title: Mechanisms of stress, energy homeostasis and insulin resistance in European adolescents--the HELENA study.
abstract: OBJECTIVE
  Stress is hypothesized to facilitate the development of obesity, whose the foundations are already set during childhood and adolescence. We investigated the relationship between the stress-system, selected mechanisms of energy homeostasis and insulin resistance (IR) in a sample of European adolescents.
  
  
  RESULTS
  Within HELENA-CSS, 723 adolescents (12.5-17.5 years) from 10 European cities provided all the necessary data for this study. Fasting blood samples were collected for cortisol, leptin, insulin and glucose analysis. HOMA-IR was calculated from insulin and glucose concentrations. Adolescents' body fat (BF) %, age and duration of exclusive breastfeeding were assessed. For boys and girls separately, the relationship of cortisol with leptin, insulin, glucose and HOMA-IR was examined by computing Pearson correlation coefficients and Hierarchical Linear Models (HLMs), with 'city' as cluster unit, adjusting for age, BF% and duration of exclusive breastfeeding. In boys, Pearson correlation coefficients illustrated positive correlations of cortisol with insulin (r = 0.144; p = 0.013), glucose (r = 0.315; p < 0.001) and HOMA-IR (r = 0.180; p = 0.002), whilst in girls, this positive relationship was observed for leptin (r = 0.147; p = 0.002), insulin (r = 0.095; p = 0.050) and HOMA-IR (r = 0.099; p = 0.041), but not for glucose (r = 0.054; p = 0.265). Observed associations were independent of adolescents' age, BF% and duration of exclusive breastfeeding after computing HLMs.
  
  
  CONCLUSIONS
  This study suggests that the stress-system is positively related to mechanisms of energy homeostasis and IR in European adolescents, and reveals a potential small gender difference in this relationship. The hypothesis that stress might facilitate the development of obesity during adolescence is supported.
authors.affiliation: Department of Public Health, Ghent University, Ghent, Belgium; International Agency for Research on Cancer, Dietary Exposure Assessment Group, Lyon, France. Electronic address: inge.huybrechts@ugent.be.
authors.forename: I
authors.initials: I
authors.lastname: Huybrechts
authors.affiliation: Department of Public Health, Ghent University, Ghent, Belgium; Research Foundation Flanders, Brussels, Belgium.
authors.forename: T
authors.initials: T
authors.lastname: De Vriendt
authors.affiliation: ImFINE Research Group, Department of Health and Human Performance, Universidad Politécnica de Madrid, Spain; Department of Human Nutrition, Rheinische Friedrich-Wilhemls Universität, Bonn, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Breidenassel
authors.affiliation: Department of Public Health, Ghent University, Ghent, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Rogiers
authors.affiliation: Department of Public Health, Ghent University, Ghent, Belgium; Research Foundation Flanders, Brussels, Belgium.
authors.forename: B
authors.initials: B
authors.lastname: Vanaelst
authors.affiliation: Department of Medical Physiology, School of Medicine, Granada University, Granada, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Cuenca-García
authors.affiliation: Growth, Exercise, Nutrition and Development (GENUD) Research Group, School of Health Science (EUCS), University of Zaragoza, Zaragoza, Spain.
authors.forename: L A
authors.initials: LA
authors.lastname: Moreno
authors.affiliation: ImFINE Research Group, Department of Health and Human Performance, Universidad Politécnica de Madrid, Spain; Department of Human Nutrition, Rheinische Friedrich-Wilhemls Universität, Bonn, Germany.
authors.forename: M
authors.initials: M
authors.lastname: González-Gross
authors.affiliation: Istituto Nazionale di Ricerca per gli Alimenti e la Nutrizione (INRAN), Roma, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Roccaldo
authors.affiliation: Department of Social Medicine, School of Medicine, Preventive Medicine and Nutrition Clinic, University of Crete, Crete, Greece.
authors.forename: A
authors.initials: A
authors.lastname: Kafatos
authors.affiliation: Department of Public Health, Ghent University, Ghent, Belgium.
authors.forename: E
authors.initials: E
authors.lastname: Clays
authors.affiliation: Growth, Exercise, Nutrition and Development (GENUD) Research Group, School of Health Science (EUCS), University of Zaragoza, Zaragoza, Spain.
authors.forename: G
authors.initials: G
authors.lastname: Bueno
authors.affiliation: Inserm U955, IFR114, Faculty of Medicine, University Lille 2, Lille, France; CIC-9301-CH&U-Inserm of Lille, CHRU de Lille, Lille, France.
authors.forename: L
authors.initials: L
authors.lastname: Beghin
authors.affiliation: Unit for Preventive Nutrition, Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Sjöstrom
authors.affiliation: Department of Nutrition & Dietetics, Harokopio University, Athens, Greece.
authors.forename: Y
authors.initials: Y
authors.lastname: Manios
authors.affiliation: Department of Pediatrics, Medical Faculty, University of Pécs, Jzsef A 7, Pécs, Hungary.
authors.forename: D
authors.initials: D
authors.lastname: Molnár
authors.affiliation: International Agency for Research on Cancer, Dietary Exposure Assessment Group, Lyon, France; MRC/Wits Developmental Pathways for Health Research Unit, Department of Paediatrics, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
authors.forename: P T
authors.initials: PT
authors.lastname: Pisa
authors.affiliation: Department of Public Health, Ghent University, Ghent, Belgium; University College Ghent Vesalius, Ghent, Belgium.
authors.forename: S
authors.initials: S
authors.lastname: De Henauw
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D000293:Adolescent; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D002648:Child; D003430:Cross-Sectional Studies; D005060:Europe; D005260:Female; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology*; D020738:Leptin / Q000097:blood; D008297:Male; D009765:Obesity / Q000097:blood; D012959:Socioeconomic Factors; D013315:Stress, Psychological / Q000097:blood*; D044465:White People
chemical_list: D001786:Blood Glucose; D007328:Insulin; D020738:Leptin; D006854:Hydrocortisone
keywords: Adolescents; Cortisol; Energy homeostasis; Glucose; HOMA-IR; Insulin; Leptin; Stress