While researchers have known that the ApoE4 genetic variant is the strongest genetic risk factor for Alzheimer’s and related dementias, this finding is largely based on studies of people of European descent.
In a recent study published in the journal Alzheimer’s & Dementia, scientists found that the Amerindian (indigenous American) genetic ancestry is linked to a protective effect against the risk of ApoE4 on significant cognitive decline, furthering their understanding of how the genetic variant may have different effects among populations of Latino backgrounds.
“Latinx populations suffer more from Alzheimer’s and dementia than other populations,” Einat Granot-Hershkovitz, an author on the study and a research fellow in the Division of Sleep and Circadian Disorders at Brigham and Women’s Hospital, said in a news release.
“Historically, Latinx populations have been underrepresented in research, especially genetic research,” she said. “But our findings highlight how important it is to look beyond European ancestry and European genetic risk factors to understand in what ways genetics may or may not contribute to their risk.”
Granot-Hershkovitz and colleagues examined data of 4,183 Latinx individuals from Cuban, Central American, Dominican, Mexican, Puerto Rican, and South American backgrounds with a mean age of 62.
The participants, who had European, African, and Amerindian genetic ancestries, received cognitive assessments after an average of seven years since their first assessment. Because many of them were too young to have developed Alzheimer’s and related dementias, the researchers examined related conditions such as significant cognitive decline and mild cognitive impairment, which can be precursors of dementia, while controlling for variables such as age and education.
The researchers found that ApoE4 was linked to the risk of cognitive decline in Latinx populations, especially for Cubans who had the lowest proportion of Amerindian ancestry compared to those with other backgrounds. They then found that a greater proportion of Amerindian genetic ancestry may protect against the risk of cognitive decline which accompanies ApoE4.
Lifestyle and environmental factors ranging from smoking and nutrition to sleep and air pollution may also play a role, the researchers noted, and future studies with older Latino populations that account for these factors is needed to tease out the associations.
Meanwhile, the study as well as past research focusing on Latino populations may help researchers better understand how APOE is linked to Alzheimer’s and related dementias in diverse populations, the scientists wrote, which can advance “the development of personalized risk prediction and strategies to address Latinos’ health disparities in neurodegenerative aging and disorders.”
“Latinx populations should know that they are represented in this area of genetic research now,” Granot-Hershkovitz said. “It’s not easy to participate in a research study, but there are revelatory findings from this amazing dataset, and hopefully there will be more in the future. This brings us a step further in addressing Latinx health disparities.”
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