title: Reference values for leptin, cortisol, insulin and glucose, among European adolescents and their association with adiposity: the HELENA study.
abstract: OBJECTIVE
  Adequate concentrations of leptin, cortisol, and insulin are important for a suitable metabolism and development during adolescence. These hormones jointly with glucose play a major role in fat metabolism and development of childhood obesity. Our main objective was to quantify biomarkers as leptin, cortisol, insulin and glucose status in European adolescents to contribute to establish reference ranges.
  
  
  METHODS
  A representative sample of 927 adolescents (45% males, 14.9±1.2 years for the overall population) from ten European cities of the HELENA study was used to obtain fasting blood samples for these biomarkers. The percentile distributions were computed by sex and age and percentiles were associated with BMI classification.
  
  
  RESULTS
  Serum leptin concentration in adolescents varied significantly according to BMI, sex and age (all p < 0.001). Cortisol presented a tendency to increase with age, both for females and males, while insulin and glucose were stable with age. Leptin and insulin were highest in obese adolescents (p < 0.001), whilst cortisol and glucose did not vary with BMI. Percentiles 5, 25, 50, 75 and 95, for hormones values were, respectively: 1.27, 4.06, 11.54, 26.70 and 65.33 ng/ml for leptin; 5.00, 8.11, 11.14, 15.00 and 24.51 μg/dl for cortisol and 3.65, 6.15, 8.52, 11.90 and 20.53 μlU/ml for insulin.
  
