Interactive Effects of Plasma Alzheimer Disease Biomarkers and White Matter Hyperintensities on Cognitive Decline and Clinical Progression in Nondemented Adults.

MRI-derived brain aging trajectories across the Alzheimer's continuum: links to cognition, pathology and lifestyle risk factors

BAG is a reliable non-invasive marker of structural brain health sensitive to AD pathology and to modifiable AD risk and supports its relevance for early risk stratification and prevention-oriented research.

Prognostic Value of Blood-Based P-Tau217 Levels for Progression to Cognitive Impairment.

Importance Blood-based biomarkers for Alzheimer disease, particularly plasma phosphorylated tau 217 (p-tau217), accurately reflect early Alzheimer disease brain pathology in cognitively unimpaired individuals, but estimates of absolute risk of progression to cognitive impairment across multiple cohorts are needed. Objective To estimate absolute risk of progression to cognitive impairment and rates of cognitive decline based on plasma p-tau217 across cognitively unimpaired older adults. Design, Setting, and Participants Longitudinal cohort study using harmonized data from 2684 cognitively unimpaired older adults (defined within cohort) across 6 observational and clinical trial cohorts based in North America, Japan, and Australia. The earliest enrollment was in 2004, with most recent follow-up in 2025. Exposure Baseline plasma p-tau217. Main Outcomes and Measures The primary outcome was time to progression to cognitive impairment (mild cognitive impairment, dementia, or 2 consecutive global Clinical Dementia Rating scores ≥0.5). The secondary outcome was longitudinal change on the latent Preclinical Alzheimer Cognitive Composite (PACC; higher values indicate better performance). Results Among the 2684 participants (median [IQR] age, 69.6 [66.2-74.2] years; 1697 [63%] female), there were 478 events of progression to cognitive impairment over a median follow-up of 5.4 years (maximum follow-up of 13.5 years). Each 1-SD increase in baseline p-tau217 level was associated with an increased risk of progression to cognitive impairment (hazard ratio, 1.38 [95% CI, 1.30-1.46]), and the association remained significant after adjustment, including β-amyloid positron emission tomography scan Centiloids (hazard ratio, 1.32 [95% CI, 1.24-1.41]). Participants with high (1.1-2.4 SD) and very high (>2.5 SD) baseline p-tau217 had 24% (95% CI, 20%-28%) and 38% (95% CI, 33%-43%) absolute risk of progression over 5 years, respectively, and risk was markedly higher over 10 years, although longer-term estimates were constrained by limited data. Elevated p-tau217 was also associated with faster cognitive decline based on change in latent PACC score. Among the overall sample, baseline latent PACC scores ranged from -0.8 to 2.7. The 5-year annualized decline for the very high p-tau217 group was -0.07 latent PACC units/y (95% CI, -0.10 to -0.05), relative to 0.03 units/y (95% CI, 0.02-0.04) in the low p-tau217 group. Conclusions and Relevance In a pooled sample of multiple selected cohorts of cognitively unimpaired older adults, higher plasma p-tau217 levels were consistently associated with increased risk of clinical progression and accelerated cognitive decline. By providing time-specific absolute risk estimates, these findings support the potential of p-tau217 for prognostic model development, with direct implications for future trial design. Further validation in unselected populations is needed to inform individual prognosis and clinical decision-making in cognitively unimpaired individuals.

Hearing in noise and cognitive status in older adults: Biomarker associations and bidirectional survival analyses.

BackgroundHearing impairment (HI) has been identified as a potentially modifiable risk factor for dementia, yet its relationship with Alzheimer's disease (AD) neuropathology and the temporal directionality remain unclear, particularly in late life.ObjectiveTo examine cross-sectional and longitudinal associations between HI, clinical cognitive status, and AD biomarkers in community-dwelling older adults.MethodsWe included 474 DRIVES Project participants (mean age 73.5 ± 5.2 years). Hearing was assessed using the NIH Toolbox Words-in-Noise (WIN) test. Clinical cognitive status was assessed using Clinical Dementia Rating (CDR). AD biomarkers included cerebrospinal fluid (CSF) Aβ42/Aβ40, t-tau/Aβ42, and p-tau/Aβ42 ratios and amyloid PET imaging. Multivariable linear, logistic, Cox proportional hazards, and Fine-Gray competing-risk models were used.ResultsHI was more prevalent among participants with mild cognitive impairment (MCI; defined as CDR = 0.5) than cognitively normal individuals (50% versus 24%, p < 0.001), and MCI status was independently associated with worse baseline WIN thresholds (β = 1.55 dB SNR; 95% CI 0.72-2.37). HI was not cross-sectionally associated with CSF amyloid or tau ratios or amyloid PET positivity. Longitudinally, baseline MCI was associated with a higher risk of incident HI (Cox HR = 2.63, 95% CI 1.48-4.67; Fine-Gray sHR = 2.79, 95% CI 1.06-7.40), whereas baseline HI was not associated with subsequent CDR progression.ConclusionsIn older adults, HI was associated with MCI but not core AD biomarkers or future CDR progression, suggesting that late-life HI may reflect cognitive vulnerability or broader brain aging rather than independently driving AD pathology.

A cerebrospinal fluid blood–brain barrier dysfunction score is associated with progression from mild cognitive impairment to Alzheimer's disease

Parallel neuroinflammatory pathways to cerebrovascular burden and amyloid beta in Alzheimer's disease

Higher plasma YKL‐40 was associated with greater white matter hyperintensity (WMH), whereas higher plasma GFAP was related to increased 18F‐florbetapir (FBP) standardized uptake value ratio (SUVR) and higher plasma p‐tau217 was associated with reduced MTL cortical thickness and hippocampal volume.

Cerebral amyloid-β burden and white matter injury: associations, clues for underlying mechanisms, and implication on cognitive trajectory after lecanemab therapy.

INTRODUCTION White matter hyperintensities (WMH) are linked to cognitive decline and risk of Alzheimer's disease (AD). OBJECTIVES To test whether amyloid-β (Aβ) deposition contributes to white matter injury and whether WMH dynamics can modulate the clinical efficacy of the anti-Aβ therapy. METHODS Twenty patients with early AD who are receiving lecanemab and a matched cohort of 110 untreated AD patients were followed. Linear mixed-effects models were used to examine the interplay between WMH trajectories and lecanemab on cognitive decline. The roles of Aβ burden in predicting baseline severity and progression rates of WMH were evaluated in a larger cohort of 1,031 adults. Finally, cerebrospinal fluid (CSF) proteomic and bioinformatic analyses were performed to identify potential candidate mediators and pathways linking Aβ to WMH progression. RESULTS Following lecanemab treatment (median = 13 times), 80 % of patients showed WMH reductions, predominantly in periventricular and frontoparietal regions. Compared to the reference cohort, WMH progression is significantly slower among those with anti-Aβ therapy. WMH trajectory significantly modified the relationship between anti-Aβ therapy and cognitive decline, with greater cognitive improvement observed among those with smaller WMH reductions. The levels of Aβ burden were correlated with higher burden and accelerated rates of WMH. Eight proteins in CSF were identified as candidate mediators linking WMH to Aβ. They were enriched in vascular-endothelial, neuro-cytoskeletal, and neuroinflammation pathways. CONCLUSION The interplay of Aβ with white matter integrity contributes to cognitive decline in the context of Alzheimer's disease.