Construct validation of the Dietary Inflammatory Index among African Americans

OBJECTIVE: Chronic inflammation is linked to many chronic conditions. One of the strongest modulators of chronic inflammation is diet. The Dietary Inflammatory Index (DII) measures dietary inflammatory potential and has been validated previously, but not among African Americans (AAs). DESIGN: Cross-sectional analysis using baseline data from the Healthy Eating and Active Living in the Spirit (HEALS) intervention study. SETTING: Baseline data collection occurred between 2009 and 2012 in or near Columbia, SC. PARTICIPANTS: African-American churchgoers. MEASUREMENTS: Baseline data collection included c-reactive protein (CRP) and interleukin-6 from blood draws, anthropometric measures, and numerous questionnaires. The questionnaires included a food frequency questionnaire which was used for DII calculation. The main analyses were performed using quantile regression. RESULTS: Subjects in the highest DII quartile (i.e., more pro-inflammatory) were younger, more likely to be married, and had less education and greater BMI. Individuals in DII quartile 4 had statistically significantly greater CRP at the 75th and 90th percentiles of CRP versus those in quartile 1 (i.e., more anti-inflammatory). CONCLUSION: Construct validation provides support for using the DII in research among AA populations. Future research should explore avenues to promote more anti-inflammatory diets, with use of the DII, among AA populations to reduce risk of chronic disease.