Higher Dietary Inflammatory Index scores are not associated with cognitive decline in the Framingham Heart Study

Abstract

AbstractBackgroundNutritional factors can abet or protect against systemic chronic inflammation, which plays an important role in the development and progression of dementia. We evaluated whether higher (i.e. pro‐inflammatory) Dietary Inflammatory Index(DII) scores were associated with accelerated cognitive decline in the community‐based Offspring Framingham Heart Study(FHS).Method889 older adults (mean age 59 years [standard deviation (SD)], 8;58.3% women]) completed validated 126‐item Food Frequency Questionnaires(FFQ), administered at FHS examination cycle 7 (1998‐2001) and examination cycle 5 (1991‐1995) and/or 6 (1995‐1998). We created a DII score (based on the published method by Shivappa et al. 2014); a cumulative DII score was calculated by averaging across a maximum of three FFQs. Cognitive testing was completed at examination cycles 7, 8 (2005‐2008) and 9 (2011‐2014). Exam 7 was considered as study baseline and participants were followed over a mean time of 13.4 years (SD 1.3). We excluded participants with prevalent dementia or stroke at baseline and those with no cognitive testing follow‐up data. We examined associations between the cumulative DII score and cognitive test scores over time using linear mixed models adjusting for age, age‐squared, sex, education, time from exam 7 to neuropsychological exam 7, and time (model1) and additionally for apolipoprotein e4, body mass index, total energy intake, total cholesterol: high‐density lipoprotein ratio, physical activity, smoking and anti‐cholesterol medication (model2).ResultHigher DII scores were significantly associated with accelerated decline in performance on the Trail Making Test B minus A(TMT‐B minus A) (processing speed and executive function), following adjustment for model 1 covariates (β±SE, ‐0.001± 0.0004,p = 0.03). but the association failed to reach significance in Model 2 (‐0.001±0.0003,p = 0.08). We observed no relationship between higher DII scores and other cognitive domains. Stratified analyses showed that higher DII scores were associated with accelerated decline in TMT‐B minus A scores among apolipoprotein e4 carriers (Model 2:‐0.002±0.001,p = 0.047) but not among non‐carriers (Model 2:‐0.0004±0.0004,p = 0.33).ConclusionHigher DII scores were not associated with cognitive decline. To date, such studies have been very limited, most studies that found a relationship, were cross‐sectional and have used less sensitive testing. Future studies are encouraged to examine whether our findings can be replicated.