title: Associations among osteocalcin, leptin and metabolic health in children ages 9-13 years in the United States.
abstract: BACKGROUND
  This study aimed to investigate the relationships among osteocalcin, leptin and metabolic health outcomes in children ages 9-13 years.
  
  
  METHODS
  This was a cross-sectional analysis of baseline data from 161 boys and 157 girls (ages 9-13 years) who previously participated in a double-blinded randomized placebo controlled trial of vitamin D supplementation. Relationships among fasting serum total osteocalcin (tOC), undercarboxylated osteocalcin (ucOC), leptin, and metabolic health outcomes were analyzed.
  
  
  RESULTS
  Approximately 52% of study participants were obese based on percent body fat cutoffs (>25% for boys and >32% for girls) and about 5% had fasting serum glucose within the prediabetic range (i.e. 100 to 125 mg/dL). Serum tOC was not correlated with leptin, glucose, insulin, HOMA-IR, or HOMA-β after adjusting for percent body fat. However, serum ucOC negatively correlated with leptin (partial r = -0.16;p= 0.04) and glucose (partial r = -0.16;p= 0.04) after adjustment for percent body fat. Leptin was a positive predictor of insulin, glucose, HOMA-IR, and HOMA-β after adjusting for age, sex and percent body fat (allp< 0.001).
  
  
  CONCLUSIONS
  These data depict an inverse relationship between leptin and various metabolic health outcomes in children. However, the notion that tOC or ucOC link fat with energy metabolism in healthy children was not supported.
  
  
  BACKGROUND
  NCT00931580.
authors.affiliation: Department of Nutrition, School of Public Health, University of São Paulo, Avenida Doutor Arnaldo 715, São Paulo, CEP 01246-904 Brazil.
authors.forename: Kelly Virecoulon
authors.initials: KV
authors.lastname: Giudici
authors.affiliation: Department of Foods and Nutrition, University of Georgia, 305 Sanford Dr, Athens, GA 30602 USA.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Kindler
authors.affiliation: Department of Nutrition Science, Purdue University, 700 W. State Street, West Lafayette, IN 47907 USA.
authors.forename: Berdine R
authors.initials: BR
authors.lastname: Martin
authors.affiliation: Department of Foods and Nutrition, University of Georgia, 305 Sanford Dr, Athens, GA 30602 USA.
authors.forename: Emma M
authors.initials: EM
authors.lastname: Laing
authors.affiliation: Department of Statistics, Purdue University, 150 N. University Street, West Lafayette, IN 47907 USA.
authors.forename: George P
authors.initials: GP
authors.lastname: McCabe
authors.affiliation: Department of Nutrition Science, Purdue University, 700 W. State Street, West Lafayette, IN 47907 USA.
authors.forename: Linda D
authors.initials: LD
authors.lastname: McCabe
authors.affiliation: Department of Foods and Nutrition, University of Georgia, 305 Sanford Dr, Athens, GA 30602 USA.
authors.forename: Dorothy B
authors.initials: DB
authors.lastname: Hausman
authors.affiliation: Department of Nutrition, School of Public Health, University of São Paulo, Avenida Doutor Arnaldo 715, São Paulo, CEP 01246-904 Brazil.
authors.forename: Lígia Araújo
authors.initials: LA
authors.lastname: Martini
authors.affiliation: Department of Foods and Nutrition, University of Georgia, 305 Sanford Dr, Athens, GA 30602 USA.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Lewis
authors.affiliation: Department of Nutrition Science, Purdue University, 700 W. State Street, West Lafayette, IN 47907 USA.
authors.forename: Connie M
authors.initials: CM
authors.lastname: Weaver
authors.affiliation: Department of Medicine, Indiana University School of Medicine, 545 Barnhill Dr, Indianapolis, IN 46202 USA.
authors.forename: Munro
authors.initials: M
authors.lastname: Peacock
authors.affiliation: Department of Nutrition Science, Purdue University, 700 W. State Street, West Lafayette, IN 47907 USA.
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Hill Gallant
keywords: Children; Glucose; Insulin; Leptin; Obesity; Osteocalcin