Further increase of obesity prevalence in Chinese children and adolescents--cross-sectional data of two consecutive samples from the city of Shanghai from 2003 to 2008.

OBJECTIVE: Putative changes in the prevalence of obesity in Chinese children and adolescents in Shanghai, one of the most urbanized areas in China, were analyzed in a cross-sectional manner in 2003-2008.
METHODS: One urban and one suburban district were randomly selected. 70,582 students in 2003 and 86,355 students in 2008 from schools from within the two districts were examined. Anthropometric parameters were measured in all. Adiposity status was estimated using body mass index according to International Obesity Task Force standards. The prevalence of obesity was analyzed.
RESULTS: The standardized prevalence of overweight significantly increased from 12.75 to 14.2% (p < 0.01), and the prevalence of obesity significantly increased from 3.35 to 3.94% (p < 0.01) during the study period. In contrast to data from developed countries, the prevalence of obesity decreased with age in both boys and girls. The prevalence of obesity and overweight in boys was significantly higher than that in girls (p < 0.01). Interestingly, the prevalence of overweight and obesity in the urban area was also significantly higher than that in suburb area (p < 0.01).
CONCLUSION: Over a 5-yr period, there was a significant increase in the prevalence of obesity in children and adolescents in Shanghai. The high percentage of overweight and obesity in the young age groups is of particular concern. Urbanization might be a causative factor for the increase in obesity prevalence in Chinese children in the Shanghai area.