title: A comparison of international references for the assessment of child and adolescent overweight and obesity in different populations.
abstract: OBJECTIVE
  To compare different references assessing child and adolescent overweight and obesity in different populations.
  
  
  METHODS
  Comparison cross-sectional study.
  
  
  METHODS
  The United States, Russia, China.
  
  
  METHODS
  A total of 6108 American, 6883 Russian and 3014 Chinese children aged 6-18 y.
  
  
  METHODS
  Using nationwide survey data from the USA (NHANES III, 1988-1994), Russia (1992), and China (1991), we compared three references: (1) the International Obesity Task Force (IOTF) reference, sex-age-specific body mass index (BMI) cut-offs that correspond to BMIs of 25 for overweight and 30 for obesity at age 18; (2) the World Health Organization (WHO) reference--BMI 85th percentiles for overweight in adolescents (10-19 y) and weight-for-height Z-scores for obesity in children under 10; (3) a USA reference--BMI 85th and 95th percentiles to classify overweight and obesity, respectively.
  
  
  RESULTS
  Using the IOTF reference and 85th BMI percentiles, overweight prevalence was 6.4 and 6.5% in China, 15.7 and 15.0% in Russia, and 25.5 and 24.4% in the USA, respectively. Notable differences existed for several ages. Kappa (=0.84-0.98) indicated an excellent agreement between the two references in general, although they varied by sex-age groupings and countries. Overweight prevalence was twice as high in children (6-9 y) than in adolescents (10-18 y) in China and Russia, but was similar in the USA. Estimates of obesity prevalence using these three references varied substantially.
  
  
  CONCLUSIONS
  The references examined produce similar estimates of overall overweight prevalence but different estimates for obesity. One should be cautious when comparing results based on different references.
  
  
  BACKGROUND
  University of Illinois and University of North Carolina.
authors.affiliation: Department of Human Nutrition, University of Illinois, Chicago 60612, USA. youfwang@uic.edu
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.forename: J Q
authors.initials: JQ
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D000367:Age Factors; D015992:Body Mass Index; D002648:Child; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D009749:Nutrition Surveys; D009765:Obesity / Q000175:diagnosis / Q000453:epidemiology*; D015995:Prevalence; D012015:Reference Standards; D012016:Reference Values; D012426:Russia / Q000453:epidemiology; D012737:Sex Factors; D014481:United States / Q000453:epidemiology