Distribution Profile Of Waist Circumference, Hip Circumference And Waist-to-hip Ratio Among Changsha Adolescents And Investigation Of Cutoff Values For Waist Circumference

Objective:To analyze the distribution of waist circumference(WC), hip circumference(HC)and waist-to-hip ratio(WHR)among children and adolescents aged from 11 to 18 years old in Changsha urban area,and to expore the genders differences of the variables and cutoff values of waist circumference.Methods:Four middle schools in Changsha urban area were randomly selected and 2490 students aged from 11 to 18 years old who were enrolled in the Physical Fitness and Health Surveillance of Chinese School Students in 2005 were recruited to measure WC and HC.We calculated the percentiles,means,standard deviations of WC,HC and WHR of these students.The gender differences of these variables and the distribution of age were analyzed.WC distribution of children and adolescent groups in Changsha urban area were compared with that in different regions and countries.Kappa test was used to estimate the consistency of different cutoff for WC with P₈₅of body mass index(BMI) in defining overweight.Results:(1)The waist circumference was increasing with age in all samples and it is significantly higher in boys than in girls (P=0.000～0.004);(2)The hip circumference was increasing with age in boys and it is significantly higher in girls than in boys except in group of 18 years old(P=0.000～0.005);(3)The waist-to-hip ratio of boys were higher than that of girls(P=0.000);(4)Compared with other regions and countries,WC of Changsha boys was significantly lower than that of America and was significantly higher than that of Beijing and Anhui but much close to that of Turkish from 14 to 16 years old.For girls,WC was significantly lower in Changsha than in America before 14 years old,but was exceeded by that of Beijing afer 14 years.The WC of Changsha was much close to that of Turkish from 15 to 16 years old;(5)It is suggested that the optimal cutoff values of WC are P₇₅and P₈₅,respectively in Changsha boys and girls aged from 12 to 17 years old.Conclusions:(1)There are significant gender and age differences of WC,HC and WHR in children and adolescents of Changsha;(2)There are significant differences of WC for children and adolescents in different regions and countries;(3)We suggest that the age-specific optimal cutoff values of WC for Changsha children and adolescents are the 75th percentiles and the 85th percentiles for boys and girls aged from 12 to 17 years old respectively.