[Study on physique index set for Chinese children and adolescents]

To provide data as age-gender dependent mean, standard deviation and percentile on height, weight, waist circumference (WC), hip circumference (HC), body mass index (BMI), waist hip ratio (WHR), waist to height ratio (WHtR) among 7-16 year-olds Chinese children and adolescents, towards setting up diagnostic criteria on metabolic syndrome for them.

A representative sample involving 22,197 children and adolescence aged 7 to 16 years were randomly surveyed and they were from 6 representative geographical areas, including Beijing, Tianjin, Hangzhou, Shanghai, Chongqing and Nanning. A total of 21 858 had available data, with male/female ratio as: 11,460/10,398. Using the standard methods, we measured height, weight, WC, HC, BMI, WHtR and other data in all age groups. Physique indexes among different geographic regions (North, Mid-west and East) were compared.

(1) Both male and female showed an increasing trend of height, weight, waist circumference, hip circumference and BMI along with the increase of age. WHR of girls decreased gradually from 0.84 to 0.76 went from 7 to 16 years old while WHR of boys changed from 0.87 to 0.81 accordingly. (2) WHtR was rarely affected by age. It fluctuated between 0.42-0.43 in all girls and 0.44-0.45 in boys less than 11 years. WHtR of boys older than 12 years showed a slight decline from 0.45 to 0.42 of WHtR. (3) The average height, weight, BMI of children and adolescents from the northern regions (Beijing, Tianjin) were significantly higher than that of the mid-western (Chongqing, Nanning) and the eastern regions (Shanghai, Hangzhou) (P<0.001), while those from the mid-western region were slightly higher than that of the eastern region (P<0.05) in each of the age group.

Reference values and percentile curves for WC and WHtR of Chinese children and adolescents were provided. For the assessment of central obesity. WHtR had the advantages of relative stability and small degree of variation and rarely affected by age and gender, when compared with WC, and could be used as an simple index to reflect the central obesity of children and adolescents.