Prevalence and Influencing Factors of Overweight and Obesity Among Left-Behind Children Under 6 Years Old in China: A Cross-Sectional Study

<b>Objectives</b>: To analyze the prevalence and influencing factors of overweight and obesity among left-behind children (LBC) under 6 years old in China, and to provide a reference basis for their early prevention and control. <b>Methods</b>: The data were derived from the National Nutrition and Health Survey among children and lactating mothers (2016-2017). A total of 19,229 left-behind children under 6 years old in China were included in this study. The results were post-stratification weighted and adjusted using data from the Sixth National Population Census released by the National Bureau of Statistics of China in 2010. The Rao-Scott chi-square test with sampling design-weighted correction was used to test for statistical differences, and multivariate unconditional logistic regression analysis was conducted to explore influencing factors. <b>Results</b>: The prevalence of overweight and obesity among LBC under 6 years old in China were 6.68% and 2.22%, respectively. The overweight rate and obesity rate of boys were higher than those of girls (7.96% vs. 5.15%, 2.77% vs. 1.56%). Both the overweight rate and obesity rate showed a "U"-shaped trend with increasing age (<i>p</i> < 0.0001). LBC with migrant fathers had the highest overweight rate and obesity rate. Logistic regression analysis indicated that being male, being in infancy or preschool age, residing in eastern China, having a migrant father, and higher annual per capita household income were risk factors for overweight and obesity. <b>Conclusions</b>: Left-behind children under 6 years old in China are at risk of overweight and obesity. Among LBC under 6 years old in China, the issues of overweight and obesity are relatively prominent in boys, as well as those in infancy and preschool age. Additionally, LBC with fathers who migrate for work have relatively higher overweight/obesity rates. It is essential to pay attention to the problems of overweight and obesity among LBC under 6 years old in China, strengthen the monitoring of their growth and development, and incorporate the improvement of overweight and obesity in LBC into national nutrition improvement policies at all levels.