title: Severe obesity and cardiometabolic risk in children: comparison from two international classification systems.
abstract: OBJECTIVE
  There is no agreed-upon definition for severe obesity (Sev-OB) in children. We compared estimates of Sev-OB as defined by different cut-points of body mass index (BMI) from the Centers for Disease Control and Prevention (CDC) or the World Health Organization (WHO) curves and the ability of each set of cut-points to screen for the presence of cardiometabolic risk factors.
  
  
  METHODS
  Cross-sectional, multicenter study involving 3,340 overweight/obese young subjects. Sev-OB was defined as BMI ≥ 99(th) percentile or ≥ 1.2 times the 95(th) percentile of the CDC or the WHO curves. High blood pressure, hypertriglyceridemia, low High Density Lipoprotein -cholesterol and impaired fasting glucose were considered as cardiometabolic risk factors.
  
  
  RESULTS
  The estimated prevalence of Sev-OB varied widely between the two reference systems. Either using the cut-point ≥ 99(th) percentile or ≥ 1.2 times the 95(th) percentile, less children were defined as Sev-OB by CDC than WHO (46.8 vs. 89.5%, and 63.3 vs. 80.4%, respectively p<0.001). The CDC 99(th) percentile had lower sensitivity (58.5 vs 94.2), higher specificity (57.6 vs 12.3) and higher positive predictive value (34.4 vs 28.9) than WHO in identifying obese children with ≥ 2 cardiometabolic risk factors. These differences were mitigated using the 1.2 times the 95(th) percentile (sensitivity 73.9 vs. 88.1; specificity 40.7 vs. 22.5; positive predictive value 32.1 vs. 30.1). Substantial agreement between growth curves was found using the 1.2 times the 95(th) percentile, in particular in children ≤ 10 years.
  
  
  CONCLUSIONS
  Estimates of Sev-OB and cardiometabolic risk as defined by different cut-points of BMI are influenced from the reference systems used. The 1.2 times the 95(th) percentile of BMI of either CDC or WHO standard has a discriminatory advantage over the 99(th) percentile for identifying severely obese children at increased cardiometabolic risk, particularly under 10 years of age.
authors.affiliation: Dipartimento di Scienze Motorie e del Benessere, Università degli Studi di Napoli Parthenope, Napoli, Italy.
authors.forename: Giuliana
authors.initials: G
authors.lastname: Valerio
authors.affiliation: Unità Operativa Complessa di Diabetologia, Nutrizione Clinica e Obesità in Età Pediatrica, Università di Verona, Verona, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Maffeis
authors.affiliation: Dipartimento di Scienze Mediche e Chirurgiche, Programma di Endocrinologia Pediatrica, Unità Operativa di Pediatria, Università di Bologna, Policlinico S. Orsola-Malpighi, Bologna, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Balsamo
authors.affiliation: Dipartimento della Donna, del Bambino e di Chirurgia Generale e Specialistica, Seconda Università di Napoli, Napoli, Italy.
authors.forename: Emanuele Miraglia
authors.initials: EM
authors.lastname: Del Giudice
authors.affiliation: Unità Operativa Complessa di Endocrinologia e Diabetologia, Ospedale Pediatrico Bambino Gesù, Roma, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Brufani
authors.affiliation: Divisione di Auxologia, Istituto Auxologico Italiano, Piancavallo, Verbania, Italy.
authors.forename: Graziano
authors.initials: G
authors.lastname: Grugni
authors.affiliation: Unità Operativa Complessa di Auxologia ed Endocrinologia - Dipartimento di Pediatria Sistematica e Specialistica - Azienda Ospedaliera di Rilevanza Nazionale Santobono-Pausilipon-Annunziata, Napoli, Italy.
authors.forename: Maria Rosaria
authors.initials: MR
authors.lastname: Licenziati
authors.affiliation: Dipartimento di Pediatria, Istituto Scientifico San Raffaele, Milano and Azienda Sanitaria Locale 2, Melegnano, Milano, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Brambilla
authors.affiliation: Direzione Scientifica, Area di Ricerca Malattie Multifattoriali, Obesità e Diabete, Ospedale Pediatrico Bambino Gesù, Roma, Italy.
authors.forename: Melania
authors.initials: M
authors.lastname: Manco
mesh_terms: D000293:Adolescent; D015992:Body Mass Index; D002487:Centers for Disease Control and Prevention, U.S. / Q000592:standards; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D005260:Female; D006801:Humans; D038622:Internationality; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D009767:Obesity, Morbid / Q000097:blood / Q000453:epidemiology* / Q000378:metabolism*; D012307:Risk Factors; D014481:United States; D014944:World Health Organization