The Diet Quality Index-International (DQI-I) provides an effective tool for cross-national comparison of diet quality as illustrated by China and the United States.
A composite measure of diet has been preferred to an index of a single nutrient or food in the area of dietary assessment. However, the lack of such a tool for cross-national comparisons has restricted the ability to compare diet quality between countries using an overall measure of diet. In this study, we created a tool called the Diet Quality Index-International (DQI-I) for global monitoring and exploration of diet quality across countries. The major categories of the index components are variety, adequacy, moderation and overall balance. Using the tool, this research presents a cross-national comparison of diet quality between China and the United States, incorporating comparable national in-depth diet data. The mean of the DQI-I score was slightly higher in China than in the United States. By major categories of the DQI-I, dietary variety was better achieved in the U.S. diet; moderation and overall balance of intakes were better accomplished in China. The DQI-I was successful in capturing variability in intakes of food and nutrients in both countries. Some distinct patterns of poor quality diet in each country were also identified. As demonstrated in this study, the DQI-I provides an effective means of cross-national comparative work for global understanding of diet quality. Furthermore, the dietary problem areas identified by the DQI-I may be useful in guiding the development of programs to improve public health.