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Improvements in Fitness Reduce the Risk of Becoming Overweight across Puberty


Medicine & Science in Sports & Exercise: October 2011 - Volume 43 - Issue 10 - pp 1891-1897
doi: 10.1249/MSS.0b013e3182190d71

Purpose: Information about factors related to overweight development in early stages of life is needed for designing useful strategies to prevent overweight and related diseases. Longitudinal studies can contribute to this goal. The present study aimed to identify factors in childhood that determine the development of overweight/obesity in adolescence.

Methods: A prospective study in 598 normal-weight Estonian and Swedish children age 9.5 ± 0.4 yr from the European Youth Heart Study, who were followed during 6 yr, was conducted. Weight and height were measured at baseline and follow-up, and weight status was ascertained according to the international criteria for body mass index. Cardiorespiratory fitness (expressed as V˙O2max (mL·kg−1·min−1)) was assessed by a maximal bike test. Parents reported their weight, height, and educational level.

Results: Being male (vs female) and Estonian (vs Swedish) was related to higher risk for incident overweight/obesity. Change in fitness was a stronger predictor of incident overweight/obesity than childhood fitness, parental overweight, or parental education. The risk of developing overweight/obesity was reduced 10% every 1 mL·kg−1·min−1 of V˙O2max increase (odds ratio = 0.90 and 95% confidence interval = 0.84-0.95) after adjustment for a set of confounders including baseline body mass index and without differences by gender.

Conclusions: Our results suggest that improvements in fitness from childhood to adolescence are associated with a lower risk of becoming overweight/obese in adolescence. The current findings highlight the importance of promoting fitness through physical exercise from early stages in life, as a promising strategy to fight against overweight and obesity. Gender and country differences observed in this study require social and political attention.

1Unit for Preventive Nutrition, Department of Biosciences and Nutrition at NOVUM, Karolinska Institutet, Huddinge, SWEDEN; 2Department of Medical Physiology, School of Medicine, University of Granada, Granada, SPAIN; 3Department of Nutrition and Food Science, University of the Basque Country, Vitoria, SPAIN; 4Department of Physical Activity and Sport, School of Physical Activity and Sport Sciences, University of Granada, Granada, SPAIN; 5Department Chronic Diseases, National Institute for Health Development, Estonian Centre of Behavioral and Health Sciences, Tallinn, ESTONIA; 6Department of Psychology, University of Tartu, Estonian Centre of Behavioral and Health Sciences, Tartu, ESTONIA; and 7National Institute for Health Development, Estonian Centre of Behavioral and Health Sciences, Tallinn, ESTONIA

Address for correspondence: Francisco B. Ortega, Department of Biosciences and Nutrition at NOVUM, Karolinska Institutet, SE-14183 Huddinge, Sweden; E-mail:

Submitted for publication December 2010.

Accepted for publication March 2011.

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©2011The American College of Sports Medicine