Dementia diagnosis; dementia difference

SACRAMENTO, Calif.—According to a new study from the Alzheimer’s Center at the University of California, Davis (UC Davis), there are major differences in the brains of Latinx subjects with a dementia diagnosis as compared with those of Caucasian and Black patients.

Published in the Journal of Alzheimer’s Disease, the study analyzed autopsied brains and determined that Latinx people diagnosed with dementia were much more likely to have cerebrovascular disease than either Caucasians or Black individuals. Researchers also discovered that Latinx and Black patients were more likely to have mixed pathologies; that is, a combination of Alzheimer’s disease and cerebrovascular disease, than is the case with Caucasians.

Also, Caucasians had more pure Alzheimer’s disease (rather than co-morbid disease) than either Latinx or Black individuals. Researchers hope the findings help to explain the higher rates of dementia among Black and Latinx patients and might be able to bring attention to the importance of treating each patient based on their individual risk factors, including racial ones.

According to Charles DeCarli, director of the Alzheimer’s Disease Center and principal investigator on the study, “It’s a way to tailor our approach to the individual, and it’s something we want to do as early as possible. Our idea was to move from just a clinic-based referral system to then create a community-based recruitment system, where we could broaden the range of people who are being evaluated.”

Recognizing a need to broaden the range of individuals being evaluated by physicians for dementia, DeCarli began the research 15 years ago. He wanted to overcome the potential bias of research based on the statistics for the Caucasian people who have historically sought help for memory problems. If someone is Latinx and diabetic or Black and hypertensive, that person is probably at higher risk for dementia, and these risks should be addressed aggressively, according to DeCarli.

For the recent study, researchers analyzed brain tissue from 423 people who had died after a dementia diagnosis between 2000 and 2017. All of the subjects had been seen at one of the two UC Davis Alzheimer’s Disease Center clinics. There were 360 Caucasians patients, 35 Black patients and 28 Latinx patients. They discovered a mixed diagnosis of dementia—both Alzheimer’s disease and cerebrovascular disease—in 37 percent of Caucasian subjects and 37 percent of Black subjects, but 54 percent of Latinx ones. Only 4 percent of Caucasian people had only cerebrovascular disease, compared with 11 percent of Black people and 21 percent of Latinx people. Pure Alzheimer’s disease (without cerebrovascular disease) was discovered in 43 percent of Caucasians and 43 percent of Black patients, but only 14 percent of Latinx ones.

According to Dr. Brittany Dugger, an assistant professor in the UC Davis School of Medicine’s Department of Pathology and Laboratory Medicine who also works in the UC Davis Alzheimer’s Disease Center and was corresponding author on the paper, “Alzheimer’s disease is still the leading cause of dementia. However, many cases may have cerebrovascular disease (a disease that affects the blood vessels of the brain) in addition to Alzheimer’s disease, as our study showed. Having diabetes and/or hypertension can increase both the likelihood of getting cerebrovascular disease and Alzheimer’s disease.”

As to the next steps in the research, Dugger said, “We hope to do more comprehensive analyses of brains, delving deeper into the who, what, where, when, why and how. This research is only the tip of the iceberg. Most brain research on dementia is based on a small subset of volunteers who are typically white; it is imperative to understand the spectrum of disease across individuals from diverse backgrounds and regions as we can have differences in our behaviors and cultures, as well as social and economic factors.”