Association between dietary inflammatory index and cardiovascular–kidney–metabolic syndrome risk: a cross-sectional study

Dietary inflammation has been linked to various diseases. The dietary inflammatory index (DII) is a tool used to assess the inflammatory potential of a diet. The aim of this study was to explore the relationship between the DII and the risk of developing cardiovascular-kidney-metabolic syndrome (CKMS) in a U.S. Cross-sectional data from the National Health and Nutrition Examination Survey (NHANES) from 2001 to 2020, which included 24,071 participants, were analyzed. CKMS was defined as the coexistence of cardiometabolic syndrome (CMS) and chronic kidney disease (CKD). The DII was calculated on the basis of the anti-inflammatory and pro-inflammatory scores of foods and nutrients. Weighted multivariable logistic regression models were used to estimate the associations between the DII and the risk of developing CKMS. Restricted cubic spline (RCS) regression was conducted to test nonlinear relationships. Subgroup analyses were performed by sex, age, race, smoking status, and alcohol consumption status. After adjusting for confounders, compared with those of the lowest quartile of the DII, the adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for higher DII quartiles were 1.17 (0.93-1.47), 1.43 (1.13-1.81), and 1.76 (1.42-2.18), respectively. Each one-unit increase in the DII was associated with a 12% greater risk of developing CKMS (OR: 1.12, 95% CI: [1.08, 1.18]). RCS regression indicated a significant nonlinear positive association between the DII and the risk of developing CKMS. This study revealed a nonlinear positive association between the DII and the risk of developing CKMS in the U.S. Further longitudinal studies are needed to establish causality and explore the underlying biological mechanisms involved.