title: Physical activity, sedentary time, and liver enzymes in adolescents: the HELENA study.
abstract: BACKGROUND
  To examine the association between physical activity (PA) and liver enzyme levels in adolescents from nine European countries.
  
  
  METHODS
  The study comprised 718 adolescents (397 girls). PA was measured by accelerometry and expressed as total PA (counts/min), and time (min/d) engaged in moderate to vigorous intensity PA (MVPA). Time spent sedentary was also objectively measured. We measured serum levels of alanine aspartate aminotransferase (AST), alanine aminotransferase (ALT), and γ-glutamyltransferase (GGT), and the AST/ALT ratio was computed.
  
  
  RESULTS
  There was an association between MVPA and AST and AST/ALT (age, sex, and center-adjusted β = 0.096, 95% confidence interval (CI): 0.016 to 0.118; and β = 0.090, 95% CI: 0.006 to 0.112, respectively). Meeting the PA recommendations (60 min/d of MVPA) was significantly associated with higher AST and AST/ALT, which persisted after further adjusting for sedentary time and waist circumference. Sedentary time was not associated with any of the studied liver enzyme levels.
  
  
  CONCLUSIONS
  Meeting the current PA recommendations of 60 min/d of MVPA is associated with higher levels of AST and AST/ALT regardless of time spent sedentary as well as total and central body fat in European adolescents.
authors.affiliation: 1] PROFITH "PROmoting FITness and Health through physical activity" Research Group, Department of Physical Education and Sports, Faculty of Sport Sciences, University of Granada, Granada, Spain [2] Department of Biosciences and Nutrition at NOVUM, Unit for Preventive Nutrition, Karolinska Institutet, Huddinge, Sweden.
authors.forename: Jonatan R
authors.initials: JR
authors.lastname: Ruiz
authors.affiliation: 1] Department of Nutrition and Food Science, University of the Basque Country, Vitoria, Spain [2] GENUD "Growth, Exercise, Nutrition and Development" Research Group, Zaragoza, Spain.
authors.forename: Idoia
authors.initials: I
authors.lastname: Labayen
authors.affiliation: 1] PROFITH "PROmoting FITness and Health through physical activity" Research Group, Department of Physical Education and Sports, Faculty of Sport Sciences, University of Granada, Granada, Spain [2] Department of Biosciences and Nutrition at NOVUM, Unit for Preventive Nutrition, Karolinska Institutet, Huddinge, Sweden.
authors.forename: Francisco B
authors.initials: FB
authors.lastname: Ortega
authors.affiliation: 1] GENUD "Growth, Exercise, Nutrition and Development" Research Group, Zaragoza, Spain [2] Department of Health and Human Performance, School of Health Sciences, University of Zaragoza, Zaragoza, Spain.
authors.forename: Luis A
authors.initials: LA
authors.lastname: Moreno
authors.affiliation: 1] GENUD "Growth, Exercise, Nutrition and Development" Research Group, Zaragoza, Spain [2] Department of Pediatrics, University of Zaragoza, Zaragoza, Spain.
authors.forename: Gerardo
authors.initials: G
authors.lastname: Rodriguez
authors.affiliation: Institut für Ernährungs und Lebensmittelwissenschaften - Humanernährung, Rheinische Friedrich-Wilhelms Universität Bonn, Bonn, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Breidenassel
authors.affiliation: Department of Nutrition and Dietetics, Harokopio University, Athens, Greece.
authors.forename: Yannis
authors.initials: Y
authors.lastname: Manios
authors.affiliation: Preventive Medicine and Nutrition Unit, School of Medicine, University of Crete, Crete, Greece.
authors.forename: Anthony
authors.initials: A
authors.lastname: Kafatos
authors.affiliation: Department of Pediatrics, University of Pecs, Pecs, Hungary.
authors.forename: Denes
authors.initials: D
authors.lastname: Molnar
authors.affiliation: Department of Public Health, Ghent University, Ghent, Belgium.
authors.forename: Stephaan
authors.initials: S
authors.lastname: De Henauw
authors.affiliation: INSERM U995, Faculté de Médecine, University of Lille, Lille, France.
authors.forename: Frederic
authors.initials: F
authors.lastname: Gottrand
authors.affiliation: Department of Pediatrics, Division of Clinical Nutrition, Medical University of Vienna, Vienna, Austria.
authors.forename: Kurt
authors.initials: K
authors.lastname: Widhalm
authors.affiliation: Department of Medical Physiology, School of Medicine, University of Granada, Granada, Spain.
authors.forename: Manuel J
authors.initials: MJ
authors.lastname: Castillo
authors.affiliation: Department of Biosciences and Nutrition at NOVUM, Unit for Preventive Nutrition, Karolinska Institutet, Huddinge, Sweden.
authors.forename: Michael
authors.initials: M
authors.lastname: Sjöström
mesh_terms: D061725:Accelerometry; D000273:Adipose Tissue / Q000502:physiology; D000293:Adolescent; D000410:Alanine Transaminase / Q000097:blood; D001219:Aspartate Aminotransferases / Q000097:blood; D005060:Europe; D005260:Female; D006801:Humans; D008099:Liver / Q000201:enzymology*; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D012044:Regression Analysis; D057185:Sedentary Behavior; D005723:gamma-Glutamyltransferase / Q000097:blood
chemical_list: D005723:gamma-Glutamyltransferase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase