title: Comparing three body mass index classification systems to assess overweight and obesity in children and adolescents.
abstract: OBJECTIVE
  To compare the International Obesity Task Force (IOTF) 2005, Centers for Disease Control and Prevention (CDC) 2000, and World Health Organization (WHO) 2007 body mass index (BMI) classification systems in terms of prevalence estimation and association with demographic factors.
  
  
  METHODS
  The 18 265 children and adolescents ages 5 to 18 years (mean = 11.2 years, standard deviation = 3.9 years) in the nationally representative Colombian National Nutrition Survey of 2005 were classified as overweight or obese according to IOTF, CDC, and WHO criteria. Prevalence estimates were compared according to each system and associations with age, sex, socioeconomic status, and population density were tested.
  
  
  RESULTS
  Prevalence estimates of combined overweight and obesity differed by system (males: IOTF = 8.5%, CDC = 10.8%, WHO = 14.1%; females: IOTF = 14.6%, CDC = 13.8%, WHO = 17.1%; P < 0.001). The association between combined overweight and obesity and age and sex varied by system. The odds of having overweight and obesity in children (5 to 10 years) compared with adolescents (11 to 18 years) were: IOTF, odds ratio (OR) = 0.87 and 95% confidence interval (CI) = 0.77-0.98; CDC, OR = 1.27 and CI = 1.14-1.42; WHO, OR = 1.21 and CI = 1.08-1.35. The values for females compared with males were: IOTF, OR = 1.84 and CI = 1.6-2.10; CDC, OR = 1.33 and CI = 1.17-1.51; WHO, OR = 1.25 and CI = 1.12-1.41.
  
  
  CONCLUSIONS
  There is a lack of consistency among the three main international systems in assessing overweight and obesity in children and adolescents. Appreciably different estimates of prevalence and associations with age and sex are obtained depending on which system is used. Future studies should assess how well each system reflects valid measures of body composition.
authors.affiliation: Graduate Division of Biological, Biomedical Sciences, Emory University, Atlanta, GA 30322, United States of America. igonza2@emory.edu
authors.forename: Ines
authors.initials: I
authors.lastname: Gonzalez-Casanova
authors.forename: Olga L
authors.initials: OL
authors.lastname: Sarmiento
authors.forename: Julie A
authors.initials: JA
authors.lastname: Gazmararian
authors.forename: Solveig A
authors.initials: SA
authors.lastname: Cunningham
authors.forename: Reynaldo
authors.initials: R
authors.lastname: Martorell
authors.forename: Michael
authors.initials: M
authors.lastname: Pratt
authors.forename: Aryeh D
authors.initials: AD
authors.lastname: Stein
mesh_terms: D000293:Adolescent; D015992:Body Mass Index; D002487:Centers for Disease Control and Prevention, U.S.; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D009765:Obesity / Q000145:classification* / Q000453:epidemiology*; D050177:Overweight / Q000145:classification* / Q000453:epidemiology*; D015995:Prevalence; D014481:United States; D014944:World Health Organization