Dietary Inflammatory Index (DII) and Cancer Outcomes: A Systematic Review and Meta-Analysis

Authors:

Mackenzie Fowler (Presenter)
University of Alabama at Birmingham

Tomi Akinyemiju, University of Alabama at Birmingham

Public Health Statement: Should the Dietary Inflammatory Index (DII) prove useful in predicting pro-inflammatory diets associated with increased risk, incidence, and mortality cancer outcomes, it may be used clinically to identify at-risk populations and intervene prior to the development of negative cancer outcomes.

Purpose: Pro-inflammatory diets, consisting of food items high in fats and low in antioxidants, have been associated with increased risk and mortality due to cancer. We present a systematic review and meta-analysis of the current published literature on a novel Dietary Inflammatory Index (DII) score and its association with cancer risk and mortality outcomes.

Methods/Approach: Published articles from three online databases (PubMed, Scopus, and Embase) examining the association between DII and any cancer risk, incidence, or mortality between 1980 and October 2016 were selected for review. Results of studies meeting our inclusion criteria were summarized and meta-analysis was conducted using STATA to generate summary measures of association across studies.

Results: There were 63 published articles identified from the online search, and following title, abstract and full text review, twenty-four studies were included and met the inclusion criteria. All of the articles utilized the same measure and formula for the DII based on information from Food-Frequency Questionnaires. Of the 24 studies, 13 were case-control, 6 were prospective cohort and examined cancer incidence, and 2 assessed cancer mortality. The most common cancer types examined were colorectal, breast, lung, and prostate. Higher DII was associated with 25% increased risk of cancer incidence (RR: 1.24, 95% CI: 1.14–1.35), 75% higher odds of cancer (OR: 1.75, 95% CI: 1.43–2.16) and 67% increased risk of cancer mortality (RR: 1.67, 95% CI: 1.13–2.48). When examined by cancer type, higher DII was associated with 12% increased risk of breast cancer (RR: 1.12, 95% CI: 1.03–1.22), 33% increased risk of colorectal cancer (RR: 1.33, 95% CI: 1.22–1.46), and 30% increased risk of lung cancer (RR: 1.30, 95% CI: 1.13–1.50).

Conclusions/Implications: There were strong and consistent associations between higher DII and cancer incidence and mortality across cancer types, study country, and study design. Clinical validation and use of this DII in the future can improve early identification and intervention of at-risk populations.