Minerva Carrasquillo, assistant professor of neuroscience at Mayo Clinic Florida, right, and Dr. Nilufer Ertekin-Taner, neurologist and professor of neuroscience at Mayo Clinic Florida, left, were lead researchers on the Mayo Clinic's Alzheimer's study. Credit: Photo courtesy of Mayo Clinic

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A recent Mayo Clinic study points to potential breakthroughs in diagnosing Alzheimer’s disease through blood tests. 

While the study was conducted in Florida, local health care providers say it has far-reaching implications for the diagnosis and treatment of the disease in people of color. The study drew blood samples from 420 Black seniors; 151 of them had already been diagnosed with Alzheimer’s and 269 had been diagnosed as “cognitively impaired.”

The study surveyed Black patients because they have the highest risk of contracting Alzheimer’s, but the findings have implications for diagnosing the disease in patients of all backgrounds. 

Black people are twice as likely as whites to develop dementia, according to recent data from the National Institutes of Health. Yet, they are 35 percent less likely than the white population to be diagnosed with Alzheimer’s disease, which is the most common cause of dementia.  

“The reason is, they either don’t have access to medical care or are less likely to see a doctor,” said Minerva Carrasquillo, an assistant professor of neuroscience at Mayo Clinic Florida.

Blood tests could offer a cheaper and easier alternative to current options for diagnosing Alzheimer’s disease, she said.

Dr. Shauna Yuan, a neurologist at M Health Fairview in St. Louis Park, is all too familiar with the challenges of treating Alzheimer’s patients of color. One of the biggest hurdles in treating patients is getting information about care through to their caregivers and families, she said. 

There are several barriers to receiving cultural-specific care for Alzheimer’s patients from communities of color, she said. Those include: patients often have limited resources, they rely on an adult child or family member as their caregiver, and caregivers are frequently stretched thin with their other responsibilities. 

“I’ve had patients who come to their visits and are accompanied by a caregiver who has brought their kids along,” Yuan said. “The kids come along and are playing with the chair and the caregiver gets distracted, or has to leave the meeting. Then I don’t know if all the information gets through.” 

Yuan instructs Alzheimer’s patients to go on a walk once a day, but if caregivers are working a full-time job and raising children, the comparatively simple treatment can become a low priority.

Yuan often picks up on these difficulties as she’s giving instructions in her exam room.

“I can tell from their facial expression that this is something hard to do,” she said. “I don’t see it all the time, but I can tell when it happens.” 

Dementia is not a normal sign of aging

Dementia is a general term used to describe conditions causing a person’s cognitive decline in areas like memory and decision making. Alzhiemer’s disease is the most common cause of dementia. It’s characterized by a steady cognitive and bodily decline.

Little is known about what causes Alzheimer’s. The disease is genetic, and people with comorbidities such as chronic diabetes and high blood pressure are more likely to be diagnosed with the disease. It’s unknown if the comorbidities cause Alzheimer’s.

People of color are more likely to have these comorbidities, which may help explain why they’re at a higher risk of contracting the disease, said Jordan Lewis, an associate director of the Memory Keepers Medical Discovery Team at the University of Minnesota. Alzheimer’s is a terminal illness with no cure. Some medications that help treat early symptoms are available, and researchers are currently testing antibodies to kill the amyloid plaque buildup in the brain that causes the disease.

The most accurate screening for Alzheimer’s disease requires expensive, invasive medical procedures like a positron emission tomography scan, also known as a PET scan. Similar to an MRI, a PET scan is an imaging test that uses radioactive technology to detect amyloid plaques in the brain, which cause Alzheimer’s. The procedure, which can be covered by insurance, can cost between $2,000 to $10,000. 

Alzheimer’s can also be diagnosed by drawing spinal fluid with a needle, which can cause pain and cost about $1,000. 

Another reason for underdiagnosis of the disease in some communities of color is cultural attitudes toward dementia.

“Some people believe dementia is a normal consequence of aging,” Carrasquillo said. “It is not. It is a disease.”

Manka Nkimbeng, left, leads the Immigrant Memory Collaborative. Neurologist Shauna Yuan, right, treats patients with dementia at M Health Fairview. Credit: Photo collage by Ben Hovland | Sahan Journal

Manka Nkimbeng, an assistant professor at the University of Minnesota’s School of Public Health, leads the Immigrant Memory Collaborative, a project that seeks to improve African immigrants’ understanding and treatment of dementia.

The Immigrant Memory Collaborative held six community conversations with two dozen African immigrants in the Twin Cities area in order to gauge their understanding of dementia. The majority of attendees  were Liberian American. The project also surveyed about 150 African immigrants across the country about their attitudes toward and understanding of dementia.  

The project found that throughout their lives, most participants had identified memory loss in older people they knew, but didn’t learn about dementia until after immigrating to the United States. 

“African immigrants don’t recognize dementia as a medical problem,” Nkimbeng said. “To many, dementia is a normal problem of older age. Or, they would attribute it to other causes like spiritual causes, witchcraft, or thinking the person has gone crazy.” 

When people believe signs of dementia are a normal part of aging, they are less likely to seek medical care during the early stages of a disease like Alzheimer’s, Carrasquillo said. 

Getting people to understand that dementia is not a natural pattern of aging is the first step to strengthening community education about dementia, Nkimbeng said. 

Many immigrants distrust medical care for a variety of reasons, Nkimbeng said, including personal experiences with racism in medical settings. Many also don’t have the health insurance or the income to access quality care easily, she added. 

The Immigrant Memory Collaborative is hoping to launch a pilot project this summer to educate the African immigrant community about dementia. 

Accurate blood tests to screen Alzheimer’s could be around the corner

Alzheimer’s can only be diagnosed with 100 percent accuracy by examining a patient’s brain after death. Spinal tap and PET scan screening methods are the next most accurate way to diagnose at more than 90 percent. Blood tests are less accurate, but are currently used in clinics to help the patient determine whether to then get the more accurate PET scan or spinal tap. 

In the Mayo Clinic’s Florida study, researchers analyzed an array of different molecules in the blood plasma of patients who had Alzheimer’s. When they used that process they found six RNA molecules within plasma, that improved the diagnosis  accuracy by 8 percent. When adding information about these six RNA molecules in plasma combined with the patient’s sex, age and their genetic status of a known Alzheimer’s risk gene, APOE, the diagnosis accuracy reached 77 percent.

“​​Our hope is that by looking at molecules in plasma, we can get a high diagnostic accuracy,” said Carrasquillo, one of the study’s lead researchers. 

Carrasquillo said that in the most optimistic scenario, within five years a blood test could be as accurate in detecting Alzhiemer’s as a PET scan and spinal tap. 

If that happens, it would mark a significant shift in the equitable treatment of the disease, according to Carrasquillo and other researchers. Even though the disease is terminal, early diagnosis means people can take medication to ease the symptoms, Lewis said.

At the very least, Lewis said, an early diagnosis can help patients and their families better prepare for end of life services, such as creating a will. 

“It can give some people a peace of mind,” he said, “and caregivers now know what to expect.” 

Updated May 3 at noon with additional information about how the Mayo Clinic conducted the Alzheimer’s study.

Joey Peters

Joey Peters is a reporter for Sahan Journal. His work has appeared in Reuters, Public Radio International, Columbia Journalism Review, KFAI Radio, the Pioneer Press, City Pages, MinnPost and more. He previously...