Associations between dietary inflammatory index and cardiovascular kidney metabolic syndrome: insights from NHANES 2005–2018

Cardiovascular–kidney–metabolic syndrome (CKM) is recognized as a dynamic systemic disorder. Inflammation is pivotal in CKM syndrome development. The dietary inflammatory index (DII) represents a well-validated tool to quantify the overall inflammatory potential of an individual diet. However, the association between DII and CKM syndrome remains undetermined. We analyzed data from 10,600 adults aged ≥ 20 years from the National Health and Nutrition Examination Survey (NHANES 2005–2018). The CKM stages were classified on the basis of metabolic risk factors, cardiovascular disease (CVD), and chronic kidney disease (CKD). Our findings indicated that advanced CKM stages overlapped with high-DII profiles. The findings derived from the four multivariable logistic regression analysis models revealed a significant positive correlation between a continuous DII and the incidence of advanced CKM syndrome. Additionally, the quartiles of the DII demonstrated a statistically significant association with an increased incidence of advanced CKM syndrome in the fully adjusted models (DII Q4 vs. Q1, odds ratio = 1.44, 95% confidence interval = 1.08–1.92, P =0.014). The results of restricted cubic spline (RCS) analysis suggested a linear and positive correlation between DII and advanced CKM syndrome. Subgroup analyses further revealed sex-, depression-, and sleep disorder-specific effects. This study indicates that the DII may be a modifiable lever in CKM syndrome management, bridging dietary inflammatory patterns with systemic metabolic and cardiovascular diseases.