Dietary Inflammatory Index and Risk of Major Digestive Tract Cancers - A GRADE-Assessed Systematic Review and Dose-Response Meta-Analysis

Sep 22, 2026

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Gastrointestinal (GI) cancers represent a broad set of malignant tumors affecting the digestive system. This GRADE-assessed systematic review and dose-response meta-analysis evaluates the association between the Dietary Inflammatory Index (DII) and the risk of GI cancers by synthesizing evidence from observational studies. Searches in PubMed, Scopus, and Web of Science identified 52 studies, including cohort and case-control designs. Higher DII scores were linked with increased colorectal, colon, and rectal cancer risks in cohort data, while case-control findings showed stronger associations for oral, esophageal, and pancreatic cancers. The study also applies formal risk-of-bias assessment and grades evidence certainty using the GRADE framework.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages19

Reading Time48 min

AccessFree to download

Abstract

Introduction

Background and burden of GI cancers

Modifiable risk factors and dietary patterns

Inflammation and diet as potential mechanisms

Methods

Literature search strategy

Study selection and outcomes

Meta-analysis approach and quality assessment

Results

Associations in cohort studies

Associations in case-control studies

Conclusion

Bakhshimoghaddam etal. BMC Cancer (2026) 26:417 BMC Cancer [https://doi.org/10.1186/s12885-026-15677-0](https://doi.org/10.1186/s12885-026-15677-0) SYSTEMATIC REVIEW Open Access Dietary inflammatory index and risk of major digestive tract cancers: a GRADE-assessed systematic review and dose-response metaanalysis Farnush Bakhshimoghaddam1,2,3, Rezvan Chaharlang4, Maryam Shirani5, Mohammad Ghamari6 and Sedighe Rastaghi7* Abstract Background & aims Gastrointestinal (GI) cancers are an umbrella term for a group of malignant tumors that affect the digestive system. This systematic review and meta-analysis aimed to evaluate the association between the Dietary Inflammatory Index (DII) and the risk of GI cancers by synthesizing evidence from observational studies. Methods PubMed, Scopus, and Web of Science were searched using terms related to GI cancers and DII. A total of 52 observational studies (18 cohort, 34 case-control) were analyzed. Random or fixed effects meta-analyses were conducted to pool risk ratio (RR) for the highest vs. the lowest DII categories, with dose-response analyses performed where feasible. Quality was assessed via the Risk of Bias in Non-randomised Studies of Exposures tool. Evidence certainty was graded using the GRADE framework. Results Higher DII scores (pro-inflammatory diets) were significantly associated with increased risks of colorectal (RR 1. 16, 95% confidence interval [CI] 1.04–1. 29), colon (RR 1. 12, 95% CI 1.11–1. 33), and rectal cancers (RR 1. 25, 95% CI 1.07–1.47) in cohort studies. No significant associations were found for gastric or pancreatic cancers in cohort studies. Case-control studies showed stronger associations for oral (RR 2 .46), esophageal (RR 2 . 63), and pancreatic cancers (RR 2. 57) . Conclusion The findings highlight the importance of dietary modifications to reduce inflammation for cancer prevention. Further prospective studies are needed to clarify causal relationships and refine dietary recommendations. Systematic review registration PROSPERO registration no. CRD42023484691 . Keywords Inflammation, Dietary inflammatory index, Gastrointestinal cancer, Meta-analysis *Correspondence: Sedighe Rastaghi [sedigherastaghi@gmail.com](sedigherastaghi@gmail.com) 1Student Research Committee, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran 2Nutrition and Metabolic Diseases Research Center, Clinical Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran 3Department of Nutrition, School of Allied Medical Sciences, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran 4Student Research Committee, Department of Clinical Nutrition and Dietetics, Faculty of Nutrition Sciences and Food Technology, National Nutrition and Food Technology Research Institute, Shahid Beheshti University of Medical Sciences, Tehran, Iran 5Toxicology Research Center, Medical Basic Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran 6Student Research Committee, Dezful University of Medical Sciences, Dezful, Iran 7Department of Acupuncture, School of Persian and Complementary Medicine, Mashhad University of Medical Sciences, Mashhad, Iran © The Author(s) 2026. Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the ar

FAQs

What was the goal of the study regarding the Dietary Inflammatory Index (DII)?

To evaluate the association between the DII and the risk of gastrointestinal (GI) cancers by synthesizing evidence from observational studies.

How many observational studies were included, and what types were analyzed?

A total of 52 observational studies were analyzed, including 18 cohort studies and 34 case-control studies.

Which GI cancer sites showed significant associations with higher DII scores in cohort studies?

Higher DII scores were significantly associated with increased risks of colorectal, colon, and rectal cancers in cohort studies.

What did the authors conclude about dietary changes and future research needs?

The findings emphasize dietary modifications to reduce inflammation for cancer prevention, and the authors call for further prospective studies to clarify causality and refine dietary recommendations.

Sep 22, 2026

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