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

Wolfgang Marx; Nicola Veronese; Jaimon T Kelly; Lee Smith; Meghan Hockey; Sam Collins; Gina L Trakman; Erin Hoare; Scott B Teasdale; Alexandra Wade; Melissa Lane; Hajara Aslam; Jessica A Davis; Adrienne O'Neil; Nitin Shivappa; James R Hebert; Lauren C Blekkenhorst; Michael Berk; Toby Segasby; Felice Jacka

doi:10.1093/advances/nmab037

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

Adv Nutr. 2021 Oct 1;12(5):1681-1690. doi: 10.1093/advances/nmab037.

Authors

Wolfgang Marx¹, Nicola Veronese², Jaimon T Kelly^{3

4}, Lee Smith⁵, Meghan Hockey¹, Sam Collins¹, Gina L Trakman⁶, Erin Hoare¹, Scott B Teasdale⁷, Alexandra Wade⁸, Melissa Lane¹, Hajara Aslam¹, Jessica A Davis¹, Adrienne O'Neil^{1

9}, Nitin Shivappa^{10

11}, James R Hebert^{10

11}, Lauren C Blekkenhorst^{12

13}, Michael Berk¹, Toby Segasby¹, Felice Jacka^{1

14

15

16}

Affiliations

¹ Deakin University, Institute for Mental and Physical Health and Clinical Translation (IMPACT), Food & Mood Centre, School of Medicine, Barwon Health, Geelong, Victoria, Australia.
² University of Palermo, Department of Internal Medicine, Geriatrics Section, Palermo, Italy.
³ Centre of Applied Health Economics, Griffith University, Brisbane, Queensland, Australia.
⁴ Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia.
⁵ The Cambridge Centre for Sport and Exercise Sciences, Anglia Ruskin University, Cambridge, UK.
⁶ Department of Dietetics, Nutrition, and Sport, La Trobe University, Melbourne, Victoria, Australia.
⁷ School of Psychiatry, UNSW Sydney, Sydney, New South Wales, Australia.
⁸ Alliance for Research in Exercise, Nutrition, and Activity, Allied Health and Human Performance, University of South Australia, Adelaide, South Australia, Australia.
⁹ Melbourne School of Population & Global Health, University of Melbourne, Melbourne, Victoria, Australia.
¹⁰ Department of Epidemiology and Biostatistics and Cancer Prevention and Control Program, Arnold School of Public Health, University of South Carolina, Columbia, South Carolina, USA.
¹¹ Department of Nutrition, Connecting Health Innovations LLC, Columbia, South Carolina, USA.
¹² School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.
¹³ Medical School, The University of Western Australia, Perth, Western Australia, Australia.
¹⁴ Black Dog Institute, Sydney, New South Wales, Australia.
¹⁵ James Cook University, Townsville, Queensland, Australia.
¹⁶ Centre for Adolescent Health, Murdoch Children's Research Institute, VIC, Australia.

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

Publication types

Research Support, Non-U.S. Gov't
Systematic Review

MeSH terms

Diet*
Humans
Meta-Analysis as Topic
Neoplasms*
Observational Studies as Topic