Abstract: ObjectiveTo study the distribution of normal WC and provide a reference for the establishment of the screening criteria of overweight and obesity in Chinese children and adolescent by utilizing the BMI criteria for children and adolescents developed by WGOC. Methods146,306 Han primary and middle school students aged 7-18 years old from 15 provinces or cities monitored by National Student Physical Health Survey in 2008 were recruited as subjects. Using BMI criteria for children and adolescents developed by The WGOC as the reference, the WC cutoff points of overweight and obesity in children and adolescents were analyzed with ROC curve. ResultsThe correlation coefficients between BMI and WC were generally beyond 0.8 for boys, and 0.7 for girls (except 7-year-old girls); For overweight category, WC cutoff point of 7-12 years boys were mainly at the 70th percentile (WC58.1.0-68.3cm), for13-18 years, 75th percentile(71.5-76.0cm), and the sensitivities and the specificities were between 0.808-0.922 and 0.824-0.912 respectively. WC cutoff point of 7-8-year girls were mainly at the 75th percentile (WC:56.3-58.1cm), and 9-18 years, the 80th percentile (WC:61.3-72.9cm)with the sensitivities and the specificities being between 0.770-0.905 and 0.811-0.983 respectively. For obesity category, WC cutoff point of 7-12 year-old boys were mainly at the 85th percentile (WC:62.4-73.8cm), 13-18 years, at the 90th percentile (WC:78.8-82.1cm) with the sensitivities and the specificities being between 0.872-0.937 and 0.868-0.943 respectively. WC cutoff point of 7-10 year-old girls were mainly at the 85th percentile (WC:59.1-65.3cm), and 11-18 years at the 90th percentile (WC:70.1-76.4cm) with the sensitivities and the specificities being between 0.789-0.936 and 0.881-0.932 respectively. ConclusionFor overweight category, the WC cutoff points were proposed at the 75th percentile for boys and the 80th for girls. For obesity category, the WC cutoff points before puberty were proposed at the 85th percentile and the 90th percentile after the puberty (boys of 13 years old, girls of 11 years old or so in China).

Key words: children and adolescents, waist circumference, ROC curve, overweight , obesity, BMI