[Changes in the distribution of body mass index among aged children 6-17 in China from 1991 to 2006].

OBJECTIVE: To describe changes in the distribution of body mass index among Chinese children in China from 1991 to 2006. METHODS: This paper was based on data collected in the China Health and Nutrition Survey in 1991 and 2006, and the subjects were 6- 17-years-old. Tukey mean-difference plots were used to investigate the changes in the distribution of BMI within sex-age groups. RESULTS: The distribution of BMI among Chinese children in 2006 was different from that in 1991 for all sex-age groups, there was increasing positive skewness with a greater shift in the upper part of the distribution. CONCLUSION: The children in the upper part of the BMI distribution may be more susceptible to the changes of environment than those in the lower parts. So the causes for the increase in obesity should be sought in part at the population level than focusing on individuals.