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

Background Multidomain lifestyle interventions can improve dementia risk by risk factor modification. Little is known about possible mechanisms underlying this effect. Objective 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. Methods 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. Results Of 56 participants at baseline, 41 underwent the follow-up assessment (M age : 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. Conclusions 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.