Higher dietary inflammatory index scores are associated with increased incidence of all‐cause dementia in the Framingham Heart Study

Abstract

AbstractBackgroundNutrition is hypothesized to protect against systemic chronic inflammation, which plays an important role in the development and progression of disease including dementia. We evaluated whether higher (i.e. pro‐inflammatory) Dietary Inflammatory Index (DII) scores were associated with increased incidence of all‐cause dementia and Alzheimer’s disease (AD) in the community‐based Offspring Framingham Heart Study (FHS).Method1021 older adults (mean age 69 years [standard deviation (SD)], 5;52.3% women]) completed a validated 126‐item Food Frequency Questionnaire (FFQ). We created a DII score (based on the published method by Shivappa et al. 2014) based on previous studies linking individual dietary factors to six inflammatory markers (i.e. C‐reactive protein, interleukin (IL)‐1β , IL‐4, IL‐6, IL‐10 and tumor necrosis factor‐alpha, consisting of 31 components. A cumulative DII score was calculated by averaging across a maximum of three FFQs (administered at FHS exams 5 (1991‐1995), 6 (1995‐1998), and 7 (1998‐2001)). Exam 7 was considered as study baseline and participants were followed over a mean 12.6 years (SD 5.5). We excluded participants aged <60 years, those with prevalent dementia and/or other neurological conditions, and/or no dementia follow‐up.Result150 participants developed all‐cause dementia (including 118 participants who developed AD). Higher DII scores were associated with an increased incidence of all‐cause dementia following adjustment for age and sex (HR1.11,95%CI 1.01‐1.22,p=0.03). The relationship remained after additional adjustment for education, apolipoprotein e4, body mass index, smoking status, physical activity index score, total energy intake, lipid lowering medication and total cholesterol:high‐density lipoprotein‐ratio (HR1.14,95%CI 1.01‐1.29,p=0.04). We observed no relationship between higher DII scores and incident AD. Additionally, we observed no significant interactions between higher DII scores and sex, the presence of an APOE ε4 allele, or physical activity in their associations with incident all‐cause dementia or AD.ConclusionHigher DII scores were associated with a higher risk of incident all‐cause dementia, but not incident AD. Although these promising findings need to be replicated and further validated, our results suggest that diets which correlate with low DII scores could prevent late‐life dementia. Further, future studies are encouraged to test our findings among older adults of other race and ethnic groups and over a longer follow‐up period.