Black participants in Alzheimer’s disease research studies were 35% less likely to be diagnosed with Alzheimer’s and related dementias than white participants, according to a recent analysis, despite evidence indicating that that Black Americans are overall about twice as likely to develop Alzheimer’s and other dementias than whites.
The study also revealed that Black participants with Alzheimer’s and related dementias had more risk factors for the disease, greater cognitive impairment and symptom severity than white participants.
These findings offer an opportunity for journalists to educate their audience(s) about risk, prevalence, warning signs and the need for more provider and consumer education about dementia in underserved populations.
A glance at the research
The analysis was conducted among participants in the National Institute on Aging’s network of Alzheimer’s Disease Research Centers (ADRCs) located at major medical institutions throughout the U.S. The goal of these centers is to translate research advances into improved diagnosis and care for people with Alzheimer’s disease and related dementias.
For the current study, investigators wanted to determine if there were related racial differences in cognition, neuropsychiatric symptoms, and functional abilities in diagnosed study participants. They tracked 15 years of data (2005-2020) on 5,700 Black and 31,225 white participants using the Uniform Data Set of the National Alzheimer’s Coordinating Center (NACC), which aggregates data from ADRCs from across the country.
Analyzing study results
At baseline, the data showed that 26.8% of Black participants were diagnosed with Alzheimer’s or related dementias compared with 36.1% of white participants. Overall, Black participants had 35% lower odds of having an Alzheimer’s or dementia diagnosis at the initial visit relative to white participants.
Researchers found that Black study participants had higher rates of cognitive impairment, particularly on measures of processing speed, executive function, and language compared with white participants. Black participants also had a greater prevalence of hypertension and diabetes, potential risk factors for Alzheimer’s and related dementias.
And neuropsychiatric symptoms were more likely to occur in diagnosed Black participants than in comparable white participants. After adjusting 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. There were no significant differences by race in affective or anxiety symptoms, or apathy and indifference, other symptoms of this disease.
Disparities in diagnosis are common
These results are further evidence that Black patients often have to present with more severe clinical symptoms to receive a diagnosis of dementia from physicians than do white patients, according to investigators. This is consistent with numerous studies showing later diagnosis and treatment among the Black population for Alzheimer’s or related dementias.
Scientists say these trends may be partly tied to social attitudes and beliefs within the African American community. Many Black older adults tend to seek medical treatment when they encounter neuropsychiatric symptoms such as hallucinations, delusions, and personality changes, but delay help for memory problems, which are often viewed as a normal part of aging.
The investigators are not yet clear on the reasons behind these findings but said it might 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.
The researchers cautioned that the study was limited to a clinic-based population derived from ADRCs and that this analysis may not generalize to the broader U.S. population. Since the study was a targeted comparison between Black and white research study participants, it cannot be extrapolated into any clear trends in overall Alzheimer’s and dementia prevalence for other populations. Researchers hope to expand on this work to include data from other underrepresented groups.
Resources for journalists
- This research shows 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.
- Alzheimer’s Association Racial Disparities Fact sheet(PDF)
- National Institute on Aging Alzheimer’s Disease Research Centers
- The gov website from the National Institutes of Health provides a good overview of related dementias, tips for patients and families, ongoing research and a searchable database of clinical trials.
- The Center for Brain Health at the University of Texas, Dallas, focuses on research that not only helps people with cognitive challenges but looks at ways to maintain a healthy brain as we age.
