Lower Prevalence of Asymptomatic Alzheimer's Disease Among Healthy African Americans.

OBJECTIVE: Alzheimer's disease (AD) is believed to be more common in African Americans (AA), but biomarker studies in AA populations are limited. This report represents the largest study to date examining cerebrospinal fluid AD biomarkers in AA individuals. METHODS: We analyzed 3,006 cerebrospinal fluid samples from controls, AD cases, and non-AD cases, including 495 (16.5%) self-identified black/AA and 2,456 (81.7%) white/European individuals using cutoffs derived from the Alzheimer's Disease Neuroimaging Initiative, and using a data-driven multivariate Gaussian mixture of regressions. RESULTS: Distinct effects of race were found in different groups. Total Tauand phospho181-Tau were lower among AA individuals in all groups (p < 0.0001), and Aß42 was markedly lower in AA controls compared with white controls (p < 0.0001). Gaussian mixture of regressions modeling of cerebrospinal fluid distributions incorporating adjustments for covariates revealed coefficient estimates for AA race comparable with 2-decade change in age. Using Alzheimer's Disease Neuroimaging Initiative cutoffs, fewer AA controls were classified as biomarker-positive asymptomatic AD (8.0% vs 13.4%). After adjusting for covariates, our Gaussian mixture of regressions model reduced this difference, but continued to predict lower prevalence of asymptomatic AD among AA controls (9.3% vs 13.5%). INTERPRETATION: Although the risk of dementia is higher, data-driven modeling indicates lower frequency of asymptomatic AD in AA controls, suggesting that dementia among AA populations may not be driven by higher rates of AD. ANN NEUROL 2024.

Photojournalism-Based Intervention Reduces Caregiver Burden and Depression in Alzheimer's Disease Family Caregivers.

Purpose: Art interventions have demonstrated holistic benefits for persons living with dementia and their caregivers. In this article, we describe the results of a pilot photojournalism program for 10 unpaid caregivers of persons living with dementia, with respect to caregivers' experience in the program and their psychological well-being. Design: Caregivers participated in four sessions led by a professional photojournalist who taught principles of photography. Between the sessions, caregivers took photographs that represented what caregiving meant to them using digital cameras provided in the program. During the sessions, instruction was interspersed with discussion of caregivers' photographs. Method: Caregiver burden and depressive symptoms were measured pre- and postprogram. Qualitative exploration included sessions' observations, viewing caregivers' photographs, and recording caregivers' accompanying comments. Findings: For participants with pre- and postprogram data, caregiver burden decreased significantly (p = .037). For caregivers with pre- and postprogram data, depressive symptoms decreased nonsignificantly (p = .066). Clinically meaningful reductions in caregiver burden and depressive symptoms were attained. Qualitative findings highlighted caregivers' strong engagement with the project, the facilitator, and other participants, and reflection on multiple aspects of their experience. Conclusions: This intervention helped caregivers creatively communicate their experience and demonstrated efficacy in the improvement of caregivers' psychological well-being.

Race modifies the relationship between cognition and Alzheimer's disease cerebrospinal fluid biomarkers.

BACKGROUND: African Americans have been reported to have a higher prevalence of Alzheimer's disease (AD) than Caucasians, but etiology-specific AD biomarkers have not been systematically analyzed in older African Americans. Coexisting cerebrovascular disease may also contribute to this increased prevalence. We hypothesized that cerebrospinal fluid (CSF) biomarkers of amyloid, neurodegeneration, and endothelial dysfunction would differ between older African Americans and Caucasians with normal cognition and cognitive impairment associated with AD. METHODS: We prospectively recruited 135 older Americans to undergo detailed clinical, neuropsychological, genetic, magnetic resonance imaging (MRI), and CSF analysis from 2013 to 2015 at Emory University (Atlanta, GA, USA). We compared levels of CSF markers for ß-amyloid (Aß42, Aß40), total and phosphorylated tau (t-tau and p-tau181, respectively), endothelial dysfunction (soluble vascular cell adhesion molecule 1, soluble intercellular adhesion molecule 1), α-synuclein, and neurodegeneration (neurofilament light chain [NfL]), as well as MRI markers, for hippocampal atrophy and cerebrovascular disease (white matter hyperintensity [WMH] volume). RESULTS: Sixty-five older African Americans (average age, 69.1 years) and 70 older Caucasians (average age, 70.8 years) were included. After adjusting for demographic variables, AD risk alleles, and cognitive function, older African Americans had lower CSF levels of p-tau181 (difference of 7.4 pg/ml; 95% CI, 3.7-11.2 pg/ml; p < 0.001), t-tau (difference of 23.6 pg/ml; 95% CI, 9.5-37.7; p = 0.001), and Aß40 (difference of 1.35 ng/ml; 95% CI, 0.29-2.42 ng/ml; p = 0.013) despite similar levels of Aß42, NfL, WMH volume, and hippocampal volume. Cognitively impaired African Americans also had lower CSF t-tau/Aß42 (difference of 0.255 per 1-SD change in composite cognition; 95% CI, 0.100-0.409; p = 0.001) and p-tau181/Aß42 (difference of 0.076 per 1-SD change in composite cognition; 95% CI, 0.031-0.122; p = 0.001). These could not be explained by measured biomarkers of non-AD processes, but African Americans may be more susceptible than Caucasians to the cognitive effects of WMH. CONCLUSIONS: Despite comparable levels of CSF Aß42 and Aß42/Aß40, cognitive impairment in African Americans is associated with smaller changes in CSF tau markers but greater impact from similar WMH burden than Caucasians. Race-associated differences in CSF tau markers and ratios may lead to underdiagnosis of AD in African Americans. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02089555 . Retrospectively registered on 14 March 2014.

Knowledge and Attitudes in Alzheimer's Disease in a Cohort of Older African Americans and Caucasians.

African American participation in Alzheimer's disease (AD) research studies has been historically low. To determine whether older African Americans and Caucasians had different knowledge or attitudes related to AD, we administered the Alzheimer's Disease Knowledge Scale (ADKS) to 67 older African Americans and 140 older caucasians in the greater Atlanta area as well as questions targeting locus of control over general health and AD risks. Older African Americans scored slightly lower on ADKS than older caucasians, with race only accounting for 1.57 (95% confidence interval [CI] 0.57-2.61, P < .001) points of difference in a multivariate model. Attitudes toward AD were also similar between the 2 groups but 1 (35.7%) in 3 adults reported control over general health but not AD risks. In addition to enhancing education content in outreach efforts, there is an urgent need to address the perception that future AD risks are beyond one's own internal control.