Body mass index for children aged 6-18 years in Beijing, China

Background: Obesity constitutes one of the most important worldwide public health concerns. Aim: To develop BMI percentile curves by age, sex and urban-rural regions for Beijing children and compare the results with Chinese national data and international references. Subjects and methods: Boys (4078) and girls (4077), aged 6-18 years, were recruited from 1 September to 30 November 2005 in Beijing, China. BMI percentile curves were constructed using the LMS method. Results: BMI curves differed between boys and girls. BMI curves for urban children were higher than rural children at the upper percentile. Beijing BMI curves were higher than the Chinese national level. Beijing boys had a higher BMI in medium (6.5-14 years) and upper percentiles and a lower BMI in lower percentiles than WHO and developed references, whereas Beijing girls were lower in medium and lower percentiles, but higher compared to a WHO reference before age 15.5 years in upper percentiles. Conclusions: Beijing children are fatter than the Chinese national level. Beijing urban children are fatter than rural Beijing children. The polarization of BMI values for Beijing boys suggests these children face a dual-burden of nutrition. Effective policies and interventions to control obesity and underweight in Chinese children are necessary.