title: Association of leptin and insulin with childhood obesity and retinal vessel diameters.
abstract: OBJECTIVE
  Childhood obesity is associated with an impaired retinal microcirculation. The aim of the study was to investigate the association between specific obesity-related biomarkers, physical fitness and retinal vessel diameters in school children.
  
  
  METHODS
  We studied 381 children aged 10-11 years (body mass index (BMI): 19.3±3.7 kg m(-2)) in a school-based setting.
  
  
  METHODS
  Anthropometric measurements and blood sampling were conducted using standard protocols for children. The serum biomarkers leptin, adiponectin, insulin as well as interleukin-6 (IL-6) were analyzed. Physical fitness was determined by a six-item-test battery and physical activity by use of a questionnaire. Central retinal arteriolar equivalent (CRAE), central retinal venular equivalent (CRVE) and the arteriolar-to-venular diameter ratio (AVR) were assessed with a non-mydriatic vessel analyzer (SVA-T) using a computer-based program.
  
  
  RESULTS
  Compared with normal weight children (n=254), obese children (n=39) showed higher leptin (P<0.001), higher insulin (P<0.001), higher IL-6 (P<0.001) and lower adiponectin levels (P=0.013). Obese children demonstrated wider CRVE (P=0.041) and lower AVR (P<0.001). Higher leptin levels were associated with wider CRVE (P=0.032) and lower AVR (P=0.010), that was BMI dependent. Insulin levels were associated with arteriolar (P=0.045) and venular dilatation (P=0.034) after adjustment for BMI. No significant associations between adiponectin levels, IL-6 levels, physical fitness or physical activity and retinal vessel diameter were observed. Lower leptin levels were independently correlated with higher physical fitness (r=-0.33; P<0.001).
  
  
  CONCLUSIONS
  Leptin and insulin levels are associated with changes of the retinal microcirculation. Especially insulin seems to be a good target marker for the cardiometabolic risk assessment in children since elevated insulin levels are independently associated with microvascular end-organ alterations at an early stage. Lifestyle intervention studies are warranted to examine whether improvement of physical fitness or weight reduction can affect cardiometabolic risk markers and reverse alterations of the retinal microcirculation.
authors.affiliation: Department of Prevention, Rehabilitation and Sports Medicine, Technische Universität München, Klinikum rechts der Isar, Munich, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Siegrist
authors.affiliation: 1] Department of Prevention, Rehabilitation and Sports Medicine, Technische Universität München, Klinikum rechts der Isar, Munich, Germany [2] Division of Sports Medicine, Institute of Exercise and Health Sciences, University of Basel, Basel, Switzerland.
authors.forename: H
authors.initials: H
authors.lastname: Hanssen
authors.affiliation: Department of Prevention, Rehabilitation and Sports Medicine, Technische Universität München, Klinikum rechts der Isar, Munich, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Neidig
authors.affiliation: Department of Prevention, Rehabilitation and Sports Medicine, Technische Universität München, Klinikum rechts der Isar, Munich, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Fuchs
authors.affiliation: Department of Prevention, Rehabilitation and Sports Medicine, Technische Universität München, Klinikum rechts der Isar, Munich, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Lechner
authors.affiliation: Department of Prevention, Rehabilitation and Sports Medicine, Technische Universität München, Klinikum rechts der Isar, Munich, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Stetten
authors.affiliation: Department of Prevention, Rehabilitation and Sports Medicine, Technische Universität München, Klinikum rechts der Isar, Munich, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Blume
authors.affiliation: Department of Prevention, Rehabilitation and Sports Medicine, Technische Universität München, Klinikum rechts der Isar, Munich, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Lammel
authors.affiliation: Institute of Medical Statistics and Epidemiology, Technische Universität München, Klinikum rechts der Isar, Munich, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Haller
authors.affiliation: Department of Clinical Chemistry, University of Munich, Grosshadern Campus, Munich, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Vogeser
authors.affiliation: Department of Internal Medicine II, University of Munich, Grosshadern Campus, Munich, Germany.
authors.forename: K G
authors.initials: KG
authors.lastname: Parhofer
authors.affiliation: 1] Department of Prevention, Rehabilitation and Sports Medicine, Technische Universität München, Klinikum rechts der Isar, Munich, Germany [2] DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Munich, Germany [3] Else Kröner-Fresenius-Zentrum am Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Halle
mesh_terms: D052242:Adiponectin / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D001794:Blood Pressure; D015992:Body Mass Index; D002648:Child; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood*; D015850:Interleukin-6 / Q000097:blood*; D020738:Leptin / Q000097:blood*; D008297:Male; D008833:Microcirculation; D063766:Pediatric Obesity / Q000097:blood* / Q000150:complications / Q000473:pathology; D015995:Prevalence; D012171:Retinal Vessels / Q000473:pathology*; D018570:Risk Assessment; D012307:Risk Factors; D040242:Risk Reduction Behavior; D011795:Surveys and Questionnaires
chemical_list: D052242:Adiponectin; D015415:Biomarkers; D007328:Insulin; D015850:Interleukin-6; D020738:Leptin