Dietary inflammatory index and all-cause mortality in large cohorts: The SUN and PREDIMED studies

Clin Nutr. 2019 Jun;38(3):1221-1231. doi: 10.1016/j.clnu.2018.05.003. Epub 2018 May 24.

Abstract

Background: Inflammation is known to be related to the leading causes of death including cardiovascular disease, several types of cancer, obesity, type 2 diabetes, depression-suicide and other chronic diseases. In the context of whole dietary patterns, the Dietary Inflammatory Index (DII®) was developed to appraise the inflammatory potential of the diet.

Objective: We prospectively assessed the association between DII scores and all-cause mortality in two large Spanish cohorts and valuated the consistency of findings across these two cohorts and results published based on other cohorts.

Design: We assessed 18,566 participants in the "Seguimiento Universidad de Navarra" (SUN) cohort followed-up during 188,891 person-years and 6790 participants in the "PREvencion con DIeta MEDiterránea" (PREDIMED) randomized trial representing 30,233 person-years of follow-up. DII scores were calculated in both cohorts from validated FFQs. Higher DII scores corresponded to more proinflammatory diets. A total of 230 and 302 deaths occurred in SUN and PREDIMED, respectively. In a random-effect meta-analysis we included 12 prospective studies (SUN, PREDIMED and 10 additional studies) that assessed the association between DII scores and all-cause mortality.

Results: After adjusting for a wide array of potential confounders, the comparison between extreme quartiles of the DII showed a positive and significant association with all-cause mortality in both the SUN (hazard ratio [HR] = 1.85; 95% CI: 1.15, 2.98; P-trend = 0.004) and the PREDIMED cohort (HR = 1.42; 95% CI: 1.00, 2.02; P-trend = 0.009). In the meta-analysis of 12 cohorts, the DII was significantly associated with an increase of 23% in all-cause mortality (95% CI: 16%-32%, for the highest vs lowest category of DII).

Conclusion: Our results provide strong and consistent support for the hypothesis that a pro-inflammatory diet is associated with increased all-cause mortality. The SUN cohort and PREDIMED trial were registered at clinicaltrials.gov as NCT02669602 and at isrctn.com as ISRCTN35739639, respectively.

Keywords: CRP; Cohort studies; Dietary inflammatory index; Inflammation; Mediterranean diet; Mortality.

Publication types

  • Meta-Analysis
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Body Mass Index
  • C-Reactive Protein
  • Diabetes Mellitus, Type 2 / epidemiology
  • Diet / mortality*
  • Diet / statistics & numerical data
  • Diet, Mediterranean / statistics & numerical data*
  • Female
  • Humans
  • Inflammation / mortality*
  • Male
  • Middle Aged
  • Obesity / epidemiology
  • Patient Compliance / statistics & numerical data
  • Prospective Studies
  • Randomized Controlled Trials as Topic
  • Risk Factors
  • Smoking / epidemiology
  • Young Adult

Substances

  • C-Reactive Protein

Associated data

  • ClinicalTrials.gov/NCT02669602
  • ISRCTN/ISRCTN35739639