NASHVILLE — A large multisite study led by Vanderbilt Health researchers found that Black and Hispanic older adults with cognitive impairment are less likely than other racial and ethnic groups to show Alzheimer’s pathology on brain scans. The study included 5,757 Medicare recipients across the U.S. with mild cognitive impairment or dementia, of whom 22% were Black, 20% Hispanic, and 58% were classified as 'any other racial/ethnic group' (AORE).
Compared to AORE participants, the odds of amyloid positivity—a hallmark of Alzheimer’s disease—were 28% lower among Black individuals and 22% lower among Hispanic individuals. Black and Hispanic participants were also more likely to present at the dementia stage rather than with mild cognitive impairment and were more than twice as likely to be enrolled in Medicare Advantage plans.
The study tracked nonmedical drivers of health, including gender, education, Medicare coverage type, and the area deprivation index (ADI), which categorized neighborhoods into prosperous, comfortable, mid-tier, at-risk, and distressed. Odds of amyloid positivity were 22% higher in comfortable areas and 40% higher in distressed areas compared to prosperous ones. No differences in amyloid positivity were observed by gender, education level, or Medicare coverage type. "These results suggest that the yawning ethnoracial differences in dementia may be driven in part by group differences in underlying causes of dementia symptoms," said Consuelo Wilkins, Mildred Thornton Stahlman Professor in Rural Health and professor of Medicine in the Division of Geriatric Medicine.
Corey Bolton, assistant professor of Medicine in the Division of Geriatric Medicine, added, "Among people with cognitive impairment, normal PET results may lessen treatment access and clinical trial eligibility. Our results confirm that these disadvantages are apt to fall inordinately on Black and Hispanic people. Meanwhile, our finding that odds for PET positivity were 40% greater in the most disadvantaged areas compared to the most prosperous areas was another signal result of this study."
Wilkins also cautioned that a fixation on Alzheimer’s pathology could worsen existing health disparities. "We need desperately to combat the scourge of Alzheimer's, but our results highlight that a fixation on Alzheimer's pathology, to the exclusion of other causes of dementia, could inadvertently worsen stark ethnoracial health differences. Our findings urge further study."