Research reveals ethnoracial differences in Alzheimer's disease

A team of Mayo Clinic researchers found that Hispanic-American patients with Alzheimer's disease tended to survive with the disease much longer than other ethnoracial groups, according to a study conducted in May. Alzheimer's and dementia: the journal of the Alzheimer's badociation. It was found that Americans of Hispanic origin lived an average of 12 years with the disease from the onset of symptoms.

"This study used one of the largest series of brain tissues given to date, examining the demographic and clinicopathological characteristics of Alzheimer's disease in a diverse ethnoracial case group," said Melissa Murray , Ph.D., translational neuropathologist and investigator director on the Mayo campus in Florida.

The research team examined 1,625 brain tissue samples and compared the progression and duration of the disease in individuals identified as Hispanic, Caucasian, non-Hispanic or African American. Hispanic-American patients had dementia symptoms characteristic of Alzheimer's disease at an average age of 70 years, a year or older earlier than other groups. They were more likely to have a family history of dementia. And they had lower cognitive scores at the end of life. However, the average duration of Alzheimer's disease – the lifespan of patients after the onset of their symptoms – was 12 years for Americans of Hispanic origin, compared to nine years for non-Hispanic whites and eight-year-olds for African Americans.

The Mayo Clinic study compared the presence, location and composition of Alzheimer's disease-related protein blocks, called entanglements, in tissue samples from the FLAM cohort (Florida Autopsied Multi-Ethnic). Researchers found subtle differences between ethnoracial groups in the severity of entanglements, but no difference in brain weight was found. Americans of Hispanic origin were slightly less likely to have the genetic variant, known as APOE ε4, which would increase the risk of Alzheimer's disease. The study also highlighted distinctions in the distribution in the brain of Alzheimer-specific proteins and the presence of simultaneous neurodegenerative processes, which could be useful for research on biomarkers to diagnose the disease.

The study also explored demographic details, such as the education and employment of patients, which are thought to have protective effects against cognitive decline. Compared to non-Hispanic whites, it was found that American Hispanics and African-Americans had less education, which coincides with other risk factors for Alzheimer's disease, such as A lower socio-economic benefit and an increase in cardiovascular disease. "While the field is moving toward Alzheimer's treatment, ethnoracial differences need to be taken into account," says Dr. Murray.

Dr. Murray adds that the study focuses on the size of tissue samples from underrepresented groups. Sixty-seven autopsy-confirmed Alzheimer's samples came from people who identified themselves as Hispanic. Most of them are of Caribbean origin, mainly from Cuba and Puerto Rico, and some of Mexican, Central or South American origin. The study also included brain tissue samples from 19 self-identified African-Americans. "Hispanic and African-American populations tend to be underrepresented in Alzheimer's research, despite the risk of getting the disease one to two times higher, compared to non-Hispanic white Americans," says Dr. Murray. "Our hope is that our findings will help Hispanic Americans and African Americans overcome historical and cultural barriers to research, and our results on longevity could have important consequences in terms of addressing disparities between people." family impact and cost of care ".

The results also spur the next stage of the investigation, examining factors that can affect the survival of Hispanic-American patients, says Dr. Murray. His team will explore psycho-social factors, such as family support and potential neurobiological factors, including protective proteins.

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Mayo Clinic