The association between BMI and body weight perception among children and adolescents in Jilin City, China

Objectives We evaluated the association between BMI and body weight perception in a sample of children and adolescents. Methods A cross-sectional school-based study was conducted among 7-18 year-olds (N = 9727) from 4 districts in Jilin City, China. We calculated BMI from measured weight and height and assessed body weight perception using a single questionnaire item. We analyzed these data using SPSS version 20.0. Results Approximately 19.8% of these youth perceived themselves as underweight, 57.8% as normal weight, and 22.4% as overweight. In reality, 4.9% were underweight, 64.3% were normal weight, and 30.8% were overweight. Furthermore, approximately 66.4% of these Chinese youth correctly perceived their body image, 28.2% underestimated their true body image, and 5.4% overestimated their weight status. Girls were more likely than boys to overestimate their weight (chi(2) = 135.4, p < 0.05). Adolescents 13-18 years old were more likely than children 7-12 years old to overestimate their weight (chi(2) = 248.4, p < 0.05). Senior high school students were the most likely to overestimate their weight (chi(2) = 297.6, p < 0.05). Kappa tests revealed significant differences in consistency analysis of BMI and body weight perception (Kappa = 0.352, p < 0.05). Kappa < 0.4, the consistency of BMI and body weight perception was poor. Conclusions A mismatch existed between BMI and body weight perception among these children and adolescents. Thus, schools and parents should take steps to help them improve weight management and overall health awareness.