¹Department of Human Nutrition, University of Illinois, Chicago, Illinois, USA

²Department of Biostatistics, University of North Carolina, Chapel Hill, North Carolina, USA

Correspondence to: Y Wang, Department of Human Nutrition, M/C 517, University of Illinois at Chicago, 1919 W Taylor St, Chicago, IL 60612, USA. E-mail: youfwang@uic.edu

^aGuarantor: Y Wang.

^bContributors: YW is the principle investigator; JW has participated in data analysis and improvement of the manuscript.

^†An earlier version of the manuscript was presented at the China Workshop on Obesity, 24-26 April 2000, Beijing, China, and in the 128th American Public Health Association Annual Meeting, 12-16 November, 2000, Boston, MA, USA.

Objective: To compare different references assessing child and adolescent overweight and obesity in different populations.

Design: Comparison cross-sectional study.

Setting: The United States, Russia, China.

Subjects: A total of 6108 American, 6883 Russian and 3014 Chinese children aged 6-18 y.

Investigation: 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) reference¾BMI 85th percentiles for overweight in adolescents (10-19 y) and weight-for-height Z-scores for obesity in children under 10; (3) a USA reference¾BMI 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.

Sponsorship: University of Illinois and University of North Carolina.

European Journal of Clinical Nutrition (2002) 56, 973-982. doi:10.1038/sj.ejcn.1601415

BMI; obesity; overweight; child; adolescent; reference