# Associations of Dietary Decanoic Acid Intake With Cognitive Function in the Elderly and the Mediating Effects of Hypertension and Diabetes: An Analysis From NHANES 2011–2014

## TL;DR

Higher dietary decanoic acid intake is linked to better cognitive function in older adults, with hypertension and diabetes partially explaining this relationship.

## Contribution

This study identifies a positive association between decanoic acid intake and cognitive function in the elderly, with mediation by hypertension and diabetes.

## Key findings

- DDA intake was positively associated with comprehensive cognitive function (β = 0.539, p = 0.007).
- Hypertension and diabetes mediated 27.53% and 24.33% of the total effect, respectively.
- The association remained consistent across subgroups, with no significant interactions.

## Abstract

Cognitive decline among the elderly is an increasingly prominent issue amid global population aging. Decanoic acid has been hypothesized to be associated with cognitive function. However, the relationship of decanoic acid with cognitive function in the elderly remains unclear.

This study analyzed the participants aged 60 years and older from National Health and Nutrition Examination Survey (NHANES) 2011–2014. Dietary decanoic acid (DDA) intake was derived from two 24‐h dietary recalls. Cognitive function was assessed via immediate recall test (IRT), delayed recall test (DRT), animal fluency test (AFT), and digit symbol substitution test (DSST). Higher scores on these tests indicated better cognitive performance. Weighted multivariate linear regression, restricted cubic spline (RCS) curves, subgroup analyses, and mediating analysis were used to explore the relationship between DDA intake and cognitive function.

A total of 2246 older adults were included in this study. After adjusting for confounding variables, DDA intake was positively associated with comprehensive cognitive function (β = 0.539, 95% CI: 0.168–0.910, p = 0.007). The RCS curve shows a positive correlation between DDA intake and comprehensive cognitive function (p‐value for overall < 0.001, p‐value for nonlinearity = 0.050). Subgroup analyses showed that the association remained relatively consistent across subgroups (all p for interaction > 0.05). Mediating analysis revealed that the indirect effects of hypertension and diabetes accounted for 27.53% and 24.33% of the total effect, respectively.

DDA intake is positively associated with global cognitive function in older adults. Hypertension and diabetes may partially mediate this relationship. The cross‐sectional study design limits causal inference, and prospective or interventional studies should be conducted in the future.

This study included elderly people aged 60 and above in the NHANES 2011–2014 cycle. The research indicated that increased dietary decanoic acid intake was associated with better cognitive function in the elderly, among which diabetes and hypertension were statistically associated with a partial mediating effect, although causality cannot be inferred.