(P14-017-23) Relationship Between Non-Energy and Energy-Adjusted Dietary Inflammatory Index and Healthy Eating Index: Analysis of the National Health and Nutrition Examination Survey

Objectives: Acknowledging the relationship between diet and systemic inflammation, the Dietary Inflammatory Index (DII^®) was developed to categorize diet from pro- to anti-inflammatory. The Energy-Adjusted DII^® (E-DII^TM) does the same but on a 1,000-kilocalorie basis. The Healthy Eating Index (HEI) measures dietary quality by assessing diet against the Dietary Guidelines for Americans, yet scoring is also on a density basis of 1,000 kilocalories. The purpose of this study was to evaluate differences in the relationship between HEI and DII^® and HEI and E-DII^TM.

Methods: Analysis included 5,289 adults participating in NHANES between 2015-2018. DII^® and E-DII^TM scores were calculated and converted to quartiles. Linear regression was used to estimate the association between DII^® and E-DII^TM quartiles with HEI. Separate models were used to examine DII^® and E-DII^TM. Unadjusted models were used to assess HEI with DII^® and E-DII^TM whereas adjusted models included gender, race, education, age, body mass index, and family income-to-poverty ratios. Bootstrap methods were used to estimate the difference between coefficients for E-DII^TM and DII^® from their respective models.

Results: Results suggest that HEI scores were significantly lower moving across DII^® and E-DIITM quartiles in unadjusted models (p < 0.001). Similar results were observed in adjusted models (p < 0.001). The r2 value remained similar (52%) in unadjusted and adjusted E-DII^TM models, whereas the r² value increased from 17% in the unadjusted model to 26% in the adjusted DII^® model. The difference between HEI scores for the first versus the fourth quartile of DII^® scores was significantly larger than the difference between HEI scores for the first versus the fourth quartile of E-DII^TM scores (bootstrap estimated 95% CI 53.41, 62.41).

Conclusions: Significant associations were observed HEI, DII^®, and E-DII^TM scores across sociodemographic characteristics. R² values suggest that the E-DII^TM explained more variation in HEI compared to DII^®. An inflammatory index along with the HEI provides further understanding into relationships between dietary quality by nutrient and food group on inflammation and inflammatory-related chronic diseases.

Funding Sources: The authors have no funding sources to disclose for this research.