Spatiotemporal trends and associated factors of overweight and obesity among Chinese children aged 3 to 6 years

Abstract

Objective To describe the temporal trends and spatial patterns of overweight and obesity among Chinese children aged 3 - 6 years from 2000 to 2020 across urban-rural settings and regions with different epidemic levels, and to examine associated factors and their interaction effects using cross-sectional data from 2020, so as to provide scientific reference for making strategies for the prevention and control of childhood obesity. Methods Data on children aged 3 - 6 years were obtained from five rounds of the National Physical Fitness Surveillance conducted in 2000, 2005, 2010, 2014, and 2020. Spatiotemporal trends in overweight and obesity were described. Multilevel logistic regression models were used to examine the associations of urbanization level, family environment, and individual behavioral factors with overweight/obesity, and to test interaction effects. Results From 2000 to 2020, the prevalence of overweight and obesity among Chinese children aged 3 - 6 years increased from 15.8% to 23.8%, while the prevalence of obesity alone rose from 3.9% to 7.2%. The increase was greater in rural than in urban areas, resulting in a gradual narrowing of the urban-rural gap. Substantial regional difference was observed: prevalence remained consistently high and increased steadily in high-prevalence regions, increased most rapidly in medium-prevalence regions, and rose more slowly in low-prevalence regions. Urbanization level was positively associated with the risk of overweight/obesity (OR=1.008, P＜0.05). Older age (OR=1.233), boys (OR=1.232), and longer screen time were all associated with a higher risk of overweight/obesity (P < 0.05). Compared with screen time of <20 min/d, screen time of 20 - 40 min/d(OR=1.128) and >40 min/d(OR=1.276) was significantly associated with an increased risk of overweight/obesity (P < 0.05). Interaction analysis further showed that the association between screen time and overweight/obesity was stronger in regions with an urbanization rate of ≥70%(P<0.05). Conclusions The prevalence of overweight and obesity among Chinese children aged 3 - 6 continues to rise, with significant disparities in growth rates observed across urban-rural areas and different geographic regions. Childhood obesity is driven by the interplay between urbanization-related environmental factors and individual behaviors. Future prevention and control strategies should prioritize household and individual interventions while strengthening structural environmental improvements, thereby promoting a comprehensive intervention pathway characterized by environment-behavior synergy.

Keywords

overweight / obesity / urbanization / interaction effect / screen time / children