Secular changes on the distribution of body mass index among Chinese children and adolescents, 1985-2010.

Objective: To analyze the change in Body Mass Index (BMI) distribution among Chinese children and adolescents for the development of more effective intervention for childhood obesity.

Methods: Data on the national students' constitution and health survey between 1985 and 2010 was used for this study. Subjects were students aged 7-18 randomly selected from 30 provinces in China. BMI for-age curves were developed by LMS method, and the trend of BMI distribution was determined by comparing the upper BMI percentiles and analyzing the skew shift of distribution between 1985 and 2010.

Results: An overall positive swift trend of BMI between 1985 and 2010 was observed among the Chinese school-age children and adolescents. The average median of the BMI increased from 16.8 and 17.0 kg/m2 to 18.2 and 17.9 kg/m2 in 25 years, with increments 0.56 and 0.36 kg/m2 per decade for males and females, respectively. The more obvious increments were found at the high BMI. The total increments of BMI in this period were 4.03 and 2.20 kg/m2 at the 85th, 6.14 and 3.57 kg/m2 at the 95th, and 6.99 and 4.27 kg/m2 at the 97th percentiles, for males and females, respectively.

Conclusion: Obvious increments were observed at high BMI of the Chinese children and adolescents. More effective interventions should be taken for control and prevention of obesity and its health consequence for these subgroups. It is necessary to establish a risk-complex system consisting of the identification of BMI scope, the screen of the disease risk factors and the assessment of excessive adiposity.