Secular trends in Dietary Inflammatory Index among adults in the United States, 1999–2014

Objective: The objective of this study was to evaluate secular trends in Dietary Inflammatory Index (DII) scores in the United States between 1999 and 2014. Methods: Data from adults over 19 years from the 1999 to 2014 National Health and Nutrition Examination Survey (N = 39,191) were used. DII scores, at each 2-year cycle, were evaluated from a 24-h recall, including 26 food parameters for DII calculation. Analyses were conducted in 2018. Results: For the entire sample, there was a quadratic trend (Ptrend < 0.001), with the DII scores peaking in 2003–2004, and then decreasing during the cycles from 2005 to 2014. Similar quadratic trends (Ptrend < 0.001) were observed by age, gender, race-ethnicity, and education. Conclusion: Males, non-Hispanic Blacks, younger adults, and those with less education adults had the highest DII scores (i.e., indicating the greatest inflammatory potential). The overall DII scores of the US population showed a quadratic trend from 1999 to 2014. Continued monitoring of DII changes is needed to better understand changes in the inflammatory potential of diet of American adults, and how they relate to changes in the risk of chronic disease. © 2018, Springer Nature Limited.