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NIA: Data shows racial disparities in Alzheimer's
disease diagnosis between Black and white research study participants
  December 16, 2021
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Black participants in Alzheimer's disease research studies were 35% less likely to be diagnosed with Alzheimer's and related dementias than white participants, despite national statistics that indicate that Black Americans are overall about twice as likely to develop dementias than whites.
Previous studies have shown that for the overall U.S. population, Black Americans are roughly 1.5 to 2 times as likely than whites to develop Alzheimer's and related dementias.
At baseline visits, the data showed that 26.8% of Black participants were diagnosed with Alzheimer's or related dementias, as opposed to 36.1% of white participants.
Researchers, led by Keenan Walker, Ph.D., from the NIA Intramural Research Program, found that Black study participants showed higher rates of cognitive impairment, particularly on measures of processing speed, executive function, and language, compared with white participants. Black participants also had higher rates of hypertension and diabetes, potential risk factors for Alzheimer's and related dementias.
The research team found that neuropsychiatric symptoms were also more likely to occur in diagnosed Black participants than in white participants with a similar diagnosis. After accounting for demographic factors and education, Black participants were about twice as likely as white participants to experience delusions and hallucinations. Black participants were also more likely to have other symptoms, including agitation/aggression, loss of inhibition, irritability, motor disturbances, and abnormal sleep, behavioral, and appetite/eating changes. Black and white participants did not show significant differences in affective or anxiety symptoms, or apathy and indifference, other symptoms of Alzheimer's and related dementias.
The investigators see their results as further evidence that Black patients often have to present with more severe clinical presentations to warrant a diagnosis of dementia from physicians than white patients. This is consistent with numerous studies that showed Black individuals were not being diagnosed with Alzheimer's or related dementias or seeking treatment until the disease process was more advanced.
The investigators are not yet clear on the reasons behind these findings but suspect they can be explained in part by a referral bias or differences in diagnostic thresholds applied by providers. They see this study as further evidence for addressing racial disparities in Alzheimer's disease and related dementias treatment, especially to avoid delayed diagnoses that could have major adverse consequences for patients and their families.


According to the US Census Bureau,6 the US population is approximately 76.5% White and 13.4% Black, excluding those who identify as bi- or multiracial. Among those 65 years and older, Black individuals have the highest reported risk of ADRD [Alzheimer's disease and related dementias] relative to other racial groups…..most common and conservative finding is that Black individuals are roughly 1.5 to 2 times as likely to develop AD compared to White individuals.
This study retrospectively investigated the racial representation of non-Hispanic Black and White individuals within a national ADRD medical research database, and examined race differences in cognitive performance, neuropsychiatric symptoms, and functional impairment. The prevalence of dementia diagnoses among non-Hispanic Black participants was significantly lower than that of non-Hispanic White participants among the NACC dataset, an unexpected result given that the prevalence of dementia among Black individuals tends to be higher than that of White individuals in community-based samples.35 This finding was especially surprising given that known risk factors for dementia (e.g., hypertension, diabetes) were consistently higher among Black participants in this sample, mirroring prior literature.36
research purports that Black individuals seek medical treatment for AD at a more advanced stage because of social attitudes and beliefs held within the Black American community that memory loss is a typical part of normal aging.4, 47-49 Consequently, Black individuals are more likely to seek medical attention for neuropsychiatric symptoms such as hallucinations, delusions, and personality changes rather than memory concerns.
In sum, it is becoming increasingly clear that sociocultural factors contribute to inadequate or delayed treatment of ADRD in racial/ethnic minority populations. The current findings corroborate this assertion in that non-Hispanic Black participants in a national ADRD medical research database had a lower prevalence of dementia diagnoses at initial visit, despite having comparable or worse dementia risk factors, and comparatively greater cognitive impairment, neuropsychiatric symptoms, and functional limitations. There are multiple avenues through which clinicians and researchers can begin remedying these inequities in ADRD diagnosis, treatment, and research. These efforts include increasing representation of Black individuals in ADRD research by facilitating closer partnerships with minority communities and working with local civic leaders and organizations, as well as targeted oversampling.58 It will also be critical to develop regression-based normative approaches to aid neuropsychologists in accounting for known social determinants of brain health. In addition, biological diagnostic approaches may help facilitate more accurate prevalence estimates of ADRD in diverse populations. Finally, it is incumbent on the medical community to cultivate trust and provide education on ADRD to promote more equitable access to health care and increased enrollment in clinical research for racial/ethnic minority populations.


