Purpose Understanding the prevalence and trends of obesity in preschool children is of critical importance for public health policy. Thus, the object of the present study was to assess the prevalence and trends of obesity in Chinese preschool children from 1996 to 2019, and to examine the differences among different population according to year, gender, age, urban/rural and geographical area.Methods Four online databases (Chinese National Knowledge Infrastructure, Wanfang Data Resource System, Weipu Chinese Journal Service Platform and PubMed) were searched for studies published from January 1990 to May 2019 using predefined inclusion/exclusion criteria. Random effects meta-analysis was used to calculate the prevalence of obesity.Results Forty-three studies with a total of 765,255 Chinese preschool children aged 3-6 years were included in this meta-analysis. The prevalence of obesity in the whole sample was 6.41% (95%CI: 5.74%-7.78%, P < 0.000, I-2 = 99.79%; obtained after trim-and-fill adjustment). There was no significant difference (P = 0.222) in the prevalence of obesity during five periods (1996-2000, 2001-2005, 2006-2010, 2011-2015, 2016-2019). The obesity prevalence of boys was higher than girls (P = 0.007), and the obesity prevalence increased with age (P = 0.000). In 2006-2010, the prevalence of obesity among urban areas was about three times than that of rural areas (P = 0.001). However, the difference was decreased during 2011-2015 (P = 0.788). In rural areas, the obesity prevalence in 2011-2015 was two times more than that in 2006-2010 (P = 0.005). Geographical area was a strong determinant of heterogeneity for Chinese preschool children (P = 0.001).Conclusion There was no significant difference of the obesity prevalence among any five-year periods from 1996 to 2019. The prevalence of obesity in boys was higher than girls and increased with age. Though the prevalence of obesity in rural area was lower than the urban area, the speed of the increasing of the prevalence after 2010 in rural area should be noted. Public health intervention such as physical activity promotion and nutrition education should be conducted on preschool children for obesity prevention to promote their healthy development.
