Elsevier

Advances in Nutrition

Volume 12, Issue 5, September 2021, Pages 1681-1690
Advances in Nutrition

The Dietary Inflammatory Index and Human Health: An Umbrella Review of Meta-Analyses of Observational Studies

https://doi.org/10.1093/advances/nmab037Get rights and content
Under an Elsevier user license
open archive

ABSTRACT

Numerous observational studies have investigated the role of the Dietary Inflammatory Index (DII®) in chronic disease risk. The aims of this umbrella review and integrated meta-analyses were to systematically synthesize the observational evidence reporting on the associations between the DII and health outcomes based on meta-analyses, and to assess the quality and strength of the evidence for each associated outcome. This umbrella review with integrated meta-analyses investigated the association between the DII and a range of health outcomes based on meta-analyses of observational data. A credibility assessment was conducted for each outcome using the following criteria: statistical heterogeneity, 95% prediction intervals, evidence for small-study effect and/or excess significance bias, as well as effect sizes and P values using calculated random effects meta-analyses. In total, 15 meta-analyses reporting on 38 chronic disease-related outcomes were included, incorporating a total population of 4,360,111 subjects. Outcomes (n = 38) were examined through various study designs including case-control (n = 8), cross-sectional (n = 5), prospective (n = 5), and combination (n = 20) study designs. Adherence to a pro-inflammatory dietary pattern had a significant positive association with 27 (71%) of the included health outcomes (P value < 0.05). Using the credibility assessment, Class I (Convincing) evidence was identified for myocardial infarction only, Class II (Highly suggestive) evidence was identified for increased risk of all-cause mortality, overall risk of incident cancer, and risk of incident site-specific cancers (colorectal, pancreatic, respiratory, and oral cancers) with increasing (more pro-inflammatory) DII score. Most outcomes (n = 31) presented Class III (Suggestive) or lower evidence (Weak or No association). Pro-inflammatory dietary patterns were nominally associated with an increased risk of many chronic disease outcomes. However, the strength of evidence for most outcomes was limited. Further prospective studies are required to improve the precision of the effect size.

Keywords

diet
inflammation
dietary inflammatory index
prevention
mental disorders
cancer
cardiovascular disease
non-communicable disorders
medicine

Cited by (0)

WM is currently funded by an Alfred Deakin Postdoctoral Research Fellowship and a Multiple Sclerosis Research Australia Early Career Fellowship. WM has previously received funding from the Cancer Council Queensland and university grants/fellowships from La Trobe University, Deakin University, University of Queensland, and Bond University; received industry funding and has attended events funded by Cobram Estate Pty. Ltd; received travel funding from theNutrition Society of Australia; received consultancy funding from Nutrition Research Australia; and has received speakers'  honoraria from The Cancer Council Queensland and the Princess Alexandra Research Foundation. JK is supported through a Griffith University Postdoctoral Research Fellowship. MB is supported by a NHMRC Senior Principal Research Fellowship (1156072). MB has received grant/research support from the NIH, Cooperative Research Centre, Simons Autism Foundation, Cancer Council of Victoria, Stanley Medical Research Foundation, Medical Benefits Fund, National Health and Medical Research Council, Medical Research Futures Fund, Beyond Blue, Rotary Health, A2 Milk Company, Meat and Livestock Board, Woolworths, Avant, and the Harry Windsor Foundation; has been a speaker for Astra Zeneca, Lundbeck, Merck, Pfizer; and served as a consultant to Allergan, Astra Zeneca, Bioadvantex, Bionomics, Collaborative Medicinal Development, Lundbeck Merck, Pfizer and Servier—all unrelated to this work. EH is supported by a National Health and Medical Research Council Early Career Fellowship (APP1156909). MH is supported by an Australian Rotary Health PhD Scholarship and has received research support from the A2 Milk Company. SC is supported by a Deakin University Postgraduate Research (DUPR) Scholarship. ST is funded through the Mindgardens Alliance and is a contractor to Nutrition Research Australia. HA is supported by a Deakin University Postgraduate Industry Research Scholarship. AO is supported by a Future Leader Fellowship (#101160) from the Heart Foundation Australia and Wilson Foundation. AO has received research funding from the National Health & Medical Research Council, Australian Research Council, University of Melbourne, Deakin University, Sanofi, Meat and Livestock Australia, and Woolworths Limited; and honoraria from Novartis. The Food & Mood Centre has received funding from the Fernwood Foundation, the A2 Milk Company, and Be Fit Foods. AW is supported by an NHMRC Boosting Dementia Research Grant (GNT1171313). AW has received previous funding from the University of South Australia, the Nutrition Society of Australia, and the Pork Cooperative Research Centre, all of which are unrelated to this work. FJ has received: 1) competitive grant/research support from the Brain and Behaviour Research Institute, the National Health and Medical Research Council (NHMRC), Australian Rotary Health, the Geelong Medical Research Foundation, the Ian Potter Foundation, The University of Melbourne; 2) industry support for research from Meat and Livestock Australia, Woolworths Limited, the A2 Milk Company, Be Fit Foods; 3) philanthropic support from the Fernwood Foundation, Wilson Foundation, the JTM Foundation, the Serp Hills Foundation, the Roberts Family Foundation, the Waterloo Foundation; and 4) travel support and speakers'  honoraria from Sanofi-Synthelabo, Janssen Cilag, Servier, Pfizer, Health Ed, Network Nutrition, Angelini Farmaceutica, Eli Lilly, and Metagenics. FJ has written 2 books for commercial publication. ML is supported by a Deakin University Scholarship and has received research funding support from Be Fit Foods. LCB is supported by an NHMRC of Australia Emerging Leadership Investigator Grant (ID: 1172987) and a National Heart Foundation of Australia Post-Doctoral Research Fellowship (ID: 102498). LCB has received project funding from Edith Cowan University and the Department of Health Western Australia; and travel support from the Nutrition Society of Australia and The University of Western Australia.

Author disclosures: Dr James R. Hébert owns a controlling interest in Connecting Health Innovations LLC (CHI), a company that has licensed the right to his invention of the dietary inflammatory index (DII®) from the University of South Carolina in order to develop computer and smart phone applications for patient counselling and dietary intervention in clinical settings. Dr Nitin Shivappa is an employee of CHI. The subject matter of this paper will not have any direct bearing on that work, nor has that activity exerted any influence on this project.