Designing and developing a literature-derived, population-based dietary inflammatory index.
OBJECTIVE
To design and develop a literature-derived, population-based dietary inflammatory index (DII) to compare diverse populations on the inflammatory potential of their diets.


METHODS
Peer-reviewed primary research articles published through December 2010 on the effect of diet on inflammation were screened for possible inclusion in the DII scoring algorithm. Qualifying articles were scored according to whether each dietary parameter increased (+1), decreased (-1) or had no (0) effect on six inflammatory biomarkers: IL-1β, IL-4, IL-6, IL-10, TNF-α and C-reactive protein.


METHODS
The Dietary Inflammatory Index Development Study was conducted in the Cancer Prevention and Control Program of the University of South Carolina in Columbia, SC, USA from 2011 to 2012.


RESULTS
A total of ≈6500 articles published through December 2010 on the effect of dietary parameters on the six inflammatory markers were screened for inclusion in the DII scoring algorithm. Eleven food consumption data sets from countries around the world were identified that allowed individuals' intakes to be expressed relative to the range of intakes of the forty-five food parameters observed across these diverse populations. Qualifying articles (n 1943) were read and scored based on the forty-five pro- and anti-inflammatory food parameters identified in the search. When fit to this composite global database, the DII score of the maximally pro-inflammatory diet was +7·98, the maximally anti-inflammatory DII score was -8·87 and the median was +0·23.


CONCLUSIONS
The DII reflects both a robust literature base and standardization of individual intakes to global referent values. The success of this first-of-a-kind attempt at relating intakes of inflammation-modulating foods relative to global norms sets the stage for use of the DII in a wide variety of epidemiological and clinical studies.
1Cancer Prevention and Control Program,University of South Carolina,915 Greene Street,Suite 241,Columbia,SC 29208,USA.
Nitin
N
Shivappa
1Cancer Prevention and Control Program,University of South Carolina,915 Greene Street,Suite 241,Columbia,SC 29208,USA.
Susan E
SE
Steck
1Cancer Prevention and Control Program,University of South Carolina,915 Greene Street,Suite 241,Columbia,SC 29208,USA.
Thomas G
TG
Hurley
2Department of Epidemiology and Biostatistics,Arnold School of Public Health,University of South Carolina,Columbia,SC,USA.
James R
JR
Hussey
1Cancer Prevention and Control Program,University of South Carolina,915 Greene Street,Suite 241,Columbia,SC 29208,USA.
James R
JR
Hébert
D000465:Algorithms; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism*; D004032:Diet / Q000009:adverse effects*; D005247:Feeding Behavior; D006801:Humans; D007249:Inflammation / Q000097:blood / Q000209:etiology*; D018836:Inflammation Mediators / Q000097:blood*; D007378:Interleukins / Q000097:blood*; D015596:Nutrition Assessment; D009752:Nutritional Status; D014409:Tumor Necrosis Factor-alpha / Q000097:blood*
D015415:Biomarkers; D018836:Inflammation Mediators; D007378:Interleukins; D014409:Tumor Necrosis Factor-alpha; D002097:C-Reactive Protein