Longitudinal changes in the dietary inflammatory index: an assessment of the inflammatory potential of diet over time in the Women’s Health Initiative (1034.5)

The role of diet in modifying chronic disease risk through its potential effect on inflammation is of great interest. We assessed changes over time in the inflammatory potential of specific dietary factors in the Observational Study cohort of the Women’s Health Initiative using the dietary inflammatory index (DII).The DII was calculated based on data from two food frequency questionnaires self reported at baseline and year 3 (n=77,437). A more negative DII score represents a more anti‐inflammatory diet. Linear mixed models were used to calculate multivariable‐adjusted mean changes in DII over time. At baseline and year 3, the mean DII was ‐0.98 and ‐1.33, respectively, with a Pearson correlation coefficient of 0.60. The mean inflammatory potential of diet decreased over the 3‐year period, and varied among categories of age, BMI, and special diet status (any of low‐calorie, low‐fat/cholesterol, low‐sodium or high‐fiber diets; all p<0.0001): the average decrease in DII scores after 3 years was ‐0.44, ‐0.37, and ‐0.29 in normal weight, overweight, and obese women, respectively, while women who reported being on a special diet had a smaller decrease (‐0.29) than women who were not on special diets (‐0.43). Improvements in diet quality based on decreases in the inflammatory potential of self‐reported diet were observed. Future studies should evaluate change in diet quality and its association with chronic disease risk. Grant Funding Source : The WHI was funded by the NHLB; Dr. Hebert and Mr.Tabung by NCI grants K05CA136975 & 1F31CA177255