Time Trend and Demographic and Geographic Disparities in Childhood Obesity Prevalence in China-Evidence from Twenty Years of Longitudinal Data

Abstract

Childhood overweight and obesity (ow/ob) has become a serious threat to many countries, including China. However, limited evidence was obtained from longitudinal data in China. This study examined the secular trends and geographic variation in the prevalence of ow/ob and obesity only, and age, gender, and urban-rural disparities among school-aged children across China. Data from children aged 6-17 surveyed in China Health and Nutrition Survey (CHNS) from 1991 (n = 2712) to 2011 (n = 1054) were used. Overweight and obesity were defined based on the International Obesity Task Force (IOTF) recommended Asian age-sex-specific BMI cut-off-points. We found that: (1) childhood ow/ob and obesity prevalence increased from 11.7% to 25.2% and from 2.8% to 10.1% during 1991-2011, respectively; (2) children aged 6-12 experienced a 1.3 and 1.6 times increase in ow/ob and obesity prevalence than children aged 13-17, respectively; (3) the urban-rural gap in ow/ob prevalence widened; (4) ow/ob prevalence in boys was higher and increased faster than in girls, especially in an urban setting; and (5) geographic variation was observed with faster increases in more economically developed east, central and northeast regions than in the less developed west. The findings added more nuances to the picture of temporal changes in ow/ob prevalence among Chinese children.

Keywords: China; child; obesity; overweight.

Figure 1

Nine Chinese provinces in which China Health and Nutrition Survey (CHNS) was conducted, with the combined prevalence (%) of overweight and obesity calculated for each survey year among children aged 6–17 sampled in each province, where overweight and obesity were defined based on the 2012 IOTF recommended age-sex-specific cut-offs corresponding to BMI ≥ 23 and ≥ 27 at age 18, respectively [14].

Figure 2

Time trend (1991 to 2011) and disparities across population groups in combined prevalence of overweight and obesity (ow/ob) and prevalence of obesity among children aged 6–17 in China, where overweight and obesity were defined based on the 2012 IOTF recommended age-sex-specific cut-offs corresponding to BMI ≥ 23 and ≥ 27 at age 18, respectively [14]: (a) ow/ob prevalence by age group; (b) ow/ob prevalence by gender and urbanicity, separately; (c) ow/ob prevalence by gender and urbanicity; (d) ow/ob prevalence by region; (e) obesity prevalence by age group; (f) obesity prevalence by gender and urbanicity, separately; (g) obesity prevalence by gender and urbanicity; (h) obesity prevalence by region.