Development and Validation of the China Dietary Inflammatory Index (CHINA-DII)

Objective: To develop and validate the China Dietary Inflammatory Index (CHINA-DII) for Chinese adults. Methods: A systematic literature search was conducted to identify studies published between 2009 and 2024 reporting dietary intake levels among Chinese adults. After applying inclusion and exclusion criteria and evaluating study quality, a dietary intake database for Chinese adults was established. Following the methodology of the original Dietary Inflammatory Index (DII), the CHINA-DII was constructed and validated. A total of 256 newly diagnosed gastric cancer patients who visited the Union Hospital of Fujian Medical University between June 2023 and November 2024 were recruited. Demographic information, clinical data, and dietary data based on a food frequency questionnaire (FFQ) were collected. Spearman rank correlation was used to assess the relationship between CHINA-DII scores and high-sensitivity C-reactive protein (hs-CRP) levels. Results: A total of 33 eligible studies were included to develop a dietary intake database encompassing 27 dietary components. Among the 256 gastric cancer patients, the average CHINA-DII score was -1.91 ± 0.35, and the mean hs-CRP level was 3.68 ± 2.35 mg/L. CHINA-DII scores were positively correlated with hs-CRP levels (r = 0.20, p ≤ 0.001). Multivariate logistic regression analysis showed that individuals with higher CHINA-DII scores had a 1.90-fold increased risk of hs-CRP ≥ 3 mg/L compared to those with lower scores (odds ratio, OR = 1.90; 95% confidence interval, 95%CI: 1.01-3.55). For each 1-standard-deviation (SD) increase in CHINA-DII score, the risk of hs-CRP ≥ 3 mg/L increased by 1.50 times (OR = 1.50, 95% CI: 1.10-2.06). Conclusions: The CHINA-DII developed in this study effectively reflects the potential inflammatory impact of dietary intake in Chinese adults and is significantly positively associated with the inflammatory marker hs-CRP, indicating good validity and applicability.