The Relationship between Obesity, Sleep and Physical Activity in Chinese Preschool Children

BACKGROUND Pediatric overweight and obesity has become a major public health problem in China. The goal of this study is to understand overweight and obesity in preschool children in Changsha City in the context of their sleep and physical activity. These results offer feasible proposals to reduce levels of overweight and obesity among preschool children. METHODS A total of 112 preschoolers aged three to six years old were investigated using multiple stage stratified cluster sampling and simple random sampling. Questionnaires were used to collect general information about children and their families. Body mass index (BMI) was used as an indicator of overweight and obesity. Age- and sex-specific cutoff values for Chinese children and adolescents were used to determine child weight status. Children's sedentary time was reported by caregivers, while physical activity and sleep were recorded using fitness bracelets (Misfit Shine 2). RESULTS The prevalence of childhood overweight and obesity were 15.2% and 9.8% respectively. Preschool-aged children travelled 11,111 ± 3357 and 10,350 ± 2973 steps per day on weekdays and weekends respectively. The number of daily steps was not statistically different between weekdays and weekends. The amount of time spent daily doing vigorous activity on weekdays and weekends was significantly different, with an average time of 20.5 ± 31.6 min and 10.3 ± 15.3 min respectively (p = 0.002). Furthermore, 10.7% and 50.9% of children used screens for more than two hours on weekdays and weekends respectively (p < 0.001). Children slept for significantly longer on weekends (8.3 ± 0.9 h) than on weekdays (8.1 ± 0.7 h) (p = 0.037). A significantly higher proportion of students also fell asleep before 10:00 p.m. on weekends (26.8%) compared to weekdays (15.2%) (p < 0.001). Parent's BMI values were positively correlated with child BMI, the monthly household income was negatively associated with child BMI. Male children were more likely to have a higher BMI than female children. Children who were obese were also more likely to have shorter sleep times compared to children of normal weight (p = 0.047). CONCLUSIONS There was a high prevalence of overweight and obesity among the Chinese preschool children in this study. Students also demonstrated poor sleep and physical activity habits. Future research is necessary to explore the relationship between sleep, physical activity and weight status for young children in China.