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Associations Between Cerebral Microbleed Patterns and Incident Dementia: The ARIC-Neurocognitive Study
Richard Q Vuong1, Valerie N Morrill1, Jonathan Graff-Radford2
1Stroke Branch, National Institute of Neurological Disorders and Stroke Intramural Research Program, National Institutes of Health, Bethesda, MD (R.Q.V., V.N.M., R.F.G.).
Stroke
|February 27, 2026
Summary
Cerebral microbleeds (CMBs) in lobar or mixed patterns, and higher CMB counts, increase dementia risk. Subcortical CMBs alone did not show this association, indicating pattern-specific risks.
Area of Science:
- Neuroimaging
- Neurology
- Epidemiology
Background:
- Cerebral microbleeds (CMBs) are linked to dementia, but the impact of specific patterns, like lobar (often from cerebral amyloid angiopathy) versus subcortical (often hypertensive), requires clarification.
- Cortical superficial siderosis (cSS) can co-occur with lobar CMBs, potentially influencing dementia risk.
- Understanding distinct CMB patterns is crucial for assessing dementia risk accurately.
Purpose of the Study:
- To investigate the association between the presence, patterns, and frequency of cerebral microbleeds (CMBs) and the risk of developing dementia.
- To differentiate the dementia risk associated with various CMB patterns, including lobar, subcortical, mixed, and those with cSS.
- To determine if the number of CMBs correlates with dementia risk across different subtypes.
Main Methods:
- Analysis of a community-based longitudinal cohort (ARIC-NCS) using 3T MRI at visit 5.
- Classification of CMB patterns: no CMBs, subcortical only, mixed (subcortical and lobar±cSS), lobar±cSS only, or cSS.
- Dementia adjudication via blinded review; Cox proportional hazards models used to assess dementia risk associations, adjusted for covariates.
Main Results:
- Among 1583 participants, 361 had CMBs. Mixed (HR, 1.99) and lobar±cSS (HR, 1.96) CMB patterns were associated with increased dementia risk compared to no CMBs.
- Subcortical-only CMB patterns did not show a significant association with increased dementia risk (HR, 1.04).
- Presence of cSS (HR, 2.57) and increasing numbers of CMBs across all subtypes were associated with higher dementia risk.
Conclusions:
- Lobar and mixed cerebral microbleed (CMB) patterns, along with a higher CMB burden, are significantly associated with incident dementia.
- The study highlights differential associations of specific CMB patterns with dementia risk.
- A substantial disease burden, irrespective of CMB distribution, is linked to an elevated risk of dementia.
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