title: Abdominal obesity and low physical activity are associated with insulin resistance in overweight adolescents: a cross-sectional study.
abstract: BACKGROUND
  Previous studies have assessed the metabolic changes and lifestyles associated with overweight adolescents. However, these associations are unclear amongst overweight adolescents who have already developed insulin resistance. This study assessed the associations between insulin resistance and anthropometric, metabolic, inflammatory, food consumption, and physical activity variables amongst overweight adolescents.
  
  
  METHODS
  This cross-sectional study divided adolescents (n = 120) between 10 and 18 years old into 3 groups: an overweight group with insulin resistance (O + IR), an overweight group without insulin resistance (O-IR), and a normal-weight control group (NW). Adolescents were matched across groups based on age, sex, pubertal maturation, and socioeconomic strata. Anthropometric, biochemical, physical activity, and food consumption variables were assessed. Insulin resistance was assessed using homeostatic model assessment (HOMA Calculator Version 2.2.2 from ©Diabetes Trials Unit, University of Oxford), and overweight status was assessed using body mass index according to World Health Organization (2007) references. A chi-square test was used to compare categorical variables. ANOVAs or Kruskal-Wallis tests were used for continuous variables. Multiple linear regression models were used to calculate the probability of the occurrence of insulin resistance based on the independent variables.
  
  
  RESULTS
  The risk of insulin resistance amongst overweight adolescents increases significantly when they reach a waist circumference > p95 (OR = 1.9, CIs = 1.3-2.7, p = 0.013) and watch 3 or more hours/day of television (OR = 1.7, CIs = 0.98-2.8, p = 0.033). Overweight status and insulin resistance were associated with higher levels of inflammation (hsCRP ≥1 mg/L) and cardiovascular risk according to arterial indices. With each cm increase in waist circumference, the HOMA index increased by 0.082; with each metabolic equivalent (MET) unit increase in physical activity, the HOMA index decreased by 0.026.
  
  
  CONCLUSIONS
  Sedentary behaviour and a waist circumference > p90 amongst overweight adolescents were associated with insulin resistance, lipid profile alterations, and higher inflammatory states. A screening that includes body mass index, in waist circumference, and physical activity evaluations of adolescents might enable the early detection of these alterations.
authors.affiliation: Research Group in Food and Human Nutrition, Universidad de Antioquia (UdeA), Calle 70 No, 52-21, Medellín, Colombia. claudia.velasquez@udea.edu.co.
authors.forename: Claudia-María
authors.initials: CM
authors.lastname: Velásquez-Rodríguez
authors.forename: Marcela
authors.initials: M
authors.lastname: Velásquez-Villa
authors.forename: Leidy
authors.initials: L
authors.lastname: Gómez-Ocampo
authors.forename: Juliana
authors.initials: J
authors.lastname: Bermúdez-Cardona
mesh_terms: D000293:Adolescent; D002097:C-Reactive Protein / Q000032:analysis; D016022:Case-Control Studies; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology*; D016014:Linear Models; D008055:Lipids / Q000097:blood; D008297:Male; D056128:Obesity, Abdominal / Q000503:physiopathology*; D050177:Overweight / Q000097:blood / Q000503:physiopathology*; D057185:Sedentary Behavior
chemical_list: D008055:Lipids; D002097:C-Reactive Protein