Bekena, Semere

Background African American adults experience a disproportionate burden of dementia, shaped by structural and clinical factors that remain unclear. Objective To quantify associations between multimorbidity, polypharmacy, and cognition in the context of neighborhood disadvantage. Methods This study is a cross-sectional analysis of 348 African American adults aged 45–92 years (mean 64.3 years; 73.6% female) from the Aging Research Characterizing Health Exposome via Social drivers (ARCHES) cohort. Comorbidity burden was assessed using a modified Charlson Comorbidity Index (CCI), polypharmacy as ≥5 medications, and neighborhood disadvantage using the Area Deprivation Index (ADI). Linear regression estimated associations with a Preclinical Alzheimer’s Cognitive Composite (PACC). The polypharmacy model included modified CCI as a covariate, and effect modification by ADI was assessed using an interaction term between polypharmacy and ADI. Results Higher modified CCI was associated with lower cognitive performance (B = −0.071; 95% CI: −0.130, −0.012). Polypharmacy was not independently associated with cognition after modified CCI adjustment (B = −0.081; β = −0.057; p = 0.257). No significant ADI interaction was found (p = 0.064).

Background Hearing 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. Objective To examine cross-sectional and longitudinal associations between HI, clinical cognitive status, and AD biomarkers in community-dwelling older adults. Methods We 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) Aβ 42 /Aβ 40 , t-tau/Aβ 42 , and p-tau/Aβ 42 ratios and amyloid PET imaging. Multivariable linear, logistic, Cox proportional hazards, and Fine–Gray competing-risk models were used. Results HI 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. Conclusions In 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.

Background Black adults experience disproportionately higher rates of Alzheimer's disease and related dementias (ADRD), yet remain underrepresented in blood-based biomarker research. Understanding how plasma biomarkers relate to cognitive performance is essential for equitable detection and monitoring of ADRD. Objective We examined cross-sectional and longitudinal associations of both core and non-core plasma biomarkers and cognition in a community-based cohort of Black adults. Methods Participants from the ARCHES study completed baseline plasma biomarker assessments and neuropsychological testing, including a Preclinical Alzheimer Cognitive Composite (PACC) score and the Montreal Cognitive Assessment (MoCA). Plasma biomarkers reflecting amyloid, tau, neurodegeneration, and astrocytic activation were quantified using immunoprecipitation–mass spectrometry and ultrasensitive immunoassay platforms. Linear regression was used to evaluate cross-sectional associations between biomarkers and cognition. Linear mixed-effects models examined whether baseline biomarker levels were associated with cognitive change over one year, adjusting for age, sex, and education. Results The sample included 334 participants with a mean baseline age of 64.6 years (SD = 10.1; range, 45–92.9). Cross-sectionally, higher brain-derived phosphorylated tau 181 was associated with poorer MoCA score (p = 0.04), and neurofilament light chain (NfL) level was also associated with lower PACC score (p = 0.04). Longitudinally, higher baseline NfL and glial fibrillary acidic protein (GFAP) were associated with faster cognitive decline (p < 0.001 and p = 0.018). Conclusions Non-core NfL and GFAP biomarkers are associated with both cross-sectional and longitudinal cognitive performance. These findings highlight the importance of inclusive biomarker research and suggest non-core biomarkers may be particularly informative for characterizing cognitive aging and decline in this population.

ABSTRACT Background Driving supports independence and quality of life in later life but is vulnerable to age‐related and/or disease‐related decline. While cognitive impairment is a well‐recognized risk for unsafe mobility, the contribution of sensorimotor function is less understood. Methods We studied 374 cognitively normal older adults (Clinical Dementia Rating = 0 at baseline) enrolled in the DRIVES Project. A SensoryMotor Impairment Index (SMI) was constructed from six domains (grip strength, gait speed, reaction time, hearing, vision, olfaction) and categorized as 0, 1, 2, or ≥ 3 impairments. Naturalistic driving was continuously monitored using in‐vehicle GPS dataloggers between 2019 and 2025. Linear mixed‐effects models tested whether longitudinal driving trajectories differed by baseline SMI, adjusting for age, sex, race, education, body mass index, and cognition (Preclinical Alzheimer's Cognitive Composite). Results At baseline, participants with higher SMI burden were older and had lower cognitive scores (both p < 0.01). Over time, greater sensorymotor impairment was associated with faster declines in driving exposure and spatial range. Compared with SMI = 0, participants with SMI ≥ 3 showed steeper reductions in nighttime trips (−0.050 vs. −0.037 trips/month), long‐distance trips (> 20 miles; p < 0.001), and maximum trip distance ( p = 0.009), and greater contraction of driving space (entropy and radius of gyration; p < 0.001). Self‐reported driving behaviors showed that participants with higher SMI drove fewer days per‐week and were more likely to avoid night driving ( p < 0.01). Rates of self‐reported adverse driving events (e.g., crashes or citations) did not differ significantly across SMI groups, consistent with compensatory self‐regulatory behaviors. Conclusion Greater sensorymotor impairment predicts accelerated decline in naturalistic driving among cognitively normal older adults, independent of cognition. A composite SMI may provide a feasible, low‐cost approach to identify older drivers at risk for declining mobility and support timely interventions to prolong safe driving.