„Veränderungen der weißen Substanz“ im MRT-Befund: Was sie für das Gedächtnis bedeuten – und was nicht

<h4>Background and objectives</h4>Cerebral "dirty-appearing" or "diffusely abnormal" white matter (DAWM) represents subtle white matter abnormalities that are associated with progression of cerebral small vessel disease (cSVD), but the association with cognitive function and dementia is unclear. Our aim was to study the association between DAWM and cognitive function, long-term cognitive decline, and long-term dementia risk in community-dwelling older adults with limited baseline cSVD burden.<h4>Methods</h4>Participants of the prospective Age-Gene/Environment Susceptibility-Reykjavik longitudinal cohort study underwent 1.5T brain MRI scans. DAWM was visually rated on baseline fluid-attenuated inversion recovery (FLAIR) MRI as a percentage of lobar white matter volume (0%, 0%-10%, 10%-25%, or >25% DAWM) per brain lobe. Baseline DAWM ratings and white matter hyperintensity (WMH) volumes were associated with memory, executive function, and processing speed cognitive domain <i>z</i>-scores at baseline and their change at follow-up (after 5.2 ± 0.2 years) and with dementia status assessed at long-term follow-up (after 10.3 ± 2.2 years). This was performed by statistical models adjusted for age, sex, vascular risk factors, and education (for the cognition analyses).<h4>Results</h4>From 4,163 included participants, 2,081 participants were selected based on limited baseline WMH volume on FLAIR MRI (determined by a median split) (mean age: 74.6 ± 4.9 years, 61% female). Baseline DAWM

Dementia is a growing global health challenge, yet many determinants of late-life cognitive decline emerge decades before symptoms appear. Midlife is a practical window for prevention because hypertension, diabetes, obesity, dyslipidemia, smoking, physical inactivity, unhealthy diet, sleep disturbance, and social isolation can be identified and modified before substantial brain injury becomes apparent. This narrative review synthesizes evidence linking midlife vascular and lifestyle exposures to late-life cognitive impairment and dementia. The most consistent data support a life-course model in which cumulative vascular, metabolic, inflammatory, and behavioral risks interact with neurodegenerative pathology and cognitive reserve. Vascular and metabolic factors act largely through small-vessel disease, endothelial dysfunction, and inflammation, whereas physical activity, healthy diet, sleep, and social engagement may strengthen resilience. Although observational evidence is vulnerable to confounding and single-risk trials may underestimate cumulative benefit, multidomain prevention remains biologically plausible and clinically actionable, as recent trials reaffirm. These priorities are especially salient in the rapidly transitioning Gulf Cooperation Council (GCC) countries, where midlife cardiometabolic risk is high and local evidence is limited. Dementia prevention should be embedded in routine midlife care, with vascular risk management and sustained lifestyle support treate