Association of dietary inflammatory index and all-cause and cardio- cerebrovascular mortality in atherosclerotic cardiovascular disease survivors: a cohort study from NHANES analysis

Objective: To evaluate the association between dietary inflammatory index (DII) and all-cause and cardio-cerebrovascular mortality in patients with atherosclerotic cardiovascular disease (ASCVD). Methods We collected data from National Health and Nutrition Examination Survey (NHANES) between 1999 and 2018. The chi-square test was performed to evaluate the association between pro-inflammatory diets (DII > 0) and anti-inflammatory diets (DII < 0) participant groups. Cox regression models were used to investigate the association between DII and all-cause and cardio-cerebrovascular mortality. We also used a restricted cubic spine RCS model to explore the possible non-linear association between DII and mortality. Meanwhile, we investigated the potential interaction between multiple stratification factors and DII. Results A total of 4264 participants with 58.75% were male included, of which 3201 were over 60 years old. During the median follow-up period of 83 months, a total of 1784 participants had died from any cause. All-cause mortality of the pro-inflammatory diet group (38.26%) was significantly higher than the anti-inflammatory diet group (30.95%). In three models, DII was significantly associated with an elevated risk of cardio-cerebrovascular mortality. We developed RCS models and found evidence of a non-linear correlation between DII and all-cause mortality and cardio-cerebrovascular mortality, P for non-linearity was 0.048 and 0.008, respectively. Finally, we analyzed the DII across risk factor subgroups linked to stroke, and no significant disparities were identified. Conclusion Our study revealed a protential non-linear association between DII and all-cause mortality and cardio-cerebrovascular mortality in ASCVD survivors.