title: Reference values for leptin and adiponectin in children below the age of 10 based on the IDEFICS cohort.
abstract: OBJECTIVE
  To establish age- and sex-specific reference values for serum leptin and adiponectin in normal-weight 3.0-8.9-year old European children.
  
  
  METHODS
  Blood samples for hormone analysis were taken from 1338 children of the IDEFICS (Identification and prevention of Dietary- and lifestyle-induced health Effects in Children and infantS) study cohort. Only normal-weight children aged 3.0-8.9 years were included (n=539) in our analysis. Using the General Additive Model for Location Scale and Shape, age- and sex-specific percentiles were derived. The influence of under/overweight and obesity on the proposed reference curves based on normal-weight children was investigated in several sensitivity analyses using the sample without obese children (n=1015) and the whole study sample (n=1338).
  
  
  RESULTS
  There was a negative age trend of adiponectin blood levels and a positive trend of leptin levels in boys and girls. Percentiles derived for girls were generally higher than those obtained for boys. The corresponding age-specific differences of the 97th percentile ranged from -2.2 to 4.6 μg ml(-1) and from 2.2 to 4.8 ng ml(-1) for adiponectin and leptin, respectively.
  
  
  CONCLUSIONS
  According to our knowledge, these are the first reference values of leptin and adiponectin in prepubertal, normal-weight children. The presented adiponectin and leptin reference curves may allow for a more differentiated interpretation of children's hormone levels in epidemiological and clinical studies.
authors.affiliation: Department of Paediatrics, University of Pécs, Pécs, Hungary.
authors.forename: E
authors.initials: E
authors.lastname: Erhardt
authors.affiliation: Leibniz Institute for Prevention Research and Epidemiology-BIPS, Bremen, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Foraita
authors.affiliation: 1] Leibniz Institute for Prevention Research and Epidemiology-BIPS, Bremen, Germany [2] Institute of Statistics, Faculty of Mathematics and Computer Science, Bremen University, Bremen, Germany.
authors.forename: I
authors.initials: I
authors.lastname: Pigeot
authors.affiliation: Epidemiology and Population Genetics, Institute of Food Science, National Research Council, Avellino, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Barba
authors.affiliation: Department of Chronic Diseases, National Institute for Health Development, Tallinn, Estonia.
authors.forename: T
authors.initials: T
authors.lastname: Veidebaum
authors.affiliation: Research and Education Institute of Child Health, Strovolos, Cyprus.
authors.forename: M
authors.initials: M
authors.lastname: Tornaritis
authors.affiliation: Department of Public Health, University of Ghent, Ghent, Belgium.
authors.forename: N
authors.initials: N
authors.lastname: Michels
authors.affiliation: Department of Public Health and Community Medicine, University of Gothenburg, Gothenburg, Sweden.
authors.forename: G
authors.initials: G
authors.lastname: Eiben
authors.affiliation: 1] Leibniz Institute for Prevention Research and Epidemiology-BIPS, Bremen, Germany [2] Institute of Statistics, Faculty of Mathematics and Computer Science, Bremen University, Bremen, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Ahrens
authors.affiliation: Growth, Exercise, Nutrition and Development (GENUD) Research Group, University of Zaragoza, Zaragoza, Spain.
authors.forename: L A
authors.initials: LA
authors.lastname: Moreno
authors.affiliation: Department of Paediatrics, University of Pécs, Pécs, Hungary.
authors.forename: E
authors.initials: E
authors.lastname: Kovács
authors.affiliation: Department of Paediatrics, University of Pécs, Pécs, Hungary.
authors.forename: D
authors.initials: D
authors.lastname: Molnár
mesh_terms: D052242:Adiponectin / Q000097:blood*; D000367:Age Factors; D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005060:Europe / Q000453:epidemiology; D005215:Fasting; D005260:Female; D006306:Health Surveys; D006801:Humans; D020738:Leptin / Q000097:blood*; D008019:Life Style; D008297:Male; D011237:Predictive Value of Tests; D012016:Reference Values; D012737:Sex Factors; D044465:White People
chemical_list: D052242:Adiponectin; D015415:Biomarkers; D020738:Leptin