Research on racial differences in Alzheimer disease (AD) dementia has increased in recent years. Older African American individuals bear a disproportionate burden of AD and cognitive impairment ...compared with non-Latino white individuals. Tremendous progress has been made over the past two decades in our understanding of the neurobiological substrates of AD. However, owing to well-documented challenges of study participant recruitment and a persistent lack of biological data in the African American population, knowledge of the drivers of these racial disparities has lagged behind. Therapeutic targets and effective interventions for AD are increasingly sought, but without a better understanding of the disease in African American individuals, any identified treatments and/or cures will evade this rapidly growing at-risk population. In this Perspective, I introduce three key obstacles to progress in understanding racial differences in AD: uncertainty about diagnostic criteria, disparate cross-sectional and longitudinal findings; and a dearth of neuropathological data. I also highlight evidence-informed strategies to move the field forward.
As the US elderly population continues to expand rapidly, Alzheimer's disease poses a major and increasing public health challenge, and older African Americans may be disproportionately burdened by ...the disease. Although African Americans were generally underincluded in previous research studies, new and growing evidence suggests that they may be at increased risk of the disease and that they differ from the non-Hispanic white population in risk factors and disease manifestation. This article offers an overview of the challenges of Alzheimer's disease in African Americans, including diagnosis issues, disparities in risk factors and clinical presentation of disease, and community-based recommendations to enhance research with this population.
The Memory and Aging Project is a longitudinal, epidemiologic clinical-pathologic cohort study of common chronic conditions of aging with an emphasis on decline in cognitive and motor function and ...risk of Alzheimer's disease (AD). In this manuscript, we first summarize the study design and methods. Then, we present data on: (1) the relation of motor function to cognition, disability, and death; (2) the relation of risk factors to cognitive and motor outcomes, disability and death; (3) the relation of neuropathologic indices to cognitive outcomes; (4) the relation of risk factors to neuropathologic indices; and (5) additional study findings. The findings are discussed and contextualized.
Introduction
The estimate of people with clinical Alzheimer's disease (AD) and mild cognitive impairment provides an understanding of the disease burden.
Methods
We estimated people with cognitive ...impairment using a quasibinomial regression model in 10,342 participants with cognitive test scores.
Results
The 2020 US Census–adjusted prevalence of clinical AD was 11.3% (95% confidence interval CI = 10.7–11.9): 10.0% among non‐Hispanic Whites, 14.0% among Hispanics, and 18.6% among non‐Hispanic Blacks. We estimate that in 2020, 6.07 (95% CI = 5.75–6.38) million people were living with clinical AD, which increases to 13.85 (95% CI = 12.98–14.74) million in 2060, 423% higher among Hispanics, 192% higher among Blacks, and 63% higher among Whites. However, there are predicted to be more significant increases in later years among those over 85 and women compared to men.
Discussion
The number of people with clinical AD will increase as the “baby boom” generation reaches older ages, exerting a strong upward influence on disease burden.
Research indicates that stress is linked to cognitive dysfunction. However, few community-based studies have explored the relationship between perceived stress and cognitive decline, and fewer still ...have utilized cognitive domains rather than a global measure of cognition.
We examined the relation between perceived stress and the rate of decline in different cognitive domains.
Participants were older African Americans without dementia from the Minority Aging Research Study (MARS; N = 467, mean age: 73 years, SD: 6.1 years). A battery of 19 cognitive tests was administered at baseline and at annual intervals for up to 9 years (mean follow-up: 4 years), from which composite measures of global cognitive function and five specific cognitive domains were derived. The four-item Cohen's Perceived Stress Scale (PSS) was also administered at baseline.
In linear mixed-effects models adjusted for age, sex, education, and vascular risk factors, higher perceived stress was related to faster declines in global cognition (β = -0.019; SE: 0.008; t
= -2.46), episodic memory (β = -0.022; SE: 0.011; t
= -1.99), and visuospatial ability (β = -0.021; SE: 0.009; t
= -2.38) all p < 0.05. Findings were similar in subsequent models adjusted for demographics, vascular diseases, and depressive symptoms.
Results indicate that older African Americans with higher levels of perceived stress have more rapid declines in global cognition than those with lower levels, most notably for episodic memory and visuospatial ability.
Precision medicine methodologies and approaches have advanced our understanding of the clinical presentation, development, progression, and management of Alzheimer's disease (AD) dementia. However, ...sex and gender have not yet been adequately integrated into many of these approaches.
The Society for Women's Health Research Interdisciplinary Network on AD, comprised of an expert panel of scientists and clinicians, reviewed ongoing and published research related to sex and gender differences in AD.
The current review is a result of this Network's efforts and aims to: (1) highlight the current state-of-the-science in the AD field on sex and gender differences; (2) address knowledge gaps in assessing sex and gender differences; and (3) discuss 12 priority areas that merit further research.
The exclusion of sex and gender has impeded faster advancement in the detection, treatment, and care of AD across the clinical spectrum. Greater attention to these differences will improve outcomes for both sexes.
The Minority Aging Research Study (MARS) is a longitudinal, epidemiologic cohort study of decline in cognitive function and risk of Alzheimer's disease (AD) in older African Americans, with brain ...donation after death added as an optional component for those willing to consider organ donation. In this manuscript, we first summarize the study design and methods of MARS. We then provide details of ongoing efforts to achieve neuropathologic data on over 100 African Americans participating in MARS and in three other clinical-pathologic cohort studies at Rush University Medical Center. The results examine strategies for recruiting and consenting African Americans without dementia; (2) efforts to maintain high rates of follow-up participation; (3) strategies for achieving high rates of agreement to brain donation; and (4) the methodology of obtaining rapid brain autopsy at death. The implications of these efforts are discussed.
We examined the association of social activity with cognitive decline in 1138 persons without dementia at baseline with a mean age of 79.6 (SD = 7.5) who were followed for up to 12 years (mean = 5.2; ...SD = 2.8). Using mixed models adjusted for age, sex, education, race, social network size, depression, chronic conditions, disability, neuroticism, extraversion, cognitive activity, and physical activity, more social activity was associated with less cognitive decline during average follow-up of 5.2 years (SD = 2.7). A one point increase in social activity score (range = 1-4.2; mean = 2.6; SD = 0.6) was associated with a 47% decrease in the rate of decline in global cognitive function (p < .001). The rate of global cognitive decline was reduced by an average of 70% in persons who were frequently socially active (score = 3.33, 90th percentile) compared to persons who were infrequently socially active (score = 1.83, 10th percentile). This association was similar across five domains of cognitive function. Sensitivity analyses revealed that individuals with the lowest levels of cognition or with mild cognitive impairment at baseline did not drive this relationship. These results confirm that more socially active older adults experience less cognitive decline in old age.
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