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The following is a summary of “Cluster-Based White Matter Signatures and the Risk of Dementia, Stroke, and Mortality in Community-Dwelling Adults,” published in the September 2024 issue of Neurology by Rosbergen et al.

Brain MRI scans can reveal various white matter (WM) abnormalities that may indicate underlying health issues, but extensive research on these patterns is needed.

Researchers conducted a retrospective study identifying different WM patterns on brain MRIs, associated risk factors, and potential links to dementia, stroke, and mortality.

They measured WM hyperintensities (WMHs) volume, WM volume, fractional anisotropy (FA), and mean diffusivity (MD) via automated pipelines on structural and diffusion MRI in Rotterdam study participants over 45 years old (2005 to 2016). Hierarchical clustering identified distinct white matter injury clusters, with Cox models revealing their differential risks for dementia, stroke, and mortality.

The results showed 5,279 participants (mean age 65.0 years, 56.0% women), 4 WM signatures were identified, high microstructural integrity with minimal WM atrophy and WMH, high microstructural integrity with minimal WMH but significant WM atrophy, poor microstructural integrity with substantial WMH and minimal WM atrophy, and poor microstructural integrity with significant WMH and WM atrophy. Clusters 3 and 4 had a higher prevalence of cardiovascular risk factors, lacunes, and cerebral microbleeds than clusters 1 and 2. Over a median follow-up of 10.7 years, 291 participants developed dementia, 220 had a stroke, and 910 died. Dementia risk was higher for all clusters compared to cluster 1, with the highest risk in cluster 3 (HR 3.06, 95% CI 2.12–4.42), followed by cluster 4 (HR 2.31, 95% CI 1.58–3.37) and cluster 2 (HR 1.67, 95% CI 1.17–2.38). Stroke risk was elevated only in clusters 3 (HR 1.55, 95% CI 1.02–2.37) and 4 (HR 1.94, 95% CI 1.30–2.89). Mortality risk increased across all clusters compared to cluster 1 (cluster 2: HR 1.27, 95% CI 1.06–1.53; cluster 3: HR 1.65, 95% CI 1.35–2.03; cluster 4: HR 1.76, 95% CI 1.44–2.15). Clusters showed better goodness of fit for dementia and mortality but not for stroke, compared to individual imaging markers.

Investigators found that grouping WM abnormalities can identify unique patterns linked to different health risks, and future studies should focus on the location of these abnormalities.

Source: neurology.org/doi/10.1212/WNL.0000000000209864