Higher Dietary Inflammatory Index scores are associated with higher beta‐amyloid deposition in the Framingham Heart Study

Abstract

AbstractBackgroundHigh Inflammatory content of diet enhances systemic chronic inflammation, a pathway which plays an important role in the development and progression of dementia. We investigated the cross‐sectional relationships between long‐term Dietary Inflammatory Index (DII) scores and beta‐amyloid(Aβ) and tau Positron Emission Tomography(PET) among participants of the community‐based Framingham Heart Study(FHS).Method343 adults (mean age 58 years [standard deviation (SD)], 10; 51% 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 34 components. A cumulative DII score was calculated by averaging across two FFQs (administered at FHS Generation 2(GEN2) examination cycles 8(2005‐2008) and 9(2011‐2014), and at Generation 3(GEN3) examination cycles 2 (2008‐2011) and 3 (2016‐2019). Cumulative DII scores were examined as a continuous variable and using median‐split(‐1.11). Aβ and tau PET examinations were conducted(2016‐2021) using synthesized 11C‐Pittsburgh compound B(PiB) and/or F‐18‐flortaucipir(FTP) tracers. Examination cycles 9(GEN2) and 3(GEN3) were considered as study baseline. We used linear regression to relate the cumulative DII score to Aβ (Fronto‐lateral‐retrosplenial uptake(FLR) and precuneus) and tau (entorhinal, inferior temporal, rhinal, cortical composite and global composite) PET regions.ResultHigher cumulative DII scores, as compared to DII scores below the median, were associated with higher amyloid precuneus region (β±SE, 0.023±0.011,p = 0.042) after adjustment for age, age‐squared, sex, camera and time between DII exam and PET scan exam. No other relationships were observed between DII and Aβ and tau PET. Interaction analyses showed interactions between DII (median‐split) and age (median‐split 58y) when testing association between median‐split DII and Aβ regions and tau global composite region. Stratified analyses showed relationships between higher DII vs. below median DII and higher amyloid FLR and precuneus region (0.055 ± 0.055,p = 0.037; 0.050±0.022,p = 0.022,respectively) among individuals aged 58y>, but not among individuals <58y (‐0.004±0.006,p = 0.947;0.000±0.000,p = 0.999,respectively). There were no significant interactions by sex and apolipoproteinE4 status in the association between DII and Aβ and tau PET.ConclusionHigher DII scores were associated with increased Aβ deposition.