  
  CONCLUSIONS
  In adolescents, leptin, cortisol, insulin and glucose concentrations are differently affected by age, sex and BMI. Establishment of reference ranges (percentiles) of these biomarkers would be of great interest when pediatricians have to assess the trend of an adolescent to develop obesity years after.
authors.affiliation: ImFINE Research Group. Department of Health and Human Performance. Faculty of Physical Activity and Sport Sciences-INEF. Technical University of Madrid. Spain.. gonzalopalacios88@gmail.com.
authors.forename: Thabata
authors.initials: T
authors.lastname: Koester-Weber
authors.affiliation: ImFINE Research Group. Department of Health and Human Performance. Faculty of Physical Activity and Sport Sciences-INEF. Technical University of Madrid. Spain.. gonzalopalacios88@gmail.com.
authors.forename: Jara
authors.initials: J
authors.lastname: Valtueña
authors.affiliation: ImFINE Research Group. Department of Health and Human Performance. Faculty of Physical Activity and Sport Sciences-INEF. Technical University of Madrid. Spain. Institut für Ernährungs und Lebensmittelwissenschaften Ernährungphysiologie. Rheinische Friedrich Wilhelms Universität, Germany.. gonzalopalacios88@gmail.com.
authors.forename: Christina
authors.initials: C
authors.lastname: Breidenassel
authors.affiliation: Faculté de Médecine, Université de Lille, France.. gonzalopalacios88@gmail.com.
authors.forename: Laurent
authors.initials: L
authors.lastname: Beghin
authors.affiliation: Preventive Medicine and Nutrition Unit, School of Medicine, University of Crete, Heraklion, Crete, Greece.. gonzalopalacios88@gmail.com.
authors.forename: Maria
authors.initials: M
authors.lastname: Plada
authors.affiliation: ImFINE Research Group. Department of Health and Human Performance. Faculty of Physical Activity and Sport Sciences-INEF. Technical University of Madrid. Spain.. gonzalopalacios88@gmail.com.
authors.forename: Sara
authors.initials: S
authors.lastname: Moreno
authors.affiliation: Department of Public Health, Ghent University, Ghent, Belgium. International Agency for Research on Cancer, Dietary Exposure Assessment group, Lyon, France.. gonzalopalacios88@gmail.com.
authors.forename: Inge
authors.initials: I
authors.lastname: Huybrechts
authors.affiliation: ImFINE Research Group. Department of Health and Human Performance. Faculty of Physical Activity and Sport Sciences-INEF. Technical University of Madrid. Spain. CIBERobn (Fisiopatología de la Obesidad y la Nutrición CB12/03/30038), Instituto de Salud Carlos III, Spain.. gonzalopalacios88@gmail.com.
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Palacios
authors.affiliation: Immunonutrition Research Group, Department of Metabolism and Nutrition, Institute of Food Science, Technology and Nutrition (ICTAN), Spanish National Research Council (CSIC), Madrid, Spain.. gonzalopalacios88@gmail.com.
authors.forename: Sonia
authors.initials: S
authors.lastname: Gómez-Martínez
authors.affiliation: ImFINE Research Group. Department of Health and Human Performance. Faculty of Physical Activity and Sport Sciences-INEF. Technical University of Madrid. Spain.. gonzalopalacios88@gmail.com.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Albers
authors.affiliation: Department of Public Health, Ghent University, Ghent, Belgium.. gonzalopalacios88@gmail.com.
authors.forename: Stefaan
authors.initials: S
authors.lastname: De Henauw
authors.affiliation: Food & Nutrition Research Centre, Agricultural Research Council (CRA-NUT), Rome, Italy.. gonzalopalacios88@gmail.com.
authors.forename: Guiseppe
authors.initials: G
authors.lastname: Maiani
authors.affiliation: Preventive Medicine and Nutrition Unit, School of Medicine, University of Crete, Heraklion, Crete, Greece.. gonzalopalacios88@gmail.com.
authors.forename: Anthony
authors.initials: A
authors.lastname: Kafatos
authors.affiliation: Department of Pediatrics, University of Pécs, Pécs, József A. u. 7, 7623 Pécs, Hungary.. gonzalopalacios88@gmail.com.
authors.forename: Denes
authors.initials: D
authors.lastname: Molnar
authors.affiliation: Karolinska Institute, Sweden.. gonzalopalacios88@gmail.com.
authors.forename: Michael
authors.initials: M
authors.lastname: Sjöstrom
authors.affiliation: Department of Pediatrics, Private Medical University, Strubergasse 21, 5020 Salzburg, Austria.. gonzalopalacios88@gmail.com.
authors.forename: Kurt
authors.initials: K
authors.lastname: Widhalm
authors.affiliation: Department of Nutrition & Dietetics, Harokopio University, 70, El Venizelou Ave, 176 71 Kallithea, Athens - Greece.. gonzalopalacios88@gmail.com.
authors.forename: Yannis
authors.initials: Y
authors.lastname: Manios
authors.affiliation: Growth, Exercise, Nutrition and Development (GENUD) Research Group, Faculty of Health Sciences, University of Zaragoza, Domingo Miral s/n, 50009 Zaragoza, Spain.. gonzalopalacios88@gmail.com.
authors.forename: Luis A
authors.initials: LA
authors.lastname: Moreno
authors.affiliation: Immunonutrition Research Group, Department of Metabolism and Nutrition, Institute of Food Science, Technology and Nutrition (ICTAN), Spanish National Research Council (CSIC), Madrid, Spain.. gonzalopalacios88@gmail.com.
authors.forename: Ascensión
authors.initials: A
authors.lastname: Marcos
authors.affiliation: Department of Medical Physiology, School of Medicine, University of Granada, Spain.. gonzalopalacios88@gmail.com.
authors.forename: Manuel J
authors.initials: MJ
authors.lastname: Castillo
authors.affiliation: Institut für Ernährungs und Lebensmittelwissenschaften Ernährungphysiologie. Rheinische Friedrich Wilhelms Universität, Germany.. gonzalopalacios88@gmail.com.
authors.forename: Peter
authors.initials: P
authors.lastname: Stehle
authors.affiliation: ImFINE Research Group. Department of Health and Human Performance. Faculty of Physical Activity and Sport Sciences-INEF. Technical University of Madrid. Spain. CIBERobn (Fisiopatología de la Obesidad y la Nutrición CB12/03/30038), Instituto de Salud Carlos III, Spain.. gonzalopalacios88@gmail.com.
authors.forename: Marcela
authors.initials: M
authors.lastname: Gonzalez-Gross
mesh_terms: D050154:Adiposity / Q000502:physiology*; D000293:Adolescent; D001786:Blood Glucose / Q000032:analysis*; D005060:Europe; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D007328:Insulin / Q000097:blood*; D020738:Leptin / Q000097:blood*; D008297:Male; D012016:Reference Values; D044465:White People
chemical_list: D001786:Blood Glucose; D007328:Insulin; D020738:Leptin; D006854:Hydrocortisone