title: Comparison between CDC and WHO BMI z-score and their relation with metabolic risk markers in Northern Portuguese obese adolescents.
abstract: BACKGROUND
  Growth-curves are an important tool for evaluating the anthropometric development in pediatrics. The different growth-curves available are based in different populations, what leads to different cut-offs. Pediatric obesity tracks into adulthood and is associated with increased cardiovascular risk. The accurate assessment of a child nutritional status using growth-curves can indicate individuals that are either obese or in risk of becoming obese, allowing an early intervention. Moreover, the association between the data obtained from growth-curves with specific metabolic risk factors further highlights the importance of these charts. This study aimed to evaluate the associations between body mass index z-score (BMIzsc), determined using the growth-curves from the Centre for Disease Control and Prevention (CDC) and from the World Health Organization (WHO), with cardiovascular risk factors, represented here by metabolic syndrome (MS) and insulin resistance (IR) related parameters. The study involved 246 obese adolescents (10-18 years, 122 females). MS was defined according to the International Diabetes Federation. IR was considered for HOMA-IR greater than 2.5.
  
  
  RESULTS
  No difference between both BMIzsc in identifying MS was noticeable by a ROC analysis. For both indexes the area-under-the-curve increased for older groups, particularly for males. CDC-BMIzsc was the best predictor of MS by logistic regression when all population was considered, however MS was better predicted by WHO-BMIzsc for females and by CDC-BMIzsc for males. Younger girls and older boys were in increased risk for MS. Similar results were obtained for IR.
  
  
  CONCLUSIONS
  A significant difference between the two BMIzsc regarding their association with MS and IR was not clear, being these associations weaker in younger individuals.
authors.affiliation: Biological Science Department, Faculty of Pharmacy, University of Porto, Porto, Portugal ; Instituto de Biologia Molecular e Celular (Institute for Molecular and Cell Biology), Universidade do Porto, Porto, Portugal ; Instituto de Investigação e Inovação em Saúde (Institute for Research and Innovation in Health), Universidade do Porto, Porto, Portugal.
authors.forename: Henrique
authors.initials: H
authors.lastname: Nascimento
authors.affiliation: Biological Science Department, Faculty of Pharmacy, University of Porto, Porto, Portugal ; Instituto de Biologia Molecular e Celular (Institute for Molecular and Cell Biology), Universidade do Porto, Porto, Portugal ; Instituto de Investigação e Inovação em Saúde (Institute for Research and Innovation in Health), Universidade do Porto, Porto, Portugal.
authors.forename: Cristina
authors.initials: C
authors.lastname: Catarino
authors.affiliation: Population Study Department, Biomedical Sciences Institute Abel Salazar (ICBAS), University of Porto, Porto, Portugal.
authors.forename: Denisa
authors.initials: D
authors.lastname: Mendonça
authors.affiliation: Population Study Department, Biomedical Sciences Institute Abel Salazar (ICBAS), University of Porto, Porto, Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Oliveira
authors.affiliation: Instituto de Biologia Molecular e Celular (Institute for Molecular and Cell Biology), Universidade do Porto, Porto, Portugal ; Instituto de Investigação e Inovação em Saúde (Institute for Research and Innovation in Health), Universidade do Porto, Porto, Portugal ; Research Centre in Physical Activity, Health and Leisure (CIAFEL), Faculty of Sports, University of Porto, Porto, Portugal.
authors.forename: Ana Inês
authors.initials: AI
authors.lastname: Alves
authors.affiliation: Research Centre in Physical Activity, Health and Leisure (CIAFEL), Faculty of Sports, University of Porto, Porto, Portugal.
authors.forename: Ana Filipa
authors.initials: AF
authors.lastname: Medeiros
authors.affiliation: Health Science Research Centre, University of Beira Interior, Covilhã, Portugal.
authors.forename: Petronila Rocha
authors.initials: PR
authors.lastname: Pereira
authors.affiliation: Children and Adolescent Centre, CUF Hospital; Center for Health Technology and Services Research (CINTESIS), Faculty of Medicine, University of Porto, Porto, Portugal.
authors.forename: Carla
authors.initials: C
authors.lastname: Rêgo
authors.affiliation: Childhood and Adolescence Department/Paediatric Service of Porto Hospital Centre, Porto, Portugal.
authors.forename: Helena Ferreira
authors.initials: HF
authors.lastname: Mansilha
authors.affiliation: Research Centre in Physical Activity, Health and Leisure (CIAFEL), Faculty of Sports, University of Porto, Porto, Portugal ; University Institute of Maia (ISMAI), S. Pedro Avioso, Portugal.
authors.forename: Luísa
authors.initials: L
authors.lastname: Aires
authors.affiliation: Research Centre in Physical Activity, Health and Leisure (CIAFEL), Faculty of Sports, University of Porto, Porto, Portugal.
authors.forename: Jorge
authors.initials: J
authors.lastname: Mota
authors.affiliation: Instituto de Biologia Molecular e Celular (Institute for Molecular and Cell Biology), Universidade do Porto, Porto, Portugal ; Instituto de Investigação e Inovação em Saúde (Institute for Research and Innovation in Health), Universidade do Porto, Porto, Portugal ; Biomedical Sciences Institute Abel Salazar (ICBAS), University of Porto, Porto, Portugal.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Quintanilha
authors.affiliation: Biological Science Department, Faculty of Pharmacy, University of Porto, Porto, Portugal ; Instituto de Biologia Molecular e Celular (Institute for Molecular and Cell Biology), Universidade do Porto, Porto, Portugal ; Instituto de Investigação e Inovação em Saúde (Institute for Research and Innovation in Health), Universidade do Porto, Porto, Portugal.
authors.forename: Alice
authors.initials: A
authors.lastname: Santos-Silva
authors.affiliation: Biological Science Department, Faculty of Pharmacy, University of Porto, Porto, Portugal ; Instituto de Biologia Molecular e Celular (Institute for Molecular and Cell Biology), Universidade do Porto, Porto, Portugal ; Instituto de Investigação e Inovação em Saúde (Institute for Research and Innovation in Health), Universidade do Porto, Porto, Portugal.
authors.forename: Luís
authors.initials: L
authors.lastname: Belo
keywords: BMI z-score; CDC; Insulin resistance; Metabolic syndrome; WHO