农村学龄儿童膳食多样性与营养状况关联性

为了解中国农村学龄儿童膳食多样性与以年龄别体质指数Z评分衡量的多种营养不良形式之间的关系，利用中国5省(市、自治区)12 508名农村学生的微观截面数据，建立多元线性回归模型和Probit模型进行系数估计；以性别、年龄、膳食多样性评分(Dietary diversity score，DDS)水平划分亚组分析组间差异性，并探究用于构建DDS的具体食物组对营养状况的可能影响。结果表明:1)提高农村学龄儿童膳食多样性水平能够降低其营养不良风险，此影响具有组间异质性；提高低DDS水平亚组的膳食多样性，有助于降低营养不足率；提高中高DDS水平学生的膳食多样性，有助于降低超重肥胖风险；2)提高膳食多样性对降低超重肥胖风险的作用在女生和9~11岁学生中表现更为显著。据此，建议在进一步推进营养改善计划时，加强对学生照料人和营养配餐单位的营养健康教育，丰富学生膳食大类和细类的多样性水平；并在制定学龄儿童营养改善政策时，更多关注女孩和学龄初期儿童。

Correlation between the dietary diversity and nutritional status of rural school-age children

To investigate the correlation between the dietary diversity of rural school-age children and multiple forms of malnutrition assessed by body mass index-for-age z-score, a cross-section data on 12 508 rural students from five Chinese provinces was used and the multiple linear regression and probit models were applied. The heterogeneous effects of gender, age and dietary diversity score(DDS)levels were estimated, and the food groups(constituting DDS)influence pathways were explored. The results show that: 1)Increasing the dietary diversity of rural school-age children can reduce the risk of malnutrition, and this effect is heterogeneous among subgroups. In specifically, for subgroups with the lowest- DDS, increasing the dietary diversity can help reduce the rate of malnutrition. For subgroups with medium- and high- DDS, it can help reduce the risks of overweight and obesity. 2)The effect of increasing dietary diversity on reducing the risk of overweight and obesity is more significant in girls and 9 to 11 years old groups. In conclusion, to promote nutrition improvement plans, the nutrition and health education for student caregivers and nutrition catering units should be strengthened, since the diversity of students'' dietary categories and subcategories should be enriched. Besides, more attention should be paid to girls and early school-aged children when formulating policies to improve nutrition for school-age children.