Why Native Americans are facing high rates of mental decline

Amna Nawaz:

It's estimated that around seven million Americans have Alzheimer's disease, a number that's expected to double by 2060. But researchers have found that some of the highest rates of cognitive impairment and dementia exist in a population that's long been one of the most difficult to study, Native Americans.

Stephanie Sy recently traveled to Seattle to understand why.

Dr. C. Dirk Keene, U.W. Medicine:

And so this is — this is a full-sized brain.

Stephanie Sy:

Inside this laboratory at U.W. Medicine in Seattle, scientists study brains hands on, both healthy and diseased.

Dr. C. Dirk Keene:

And so, in Alzheimer's disease, the brain atrophies. It starts to shrink.

Stephanie Sy:

Dr. Dirk Keene leads the lab, where more than 4,000 human brains are preserved for science.

Dr. C. Dirk Keene:

So this person may have Alzheimer's disease. They may have Lewy body dementia. They may have some tiny little strokes that we call microinfarcts, all contributing to their dementia.

Stephanie Sy:

Alzheimer's disease is marked by abnormal protein deposits in the brain. This lab houses one of the nation's leading Alzheimer's projects.

Dr. C. Dirk Keene:

When you look at — in the microscope, it's so cool, right?

Stephanie Sy:

The goal, to analyze brain tissue in hopes of unlocking new treatments and cures for the disease that is the leading cause of dementia among older adults.

Dr. C. Dirk Keene:

The greatest gift you can give to science, I think, is your brain. It's really the gift that keeps on giving.

Stephanie Sy:

The brain bank depends on brain donations, some of which have been stored and studied for more than 40 years. But there is a key gap. Among the thousands of brains in the repository, less than five have been donated from Native Americans.

Dr. C. Dirk Keene:

So the fact that we don't have very many Native American donor brains makes it a lot more difficult for us to understand what's happening before they die.

Stephanie Sy:

Native Americans have some of the highest risk factors for developing Alzheimer's. A 2024 NIH study found that 54 percent of older American Indians now have some degree of cognitive impairment, a significantly higher rate compared to the general population.

Cognitive impairment can be a precursor to dementia, including Alzheimer's disease.

Dr. Thomas Grabowski, U.W. Medicine:

There are a number of things that can lead to memory impairment besides Alzheimer's disease that are also prevalent in those communities.

Stephanie Sy:

Dr. Thomas Grabowski directs the University of Washington's Alzheimer's Disease Research Center.

Dr. Thomas Grabowski:

There's a high rate of cerebral vascular disease and diabetes. There's higher rates of post-traumatic stress disorder. There's higher rates of alcoholism. There's surprisingly high rates of traumatic brain injury. And all these factor in.

Stephanie Sy:

Why hasn't there been more research around this particular community, which has comorbidities for cognitive decline and Alzheimer's as well?

Dr. Thomas Grabowski:

It's a community or it's a collection of communities which are particularly wary, I would say, of some of the institutionalized scientific process in the United States. And so building trust with communities is harder and slower. It's a long process.

Stephanie Sy:

That process began nearly three years ago for 76-year-old Linda Holt, a Native American and former health director of the Suquamish Tribe.

Once a year, she makes a nearly two-hour trip that includes an early morning ferry ride from her home in Bremerton, Washington, to a U.W. hospital in downtown Seattle.

Woman:

All right, so the next test is going to be a memory test.

Stephanie Sy:

There, Holt is given a series of cognitive tests.

Woman:

And, earlier, I had read you a list of words. If you could tell me all of the words you remember from that list.

Linda Holt, Alzheimer’s Research Study Participant:

Face, velvet, church, daisy, red. Parachute.

Stephanie Sy:

She's enrolled in ongoing research now being conducted as part of a decades-long study into Alzheimer's by teams from the University of Washington and Washington State University.

Woman:

Now, can you please tell me the name of this animal?

Linda Holt:

Lion.

Woman:

This one?

Linda Holt:

Rhinoceros. Camel.

Stephanie Sy:

She signed up for the study despite her own reservations.

Linda Holt:

Native Americans are very hesitant about volunteering for these types of things. And that comes historically from studies that were involuntarily done on Native American people.

Stephanie Sy:

Across the country, 32,000 Americans participate in Alzheimer's research, but less than 250 participants identify as either American Indian or Alaska Native. The Seattle program is actively trying to recruit Native Americans and already has nearly 40 participants, with the goal of enrolling 100 in the next few years.

Cole Allick, Washington State University:

So, by 2050, we're going to have eight times the number of 85-year-olds in tribal communities.

Stephanie Sy:

Cole Allick is an assistant professor at Washington State University who grew up in North Dakota as part of the Turtle Mountain Chippewa Tribe.

Linda Holt:

How are you?

Cole Allick You look great. That smile's worth it.

(Laughter)

Stephanie Sy:

He says the program uses fellow Native Americans to not only help recruit participants like Holt into the study, but to guide them throughout the research process.

Cole Allick I would never do this by myself. If my mom or my siblings or my grandparents were ever to go to an appointment growing up, there was always someone with them.

Linda Holt:

It's kind of, I think, a bonding that is done between Natives. It's like, oh, where are you from? What's it like on the reservation where you grew up? And sharing that kind of information and getting to know that person has a big impact.

Dr. Thomas Grabowski:

It seems like your memory's doing pretty well.

Stephanie Sy:

While Holt isn't showing any signs of dementia or cognitive impairment, she says she's become an advocate for this research within her community.

Linda Holt:

How this disease impacts families just really interested me. As far as coming up with ways to prevent it, ways to help stop it once it develops, ways to cure it.

Erik Perrohe, Alzheimer’s Research Study Participant:

Face, velvet, church, daisy, red?

Stephanie Sy:

Sixty-seven-year-old Erik Perrohe also signed up for the study. His Native American heritage can be traced back to his mom, who he says began showing signs of cognitive decline near the end of her life.

Erik Perrohe:

I saw my mom decline, and that was very difficult.

Stephanie Sy:

A grant from the NIH funds this research. But earlier this year, as part of a larger effort by the Trump administration to slash federal spending, the program's funding was delayed. A few months later, their grant was renewed.

Erik Perrohe:

Well, I'm glad that the research is managing to continue despite all of the anti-science sentiment that is in this country.

Dr. Thomas Grabowski:

You might be asked at some point whether you are interested in ultimately letting us look at the brain.

Stephanie Sy:

While steady progress is being made, several hurdles still remain, especially when it comes to brain donation.

Linda Holt:

I have cultural issues with that. When you leave this world, you have to have your whole body to go.

Dr. Thomas Grabowski:

Yes.

So we devoted a lot of the last five years to just understanding how to transact a research relationship with participants like the ones that we interviewed today. What sorts of things are culturally acceptable to them? What sorts of ways can we reconcile how we do scientifically integral work with their norms?

Dr. C. Dirk Keene:

This person has lost a huge amount of their brain mass because of Alzheimer's disease.

Stephanie Sy:

Back at the brain bank, Dr. Keene says only actual brains can reveal the kind of ground truth needed to develop targeted treatments and preventions.

Dr. C. Dirk Keene:

Native Americans will have specific differences in what causes dementia, how susceptible they are to certain things, what drugs might work better or worse. We can only really know that once we have been able to study the brain tissue from those folks. And that's true for any community.

Stephanie Sy:

But researchers say the contributions Linda Holt has already made may be crucial for healing the next generation.

For the "PBS News Hour," I'm Stephanie Sy in Seattle.