02 December 2021 Alzheimers & Dementia

Although dementia prevalence differs by race, it remains unclear whether cognition and neuropsychiatric symptom severity differ between Black and White individuals with dementia.
Using National Alzheimer's Coordinating Center (NACC) data, we evaluated dementia prevalence in non-Hispanic Black and White participants and compared their clinicodemographic characteristics. We examined race differences in cognition, neuropsychiatric symptoms, and functional abilities in participants with dementia using multivariable linear and logistic regression models.
We included 5,700 Black and 31,225 White participants across 39 Alzheimer's Disease Research Centers.
Of these, 1,528 (27%) Black and 11,267 (36%) White participants had dementia diagnoses. Despite having lower dementia prevalence, risk factors were more prevalent among Black participants.
Black participants with dementia showed greater cognitive deficits, neuropsychiatric symptoms/severity, and functional dependence.

Despite lower dementia prevalence, Black participants with dementia had more dementia risk factors, as well as greater cognitive impairment and neuropsychiatric symptom severity than White participants.
Alzheimer's disease and related dementias (ADRD) are a group of disorders characterized by a decline in cognitive functioning leading to loss of independence.1 Currently, Alzheimer's disease (AD) is the sixth leading cause of death in the United States and the fifth leading cause of death among adults age 65 and older.2 Recent estimates suggest that 6.1 million people had clinical AD or mild cognitive impairment (MCI) due to AD in 2017, a number expected to grow to 15 million by 2060.3 Alongside the increased prevalence of ADRD in the United States, changes in the demographic composition of the country are also anticipated in coming decades. Current projections suggest that, by 2050, 42% of the nation's older adults will be racial/ethnic minorities.4, 5 Given the expected growth rate of ADRD is highest among racial/ethnic minority groups, this confluence of factors warrants vigilant attention to address existing healthcare disparities and ensure equitable access to care is available for at-risk groups.1
According to the US Census Bureau,6 the US population is approximately 76.5% White and 13.4% Black, excluding those who identify as bi- or multiracial. Among those 65 years and older, Black individuals have the highest reported risk of ADRD relative to other racial groups.7 For example, although empirical estimates suggest the prevalence of AD in Black individuals is highly variable, ranging from 14% to 500% greater than their White counterparts,8 the most common and conservative finding is that Black individuals are roughly 1.5 to 2 times as likely to develop AD compared to White individuals.9-11
Among the factors that may contribute to these observed discrepancies, dementia risk factors deserve close consideration. Although race is not a biological distinction, certain physiological characteristics, diseases, and lifestyle factors associated with dementia risk differentially impact members of racial/ethnic minority groups.2, 12-17 Here, we define dementia risk factors as a set of physiological variables (e.g., body mass index [BMI], blood pressure), cardiovascular conditions (e.g., hypertension, diabetes mellitus, stroke, myocardial infarction, congestive heart failure), and lifestyle factors (e.g., smoking) that have been consistently associated with dementia and late-life cognitive decline.18-20 The emergence of these dementia risk factors may be driven by more distal factors such as socioeconomic status, healthcare access/insurance coverage, clinical presentation, and timing of diagnosis.12, 15, 21-23 Beyond consideration of the race-specific distribution of dementia risk factors, the co-occurrence of neuropsychiatric symptoms deserves additional attention to further address barriers to accurate and early diagnosis of ADRD among racial/ethnic minority groups.
Neuropsychiatric symptoms are common in ADRD.24 These symptoms are interdependent and present in a heterogeneous manner across individuals.25 For example, neuropsychiatric symptoms accompanying ADRD may include hallucinations, delusions, agitation, aggression, apathy, depression, and insomnia.26 Clinical presentation of ADRD may also vary by racial/ethnic group or may be impacted by cultural factors. For instance, some research has suggested that Black individuals more frequently report hallucinations in conjunction with probable AD diagnosis.27 Additionally, Black participants with AD reported more frequent insomnia, greater functional impairment, and a shorter duration of illness at the time of initial diagnosis in another study.28 These variations in clinical presentation may undermine diagnostic accuracy, as there is evidence that missed diagnosis of ADRD is more common among older Black and Hispanic/Latinx individuals than among older White individuals.29, 30

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