Time trends of obesity in pre-school children in China from 1989 to 1997

Objective: To examine predictors and time trends of obesity in pre-school children in China. Design: This study was based on data from China Health and Nutrition Survey, a longitudinal survey from 1989 to 1997. Subjects: For cross-sectional analysis, we included 944, 1058, 903 and 483 children aged 2 - 6 y in 1989, 1991, 19913 and 1997, respectively. For longitudinal analysis, we included 944 children and 3146 measurements during four time periods. Measures: Overweight and obesity according to age- and sex-specific BMI cut-off points proposed by International Obesity Task Force. Results: The overall prevalence of obesity increased from 4.2% in 1989 to 6.4% in 1997 among children aged 2-6y. The increase largely occurred in urban areas, where the prevalence of obesity increased from 1.5% in 1989 to 12.6% in 1997 and prevalence of overweight increased from 14.6 to 28.9% at the same period. Longitudinal analysis shows BMI increased by 0.2 kg /m(2) per year in urban areas and 0.1 kg/m(2) per year in rural areas. In multivariate analysis, overweight in early childhood (2-6y), parental overweight, high income and urban areas independently predicted overweight at age 10-14y. Conclusion: A substantial increase in overweight and obesity among children aged 2-6y was observed in urban areas in China from 1989 to 1997. Overweight in early childhood significantly predicted overweight during adolescence. Urgent public health strategies are needed to prevent childhood obesity in China.