services Research and Development, East Carolina University, Greenville, NC 27858, USA
4Pediatric Healthy Weight Research and Treatment Center, East Carolina University, Greenville, NC 27858, USA

Received 27 May 2009; Revised 11 October 2009; Accepted 13 December 2009

Academic Editor: Andrew P. Hills

Copyright © 2010 Doyle M. Cummings et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background. The present study examined the relationship between insulin resistance and both waist circumference and cardiorespiratory fitness in U.S. adolescents. Methods. NHANES assessed a nationally representative sample of U.S. adolescents (12–18 yrs) between 1999–2002. Abdominal adiposity was estimated by waist circumference, overall adiposity by BMI, and cardiorespiratory fitness (maximal oxygen uptake ( max) from a treadmill exercise test). Insulin resistance was estimated from fasting insulin and glucose using the homeostatic model assessment method (i.e., HOMA) and was log-transformed. Results. 1078 adolescents were included in the study. Positive correlations existed between lnHOMA and waist circumference ( ; ) for boys and girls, respectively. lnHOMA and max were inversely related in boys ( ) but not girls ( ). Gender-specific analyses by BMI category showed that the significant inverse relationship in lnHOMA and max was primarily present in obese boys. Conclusion. Among adolescents, important gender and BMI differences exist in the relationship between insulin resistance and fitness. While waist circumference and BMI are important predictors in all children, fitness appears especially important in obese boys. These findings may have important implications for gender-specific interventions to prevent adult obesity and diabetes mellitus.