Cardiorespiratory fitness, waist circumference and liver enzyme levels in European adolescents: The HELENA cross-sectional study

María Medrano, Idoia Labayen, Jonatan R. Ruiz, Gerardo Rodríguez, Christina Breidenassel, Manuel Castillo, Raquel Pedrero, Kurt Widhalm, Anthony Kafatos, Yannis Manios, D. Molnár, Marcela González-Gross, Francisco B. Ortega, Luis A. Moreno

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Objectives (1) To examine whether cardiorespiratory fitness (CRF) is related to liver enzyme levels independent of waist circumference (WC), and (2) To test whether having a high CRF is associated with an improved liver enzyme profile with a high WC. Design Cross-sectional. Methods CRF (20 m-shuttle-run test) and WC were assessed in 811 European adolescents (48.5% males) aged 12.5–17.5 years. Fatty liver biomarkers included fasting serum alanine-aminotransferase (ALT), gamma-glutamyl-transpeptidase (GGT) and the aspartate-aminotransferase to ALT (AST/ALT) ratio. Participants were categorized as fit or unfit (CRF below or above 43.8 mL/kg/min and 34.6 mL/kg/min, for boys and girls, respectively) and as high or non-high WC (sex and age-specific cut-offs). Results CRF was associated with ALT (β = −0.106; p = 0.049) and GGT levels (β = −0.225; p < 0.001) and AST/ALT ratio (β = 0.234; p < 0.001), yet these relationships were attenuated after further controlling for WC (all p > 0.1). High WC and fit adolescents had lower ALT levels (28 ± 1 U/L vs. 23 ± 2 U/L, unfit and fit respectively, p = 0.018) and higher AST/ALT ratio (0.94 ± 0.04 vs. 1.10 ± 0.06, unfit and fit respectively, p = 0.010) than those who were high WC but unfit. Conclusions The results showed that CRF is not independently associated with liver enzymes, and that WC is a stronger predictor in adolescents. These findings also suggest that high CRF may have specific protective effects on liver enzyme levels in adolescents with high WC. Exercise programs focused on increasing CRF and decreasing abdominal adiposity could be a good alternative in the treatment and prevention of obesity related fatty liver disease in adolescents.

Original languageEnglish
Pages (from-to)932-936
Number of pages5
JournalJournal of Science and Medicine in Sport
Issue number10
Publication statusPublished - Oct 1 2017



  • Adolescents
  • Alanine-aminotransferase
  • Fitness
  • Nonalcoholic fatty liver disease
  • Obesity
  • Waist circumference

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

Cite this

Medrano, M., Labayen, I., Ruiz, J. R., Rodríguez, G., Breidenassel, C., Castillo, M., Pedrero, R., Widhalm, K., Kafatos, A., Manios, Y., Molnár, D., González-Gross, M., Ortega, F. B., & Moreno, L. A. (2017). Cardiorespiratory fitness, waist circumference and liver enzyme levels in European adolescents: The HELENA cross-sectional study. Journal of Science and Medicine in Sport, 20(10), 932-936.