# Socioeconomic status modifies the association between adherence to the Mediterranean diet and cognitive outcomes: results from the Collaborative PROMED-COG Pooled Cohorts Study

## TL;DR

This study finds that the benefits of a Mediterranean diet on cognitive decline depend on a person's socioeconomic status, with greater effects seen in wealthier individuals.

## Contribution

The study reveals that socioeconomic status modifies the cognitive benefits of Mediterranean diet adherence, particularly in high-SES groups.

## Key findings

- Higher Mediterranean diet adherence was linked to reduced cognitive decline risk in high socioeconomic status individuals.
- Medium physical activity adherence further reduced cognitive decline risk in high socioeconomic status groups.
- No significant association was found between diet/activity adherence and dementia incidence across all socioeconomic levels.

## Abstract

This study examines whether adherence to the Mediterranean diet (MD), alone and combined with physical activity (MedEx), is associated with cognitive decline and dementia incidence, with socioeconomic status (SES) as a potential modifier.

We included 8,568 subjects (mean age 72.3 ± 9.6 years, 52.4% female) from three pooled Italian population-based studies. MD adherence was assessed using the Panagiotakos algorithm. We analyzed the association of MD and MedEx adherence, both continuously and categorized in tertiles, with cognitive decline and incident dementia using Cox regression. SES modification was examined through interaction analysis and SES-stratified models.

Cognitive decline occurred in 38.1% of participants but was not associated with MD adherence. In SES-stratified analysis, among high SES individuals, each 2-point increase in MD adherence reduced cognitive decline risk by 14%, and high MD adherence was associated with a 48% reduction (HR 0.52, 95%CI 0.31–0.90). In this group, medium MedEx adherence reduced cognitive decline risk by 77% (HR 0.23, 95%CI 0.07–0.83). No significant association was found between MD/MedEx adherence and incident dementia (4.2%), regardless of SES.

SES may modify the relationship between MD and cognitive decline, with greater benefits observed in higher SES groups. Further studies, particularly in vulnerable populations, are needed to inform tailored preventive strategies for cognitive decline.

The online version contains supplementary material available at 10.1007/s00127-025-02993-2.