# Evaluating MRI correlates of lifestyle-based dementia risk reduction: Results from the AgeWell.de imaging study

## TL;DR

This study examined how lifestyle changes affect brain health markers in older adults at risk for dementia, finding limited evidence of structural brain changes linked to lifestyle improvements.

## Contribution

The study is one of the first to investigate MRI correlates of lifestyle-based dementia risk reduction in a longitudinal intervention trial.

## Key findings

- Lower dementia risk scores were associated with higher hippocampal volume at baseline.
- Improvements in lifestyle scores were not linked to changes in other neuroimaging markers.
- Detrimental lifestyle changes correlated with worse cognitive performance in the intervention group.

## Abstract

Multidomain lifestyle interventions can improve dementia risk by risk factor modification. Little is known about possible mechanisms underlying this effect.

Analyze whether changes in a validated dementia risk score were linked to changes in neuroimaging markers in a sample of older adults at increased dementia risk, participating in a multimodal lifestyle intervention.

Participants of the multi-centric AgeWell.de-trial at the Leipzig study site were examined using 3 Tesla MRI at baseline and 24-months follow-up, assessing markers of hippocampal-limbic atrophy and vascular pathology (hippocampal volume (HCV), entorhinal cortex thickness, free water fraction, peak width of skeletonized mean diffusivity, white matter hyperintensity volume, mean gray matter cerebral blood flow). Dementia risk was assessed using the Lifestyle for Brain Health (LIBRA)-index. Multivariable linear regression analyses assessed effects of changes in LIBRA on neuroimaging markers.

Of 56 participants at baseline, 41 underwent the follow-up assessment (Mage: 68.1 (4.1), % female: 46.3, intervention/control group: 16/25). Lower LIBRA-scores, indicating lower dementia risk, were associated with higher HCV at baseline. LIBRA improved in both groups, with no between-group difference in change. Increases in LIBRA were linked to smaller decline in HCV independently of the intervention. No further effects of lifestyle changes on neuroimaging were detected. Exploratory analyses indicated that detrimental lifestyle changes were linked to decreased cognitive performance in the intervention group.

We found no conclusive evidence for associations between lifestyle changes due to a multidomain lifestyle intervention and structural brain health markers. Larger samples and longer interventions may clarify underlying mechanisms.