Association Between the Dietary Inflammatory Index and Cognitive Frailty in Older Adults: A Cross Sectional Analysis...

Cognitive frailty (CF) is a prevalent geriatric syndrome associated with increased risks of falls, hospitalization, disability, and all-cause mortality among older adults. Emerging evidence suggests that chronic inflammation may contribute to the pathophysiology of CF, while dietary patterns can modulate inflammatory responses. The Dietary Inflammatory Index (DII) is a validated tool for quantifying the inflammatory potential of diet. Although higher DII scores have been associated with physical frailty and cognitive impairment, the association between DII and CF remains unclear.

To investigate the association between DII and CF in older adults.

We conducted a secondary analysis of cross-sectional data from the National Health and Nutrition Examination Survey (NHANES) 2011-2014 cycles, comprising 2,386 eligible participants. Participants were categorized into tertiles according to their DII scores: T1 (n = 709), T2 (n = 763), and T3 (n = 914). Survey-weighted logistic regression analyses were performed to examine the association between DII and CF. To examine potential nonlinear relationships, restricted cubic spline (RCS) regression was performed with three knots positioned at the 10th, 50th, and 90th percentiles of the DII distribution.

The prevalence of CF in the study sample was 14.9%, and the survey-weighted prevalence increased across DII tertiles, from 4.9% in the lowest tertile to 8.1% in the middle tertile and 16.6% in the highest tertile. Participants with CF had higher DII scores than those without CF (4.3 [IQR, 1.2 to 7.1] vs 1.5 [IQR, -2.3 to 4.7]). Participants with CF were also older and had higher white blood cell (WBC) counts and neutrophil-to-lymphocyte ratio (NLR) values than those without CF (all p < 0.05). In logistic regression analyses, each 1-unit increase in DII was associated with higher odds of CF in the the unadjusted model (OR 1.096, 95% CI 1.064-1.128), after sociodemographic adjustment (OR 1.056, 95% CI 1.026-1.088), and in the fully adjusted model (OR 1.039, 95% CI 1.001-1.080). Compared with participants in the lowest tertile, those in the highest tertile had higher odds of CF in both the unadjusted (OR 3.887, 95% CI 2.820-5.358) and fully adjusted (OR 2.254, 95% CI 1.522-3.337) analyses, whereas the association for the middle tertile was not statistically significant after full adjustment. RCS models indicated a nonlinear association (p for nonlinearity = 0.020), with the odds of CF increasing more steeply at DII values above approximately 2.4.

Higher DII scores were associated with higher odds of CF among older adults in the United States, with a steeper increase in the odds of CF at DII values above approximately 2.4. Prospective cohort studies and dietary trials are needed to establish temporality and determine whether reducing the inflammatory potential of diet can prevent the onset or progression of CF.