Association between the dietary inflammatory index and all-cause mortality in the U.S. cancer survivors: A prospective cohort study using the National Health and Nutrition Examination Survey database.

Background: Cancer remains one of the leading causes of mortality worldwide. Diet can impact inflammation and consequently affect cancer outcomes. The Dietary Inflammatory Index (DII) can serve as a tool to assess the inflammatory potential of cancer survivors' diets and further predict their survival. Objectives: To investigate the relationship between the DII and the survival of cancer survivors in National Health and Nutrition Examination Survey (NHANES). Methods: An overall sample of 2359 U.S. cancer survivors from the 2005-2014 cohorts of the NHANES were studied. The DII scores were calculated using 28 dietary components and the mortality status was ascertained until December 31, 2015. Based on the multiple analyses, the relationship between DII and all-cause mortality was examined. Results: The weighted mean age at baseline was 65.17 ± 14.46 years, 53.16 % were female and 71.30 % were non-Hispanic white. The average DII was 1.51 ± 1.97. After accounting for multiple covariates, positive associations were observed (P < 0.01). Based on Kaplan-Meier survival curves, their significant relationship remains same and the survival probability was decreased among the groups of anti-inflammatory diets (DII < 0) versus pro-inflammatory diets (DII ≥ 0) significantly (Log rank test; P = 0.03). Further analyses were conducted on subgroups and the results are still robust. Conclusions: An elevated DII was associated with a rising mortality rate among cancer survivors. DII might serve as a potential inflammatory predictor of cancer mortality prognosis, as well as guide nutritional care and even clinical treatment of cancer survivors.