Association of mild and complex multimorbidity with structural brain changes in older adults: A population-based study.

INTRODUCTION

We quantified the association of mild (ie, involving one or two body systems) and complex (ie, involving ≥3 systems) multimorbidity with structural brain changes in older adults.

METHODS

We included 390 dementia-free participants aged 60+ from the Swedish National Study on Aging and Care in Kungsholmen who underwent brain magnetic resonance imaging at baseline and after 3 and/or 6 years. Using linear mixed models, we estimated the association between multimorbidity and changes in total brain tissue, ventricular, hippocampal, and white matter hyperintensities volumes.

RESULTS

Compared to non-multimorbid participants, those with complex multimorbidity showed the steepest reduction in total brain (βtime -0.03, 95% CI -0.05, -0.01) and hippocampal (βtime -0.05, 95% CI -0.08, -0.03) volumes, the greatest ventricular enlargement (βtime 0.03, 95% CI 0.01, 0.05), and the fastest white matter hyperintensities accumulation (βtime 0.04, 95% CI 0.01, 0.07).

DISCUSSION

Multimorbidity, particularly when involving multiple body systems, is associated with accelerated structural brain changes, involving both neurodegeneration and vascular pathology.

HIGHLIGHTS

Multimorbidity accelerates structural brain changes in cognitively intact older adults These brain changes encompass both neurodegeneration and cerebrovascular pathology The complexity of multimorbidity is associated with the rate of brain changes' progression.