The relationship between composite dietary antioxidant index and odds of depression: A systematic review and dose-response meta-analysis of observational studies.
BACKGROUND: Recently, the association between the composite dietary antioxidant index (CDAI) score and depression has received special attention from researchers. However, this possible association has not been comprehensively examined. Thus, the present study aims to comprehensively assess the relationship between CDAI score and depression odds. METHODS: A thorough literature search was performed using Scopus, PubMed, and Web of Science up to November 2025. Observational studies assessing the relationship between CDAI score and depression odds were included. The odds ratios (ORs) and their 95% confidence intervals (CIs) reported in each study were extracted, and a pooled effect size was calculated using a random-effects model with inverse-variance weighting. RESULTS: Four observational studies were included in the current systematic review and meta-analysis. The pooled effect size indicated that a higher CDAI score was associated with lower odds of depression (OR:0.62; 95%CI: 0.51-0.76, I2 = 48.5%; P-value = 0.121). In an exploratory linear dose-response analysis based on two eligible studies, no significant association was observed between a one-unit increase in CDAI score and the odds of depression (OR = 0.96; 95% CI: 0.91-1.02; I2 = 92.2%; P-value<0.001). Given the limited number of studies and substantial heterogeneity, these findings should be interpreted cautiously. CONCLUSIONS: Our findings suggest that higher CDAI scores, reflecting greater adherence to antioxidant-rich dietary patterns, are associated with lower odds of depression.