Short Wave - The Importance Of Diversifying Alzheimer's Research

Episode Date: March 11, 2021

Alzheimer's disease affects more than 6 million Americans and a disproportionate number are Black. NPR science correspondent Jon Hamilton explains why Black Americans may be at higher risk, and how diversifying Alzheimer's research could lead to a better understanding of the disease in Black Americans, and new treatments for everyone. Email the show at [e-mail] pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Hey, everybody. Emily Kwong here. Today, we are talking about Alzheimer's disease, which impacts more than 6 million Americans. And a disproportionate number are black Americans. So here to talk about that with me is NPRS John Hamilton, who covers brain science. Hey, John. Hey, Emily. So, John, you've reported on Alzheimer's for a long time now.

why is it such a problem for black Americans? When it comes to Alzheimer's, black Americans are facing this sort of trifecta of adversity. First, they're more likely than white Americans to get Alzheimer's and other forms of dementia. Second, if they do get it, they're more likely to have trouble accessing quality care. And third, scientists still know very little about how Alzheimer's may be different in people with African ancestry. That's because so far, research has focused largely on white people. Got it. Okay. So what's going on in Alzheimer's research to address this? Okay, I want to play you something here.

All right. Help me count it down in five. This is a walk to end Alzheimer's event. It was held in Cleveland, pre-COVID, of course. It attracted a lot of Black Americans, and it also attracted some Alzheimer's researchers from Case Western Reserve University. One of them was a research associate named Leah Cummings. She was there specifically to recruit people for a study of genes involved in memory. loss. This tells you about our study that we're doing at Case Western. We're looking for our families, minorities, and people with early onset. We discovered one gene that links to memory loss and we're looking for more. And it was working. A few attendees signed up that day. A few more said they'd think

about it. So would you say that more research institutions are making a serious effort to reach out to black Americans? Yeah. The National Institute on Aging, which is part of the National Institutes of Health, has made diversifying Alzheimer's research a priority. And you see efforts like the one in Cleveland, also happening in Chicago, Los Angeles, Baltimore. So it looks like change really is happening. So today on the show, the importance of diversifying Alzheimer's research. And how a better understanding of this disease in Black Americans could lead to new treatments for everyone.

So, John, let's talk about what Alzheimer's disease is and how it's related to other forms of dementia. Right. So dementia is an overarching term that refers to thinking and memory problems from lots of causes, including a stroke or head injury. Alzheimer's is far and away the most common cause of dementia, at least in later life. And it refers to this specific process where these toxic plaques and tangles build up in the brain and eventually start killing neurons. Those are the brain cells we use to think and remember. Yeah. And for black Americans, how much greater is their risk of development? developing Alzheimer's or some other form of dementia. Some studies show that the risk is twice as high as it is for a white American, though the exact amount still kind of in question. And by the way, there's also some evidence that Latinx people also have a higher risk, and Asian Americans appear to have a lower risk than white Americans.

Okay. And do scientists know why there are such huge disparities? Not fully. Some of the difference probably has to do with known risk factors for Alzheimer's, so health problems like heart disease, high blood pressure, diabetes, obesity, all of these increase a person's risk for Alzheimer's. And these risk factors are more common in black Americans than they are in white Americans. There's also at least one genetic risk factor.

Okay. People who have one or two copies of a gene called APOE4 are more likely to develop Alzheimer's, and the APOE4 gene appears to be more common in people of African ancestry. But scientists really don't understand Alzheimer's very well in anyone. They've been testing all of these Alzheimer's drugs for decades, and really nothing has worked. So researchers still don't know whether all of these risk factors put together can fully explain why Alzheimer's is so much more common in Black Americans. Yeah, John, that's really tough to hear. I mean, you mentioned health care earlier, you know, that Black Americans have less access to care for loved ones with Alzheimer's.

What do we know about that? Just a couple of weeks ago, the Alzheimer's Association released a report on race, ethnicity, and Alzheimer's. And I talked with brain scientist Maria Carrillo, who is now the chief science officer there. Here's part of what she told me about what they learned from a survey of people who were caring for a friend or family member with Alzheimer's. Among non-white caregivers, half say they've faced discrimination when navigating through the health care system, with a top concern being the providing. Vitis don't even listen to what they're saying, perhaps because of their race, color, or ethnicity. Hmm. That's really frustrating. Yeah. And not surprisingly, black Americans were the most likely to report discrimination.

