An Objective Measure to Evaluate Actual Body Shape among Children and Adolescents in China

Objective The purpose of this study was to explore an objective measure to assess actual body shape of children and adolescents in China. Methods Based on the Chinese National Survey on Student's Constitution and Health (CNSSCH) in 2005, 210 927 children and adolescents' (7-18 years) body height, body weight, chest circumference, sitting height, chest circumference-height ratio, chest circumference-sitting height ratio, chest circumference-low limb ratio, and sitting height-low limb ratio measurements were used to develop an objective measure by using transformation variables and explored factor analysis (EFA). Discrimination power of the objective measure was evaluated based on BMI reference and Receiver Operating Characteristic curves (ROC). Results The objective measure included four dimensions scores: transverse dimension (TD) indicating weight and chest circumference; length dimension (LD) indicating height and sitting height; transverse-length ratio dimension (TLD) indicating chest circumference-height ratio, chest circumference-sitting height and chest circumference-low limb ratio; proportion dimension (PD) indicating sitting height-low limb ratio. The whole dimension (WD) indicating the whole body shape was showed by the average of four dimensions scores. Four dimensions and WD scores were approximately 80 in children and adolescents with normal weight, and higher than those of overweight, obesity, and underweight (all P-values <0.001). Areas under ROC of overweight and obesity compared with normal weight ranged from 0.88 to 1.00 for scores of TD, TLD, and WD. Conclusion The objective measure which included four dimensions was explored, and TD, TLD, and WD had significant discrimination power.