Novel Dietary Inflammatory Score and Risk of Incident CKD

Background Inflammation contributes to the onset of 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 9814 participants (mean age: 60 years) free of CKD in the Atherosclerosis Risk in Communities 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 (N56,542, discovery) and validated in the remaining one-third sample (N53,272, 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 and 95% confidence intervals and test the association between the CDII and incident CKD, adjusting for important confounders. Results The CDII included eight food groups (four proinflammatory and four anti-inflammatory), with a higher score representing a more proinflammatory diet. In the validation sample, the CDII was positively correlated with most proinflammatory proteins (C-reactive protein, interferon-g, IL-8, IL-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-b). Over a median follow-up of 19 years (mean follow-up of 18 years), 3293 participants developed CKD. A diet that was the most versus least concordant with the CDII (quartile 4 versus quartile 1) had 28% greater risk of incident CKD (hazard ratio, 1.28; 95% confidence interval, 1.15 to 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 proinflammatory diet may be a strategy to prevent CKD.