title: Relationship of high leptin levels with an adverse lipid and insulin profile in 6-8 year-old children in Spain.
abstract: OBJECTIVE
  Leptin, an adipokine elevated in obesity, may be related to an adverse cardiovascular risk profile in childhood. However, evidence for this relationship in pre-pubertal children is scarce. We aimed to analyze the relationship between leptin levels and lipid and insulin profiles in Spanish children.
  
  
  RESULTS
  Our population-based sample included 389 males and 369 females aged 6-8 years. Lipid levels were determined by standard methods, insulin by radioimmunoassay and leptin by sandwich ELISA. Leptin levels were higher in girls (8.6 ng/ml) than boys (4.7 ng/ml) (p < 0.001). Leptin increased from ages 6 to 8 in girls, but remained steady in boys. In both sexes, leptin increased significantly (p < 0.001) across weight category from normal weight to obese. Children in the highest tertile of leptin concentration showed significantly (p < 0.01) lower levels of HDL-cholesterol (HDL-C) and apolipoprotein-AI (apo-AI) and significantly higher triglyceride (TG) levels than children in lower tertiles. However, in linear regression analysis, after adjustment for body mass index (BMI), leptin only accounted for 1.5% of the variance of HDL-C in boys, and 2.6% of the variance of apo-AI in girls. Leptin was strongly and positively correlated with insulin and HOMA. Upon regression analysis, leptin contributed to over 20% of the variability in insulin and HOMA, independent of BMI.
  
  
  CONCLUSIONS
  Leptin levels show sex differences in pre-pubertal children. In this age group, leptin levels are strongly related to insulin, and affect lipid profile -namely HDL-C, apo-AI and TG- particularly when leptin levels are high.
authors.affiliation: Lipid Laboratory, IIS-Fundación Jiménez Díaz, UAM, Madrid, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Jois
authors.affiliation: Lipid Laboratory, IIS-Fundación Jiménez Díaz, UAM, Madrid, Spain.
authors.forename: P
authors.initials: P
authors.lastname: Navarro
authors.affiliation: Servicio de Bioquímica-Investigación, Hospital Ramón y Cajal, Madrid, Spain.
authors.forename: H
authors.initials: H
authors.lastname: Ortega-Senovilla
authors.affiliation: Department of Pediatrics, IIS-Fundación Jiménez Díaz, UAM, Madrid, Spain.
authors.forename: T
authors.initials: T
authors.lastname: Gavela-Pérez
authors.affiliation: Department of Pediatrics, IIS-Fundación Jiménez Díaz, UAM, Madrid, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Soriano-Guillén
authors.affiliation: Lipid Laboratory, IIS-Fundación Jiménez Díaz, UAM, Madrid, Spain. Electronic address: cgarces@fjd.es.
authors.forename: C
authors.initials: C
authors.lastname: Garcés
mesh_terms: D000367:Age Factors; D000886:Anthropometry; D016632:Apolipoprotein A-I / Q000097:blood; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000503:physiopathology; D002648:Child; D008076:Cholesterol, HDL / Q000097:blood; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D006949:Hyperlipidemias / Q000097:blood* / Q000453:epidemiology* / Q000503:physiopathology; D007328:Insulin / Q000378:metabolism; D007333:Insulin Resistance; D020738:Leptin / Q000097:blood* / Q000378:metabolism; D016014:Linear Models; D008297:Male; D024821:Metabolic Syndrome / Q000453:epidemiology* / Q000503:physiopathology; D015999:Multivariate Analysis; D018570:Risk Assessment; D012737:Sex Factors; D013030:Spain / Q000453:epidemiology
chemical_list: D016632:Apolipoprotein A-I; D008076:Cholesterol, HDL; D007328:Insulin; D020738:Leptin
keywords: 6–8 year-old children; HDL-Cholesterol; Insulin; Leptin; TG; apo-AI