Time trends and disparities in combined overweight and obesity prevalence among children in China.

This study aims to examine the trends and disparities in the combined prevalence of overweight and obesity among children in China by regions and specific groups over the last 30 years. PubMed, Wanfang, CNKI, VIP database, official websites of national governments and professional institutions/associations were systematically searched, for related reports and studies published up until December 2021. Reports based on nationally representative survey data were also examined and included. In mainland China, overweight and obesity decreased in pre-school children (≤6 years old) and increased in school-aged children (7-18 years old) between 2010 and 2013 to 2015 and 2017, but long-term trends predict future increases in both groups. The prevalence of overweight and obesity in primary school students in Hong Kong dropped from 21.4% in 2007-2008 to 17.6% in 2016-2017. In Macao, the prevalence of overweight and obesity in children aged 6-18 years was reported by age stratification; the lowest and highest prevalence was 13.4%, 29.3% and 9.2%, 21.7% for boys and girls in latest survey in 2015, respectively. The prevalence of overweight and obesity in primary, middle and high school students in Taiwan dropped from 28.2%, 27.1% and 31.1% in 2010 to 26.7%, 25.2% and 26.7% in 2013, respectively. Furthermore, in mainland China, the prevalence in rural left-behind boys and girls was 10.7% and 7.0%, respectively, in 2011, and the prevalence among migrant pre-school children was about 5.0% around 2010. In summary, the prevalence of overweight and obesity in school-aged children has increased in mainland China and Macao, but decreased in Hong Kong and Taiwan prior to 2017. The projections suggest that the highest prevalence of overweight and obesity in pre-school children will be in rural children in the future. These factors need to be considered when formulating and implementing national policies and programmes to fight overweight and obesity.