Association Between Dietary Inflammatory Index and Depression Symptoms in Chronic Kidney Disease

Objective: The study is aimed at investigating the relationship between dietary inflammatory index (DII) score and depression symptoms in chronic kidney disease (CKD), exploring its potential role as an indicator of depression risk and offering new insights into dietary interventions for this vulnerable population. Materials and Methods: The cross-sectional investigation included CKD patients aged ≥ 18 in the 2007-2018 National Health and Nutrition Examination Survey. The Patient Health Questionnaire-9 (PHQ-9) was administered to evaluate depression symptoms. Dietary information was obtained from a 24-h dietary recall interview. The relationship between DII and depression was explored through weighted univariate and multivariate logistic regression models, adjusting for relevant covariates identified via backward selection. Results were expressed as odds ratios (ORs) with 95% confidence intervals (CIs). To further investigate the association, restricted cubic spline (RCS) and subgroup analyses were conducted. Results: Totally, 489 (11.55%) patients with CKD had depression symptoms. A high DII score was linked to elevated depression symptoms incidence in CKD (OR: 1.67, 95% CI: 1.06-2.65). Adjusting all covariates, the relationship between DII score and depression symptoms still existed in patients aged ≥ 60 years (OR: 1.80, 95% CI: 1.16-2.79), males (OR: 2.05, 95% CI: 1.16-3.59), smokers (OR: 1.70, 95% CI: 1.06-2.75), and those without sleep disorders (OR: 1.81, 95% CI: 1.01-3.23). Conclusion: DII score was associated with depression symptoms in patients with CKD. The findings suggest that diet plays a role in mental health, particularly in chronic conditions like CKD. The results underscore the importance of exploring anti-inflammatory dietary interventions to mitigate depression symptoms in this population. Further longitudinal research is necessary to establish causality and determine the efficacy of targeted dietary modifications in CKD patients with depression. Limitations: As a cross-sectional study, causality cannot be inferred from these findings. Additionally, the reliance on self-reported dietary data may introduce bias, and unmeasured confounders could influence the observed associations.