A Novel Dietary Inflammatory Score and Risk of Incident Chronic Kidney Disease

Background: Inflammation contributes to the onset of chronic kidney disease (CKD). Diet is a modifiable risk factor for CKD; however, it remains unknown if the inflammatory potential of the diet is prospectively associated with CKD risk in healthy individuals. Methods: In 9,814 participants (mean age: 60 years) free of CKD in the Atherosclerosis Risk in Communities (ARIC) Study at visit 3 (1993-1995), we developed a novel empirically-derived, food-based, dietary inflammatory score (Comprehensive Dietary Inflammation Index, CDII) from a random two-thirds sample (N=6,542, discovery) and validated in the remaining one-third sample (N=3,272, validation). Reduced rank regression with 13 inflammatory biomarkers as the response variables and 31 food groups as the independent variables was used to develop the CDII. Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CI%) and test the association between the CDII and incident CKD, adjusting for important confounders. Results: The CDII included eight food groups (four pro-inflammatory and four anti-inflammatory), with a higher score representing a more pro-inflammatory diet. In the validation sample, the CDII was positively correlated with most pro-inflammatory proteins (C-reactive protein, interferon-γ, interleukin-8, interleukin-6, and monocyte chemoattractant protein-1) and negatively correlated with adiponectin. However, the CDII was positively associated with one anti-inflammatory protein (transforming growth factor-β). Over a median-follow-up of 19 years (mean follow-up of 18 years), 3,293 participants developed CKD. A diet that was the most vs. least concordant with the CDII (quartile 4 vs. quartile 1) had 28% greater risk of incident CKD (HR: 1.28, 95% CI: 1.15, 1.43, P trend<0.001). Conclusions: A novel diet score, representing its inflammatory potential, was associated with a higher risk of developing CKD. Reducing consumption of pro-inflammatory diet may be a strategy to prevent CKD.