Mexican-Americans show signs of Alzheimer's 10 years earlier than others, study says

Sid O'Bryant is committed to the study of Alzheimer's among Latinos through his work at the University of North Texas Health Science Center in Fort Worth.

But some discouraged him from fulfilling that mission.

"The funny thing for me, when I got into this work 15 years ago, I actually had a very prominent scientist tell me I shouldn’t go into studying Alzheimer’s among Latinos because the Latino population doesn’t like to be involved in research," O'Bryant said. "But you really can’t say that, because no one’s tried."

O'Bryant would not be deterred. In 2012, when he and his team of researchers began to study Alzheimer's among primarily Mexican-Americans, they found that, on average, Mexican-Americans develop cognitive loss and Alzheimer's nearly a decade before non-Hispanics do.

"That’s a real big problem, because it impacts quality of life, years worked, how these people are helping contribute to their families," O'Bryant said.

In 2016, his group set out to study the next question: Why?

In September 2017, a $12 million grant from the National Institutes of Health made a larger-scale study possible. In the next five years, the team will study 1,000 Mexican-Americans from North Texas and 1,000 non-Hispanic whites. By the end of the five-year grant, O'Bryant's team will have seen each research participant twice to understand how different biological causes relate to Alzheimer's across different ethnicities.

Each participant, who must be at least 50 or older, will receive an MRI, an interview, cognitive testing and blood work at both visits.

According to UNTHSC, the number of Hispanics in whom Alzheimer’s is diagnosed in the U.S. is expected to grow by more than 800 percent, reaching 1 million by 2060. However, Hispanics make up less than 1 percent of participants in clinical trials involving Alzheimer’s.

Through the study by O'Bryant's team, research has found that vascular issues and the primary gene for Alzheimer’s disease risks, APOE4, is more common among non-Hispanic whites and less common among Mexican-Americans, O'Bryant said.

However, Mexican-Americans have higher rates of depression and metabolic dysfunctions, such as diabetes.

O'Bryant said these findings are helpful because one of the goals of the study is to improve how genetic information about a person's illnesses is being used to diagnose or treat them. This is known as precision medicine.

"If we can say a person is at risk for memory loss because of depression, then we can use targeted antidepressants to treat their memory loss," O'Bryant said. "Same thing with diabetes. It’s a precision medicine approach to understand how the environment, and the social-cultural — but also the biological — mechanisms may be different among Mexican-Americans."

That means that because those two risk factors — diabetes and depression — are largely treatable, it may be possible to prevent memory loss, or at least delay it. But access to health care is another barrier that prevents early treatment.

That's why O'Bryant considers this to be a unique community study. He said the data he collects on each research participant goes back to the person's health care provider to promote better care. He said most Mexican-Americans rely on primary care physicians for their needs, and that's where Alzheimer's often goes underdiagnosed.

"We have found diabetes in so many people who didn’t know they had diabetes," O'Bryant said. "We found depression in people whose primary care doctors had no idea. So we give it all back so that it benefits the research participants."

O'Bryant has been developing a blood test for years that looks for specific biomarkers of Alzheimer's. Part of the current study includes testing the accuracy of that blood test among the 1,000 Mexican-Americans. The goal, O'Bryant said, is to provide that blood test to primary care doctors, community health clinics and Federally Qualified Health Centers.

So if a patient 65 or older comes in with complaints of memory issues, physicians can run the test and then will have an objective medical observation to refer the patient for a dementia exam.

"Majority of patients will not have dementia and Alzheimer’s disease," he said. "It’s only about 12 percent of those 65 and above. The big need for this is so that you can tell almost 80 percent of the patients who walk through the door who are concerned that they’re fine. Stop worrying."

For one of the researchers, Raul Vintimilla, being able to give back to the Hispanic community was important. Vintimilla is from Ecuador and moved to Fort Worth in 1995 after completing his hospital residency in Cuenca. After he got his master's degree in public health from UNTHSC, he was often told he had the qualifications but not the research experience when he applied for research positions.

But in 2012, when O'Bryant was starting this research, Vintimilla was hired, in part, because he spoke Spanish, and he worked his way up from scheduling research trials to performing neuropsychological testing.

"Just being Hispanic, I need to give back and do the best I can by the community," Vintimilla said. "They are the reason I’m here and working in this kind of research."

As in many communities, the stigma around mental health issues in Hispanic communities is especially prevalent. However, O'Bryant said he's grateful to the Hispanic communities in North Texas who have agreed to participate in the study and take the time to do so. His own experience in losing his grandmother to the disease is part of what motivates him to help others.

"It’s frustrating for me with the mental health stigma and the stigma around the word ‘dementia,’ because this is brain disease," O'Bryant said. "What we are in life is our memories. That’s what makes us who we are, our experiences. And that’s what Alzheimer’s steals. It steals our core essence."

This story was originally published June 19, 2018 at 6:00 AM with the headline "Mexican-Americans show signs of Alzheimer's 10 years earlier than others, study says."