Changes in BMI and waist circumference among primary and secondary school students from 2005 to 2010 in Anhui, China

Aim: To examine the change in Body Mass Index (BMI) and waist circumference (WC) among primary and secondary school students aged 7-18 in Anhui Province between 2005-2010. Subjects and methods: A total of 15 812 primary and secondary school students aged 7-18 were included in two national surveys on students' constitution and health in 2005 and 2010 in Anhui Province. Measurements of height, weight and WC were taken by trained investigators. BMI was calculated for each subject. Results: The mean BMI and WC were significantly increased from 2005 to 2010. For boys, mean increases were 0.85 kg/m(2) and 2.01 cm or 0.08 and 0.34 SD score units, while for girls those were 0.39 kg/m(2) and 2.10 cm or 0.20 and 0.39 SD score units (all p<0.001). The standard deviation scores for WC increased much more than for BMI (0.34 units vs 0.08 units for boys and 0.39 units vs 0.20 units for girls). Conclusions: The average value of BMI and WC among primary and secondary school students has increased dramatically from 2005 to 2010 in Anhui, China. Changes in WC have greatly exceeded those in BMI, showing that WC is a good proxy for central fatness rather than BMI.