Abstract
The Ying Yang Bao (YYB) intervention, a national policy in China, has been implemented for over two decades. Most previous studies have focused only on the short-term effects of YYB, while the long-term effects remain unexplored. This study was designed to evaluate the long-term effects of YYB in children aged 6-60 months. A sample of 4666 children was divided into intervention and control groups. Information on basic characteristics, physical examination, YYB consumption, etc., was obtained annually from 2018 to 2021. T-tests or chi-square tests were used to compare differences between the groups for continuous or categorical variables. Children in the intervention group showed greater incremental improvements in hemoglobin levels and physical development (p < 0.05). Prevalence of anemia, underweight, and stunting were lower in the intervention group than in the control group (all p < 0.05). Two-level regression models were constructed to assess the long-term effects of YYB. YYB reduced the risk of anemia and wasting by 37% (OR: 0.63, 95% CI: 0.52-0.75) and 49% (OR: 0.51, 95% CI: 0.39-0.67), respectively. This study indicates that YYB could significantly improve the nutritional status of children aged 6-60 months in underdeveloped rural areas of China.