Okay. So we've talked about risk. We've talked about care. Let's talk about research. So as scientists are trying to find treatments, what can be done to make sure that black Americans are included in that research? Several things. They can change. the racial and ethnic composition of the people who do research. Black researchers are more likely to have ties within black communities and are more likely to make sure that studies are inclusive. Researchers can also change the racial and ethnic composition of the people who participate in research studies. And they can focus on questions about why Alzheimer's appears to act differently in people of different races. Yeah. I mean, these are really good goals to have,

of course, but are researchers getting any closer to achieving them? I've seen some encouraging science, especially when it comes to diversifying scientific studies. So, for example, a couple of years ago, researchers formed a group called the African Ancestry Neuroscience Research Initiative. I spoke to one of the brain scientists involved, Dr. Kafweid Zrasa. He's a psychiatrist and a professor at Duke University. He told me he joined the effort when he realized that his own ancestors, who came from West Africa, had been excluded from genetic studies of brain disorders. It was clearly and immediately evident to me how much of a problem this was, right? Because for me, as one who does what we call basic research, in other words, I take the genes that are found in human gene studies, and then I study them in model organisms, in other words, things like mice or rats and understand how it changes how their brain works. It meant that I was studying genes that were specifically related to illness in folks of European ancestry. Which would mean that Kaffi Zerasa was only studying the genes of a narrow segment of people,

which sounds pretty messed up if you're trying to figure out the genetic story of how Alzheimer's affects all people. Like, what is the scientific justification for this approach? Years ago, the logic was that it would be easier to find genes responsible for brain disorders in people of European descent. The reason is that they tend to be very similar genetically to one another. The genes of people of African ancestry vary a lot more. Now, technology has made genetic sequencing so widely available that you can easily study all kinds of people. And scientifically, you should because people with different ancestries can have genetic differences that affect their risk for diseases like Alzheimer's. Absolutely.

And have scientists learned anything new about Alzheimer's disease from studying it in black Americans? Maybe. You know that gene APOE4 that increases a person's risk of developing Alzheimer's? especially if you inherit two copies, one from each of your parents. So the gene is more common among black Americans, but it may be less risky for them. Some other genetic factors seems to protect people of African ancestry from the bad effects of APOE4. I spoke with Dr. Daniel Weinberger. He's a scientist at the Lieber Institute in Baltimore, and he's also part of the African

Ancestry Neuroscience Research Initiative. Here's what he told me about APOE4. If you inherit the risk form of that gene from both of your parents and you're of European ancestry, that increases your likelihood of manifesting Alzheimer's disease later in life about 20-fold. If you're of African ancestry, the risk from inheriting that gene from both your parents is about a fourth of what it is if you're of European ancestry. So if scientists could figure out what the protective mechanism, is they might be able to develop a drug that would help protect all people who have at least one copy of the APOE4 gene. And that is, by the way, tens of millions of people in the U.S.

alone. Well, that sounds really promising, but it's going to take a lot more research, right? That also broadens who's being included in that research. It will. Truly diversifying the groups of people in research studies is really challenging, and scientists know they can't do it on their own. So the African Ancestry Project, for example, has involved people like Reverend Alvin Hathaway. He's the pastor of Union Baptist Church in Baltimore. He told me one challenge facing scientists is that a lot of black Americans are pretty skeptical about this kind of research.

You know, clearly, when you begin to talk about the brain, you begin to talk about the genomic data set, immediately within the community, that triggers all kinds of suspicions. It triggers a lot of suspicions because there has been arguments that the Caucasian brain is different from the brain of people of African descent. And one of the amazing revelations that I found was that when you actually look at brain matter tissue, you can't discern the difference. Right. Scientists propped up really racist thinking for a long time.

And you're saying the legacy of that lives on. Yes, it does. So, John, how do researchers with the African Ancestry Project and other groups navigate that? The Alzheimer's Association did a survey a few months ago that found that one in five Black Americans would actually feel insulted if a doctor even suggested a cognitive assessment to detect Alzheimer's. So Science and Medicine has a lot of work to do to build trust with Black Americans and other minority groups. I talked about what that might take with a scientist named Lisa Barnes. She's a professor and also a cognitive neuropsychologist at the Rush Alzheimer's Disease Center in Chicago. She told me she often hears the same comment when she approaches groups that have been marginalized about doing a research study,

especially one that may take years to complete. These researchers come in and they, you know, collect all these data and then we never hear from you again. So we also give back, you know, so we, you know, We make sure that we go back to the community and update them on what we're finding. We get their advice about how we're interpreting the data. So we try to really make it a partnership between us and the community. And I think that that goes a long way in building trust and having them stay with us for the long haul. Well, Don, it looks like efforts are heading in the right direction, at least, to be so much more inclusive.

And we look forward to having you on our show again to talk about how these efforts are going. I'm looking forward to it. And let's hope it's sooner rather than later. Yeah. All right. Well, this episode was produced by Britt Hansen, back checked by Burley McCoy and edited by Giselle Grayson. The audio engineer for this episode was Alex Drewenskis. I'm Emily Kwong. Thanks for listening to Shortwave from NPR. On NPR's, consider this podcast. We help you make sense of one big story in the news, every day, like how to combat disinformation and conspiracy theories, which pose a real threat to democracy,

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