Understanding the Root Causes of Cognitive Decline in Disadvantaged Neighborhoods

Tanisha Hill-Jarrett, PhD

Despite Caucasian individuals making up the majority of people in the United States, evidence has shown that African American and Hispanics are at high risk of Alzheimer disease (AD). When they are diagnosed, African Americans and Hispanics are typically diagnosed in later stages of the disease, when they are more cognitively and physically impaired–and therefore in need of more medical care. Black women, existing at the intersection of both marginalized race and gender, may be at acute risk; however, the mechanisms underlying cognitive impairment remain poorly understood.

Led by Tanisha Hill-Jarrett, PhD, a study presented at the 2024 American Academy of Neurology (AAN) Annual Meeting, held April 13-18, in Denver, Colorado, examined the association of neighborhood disadvantage and subjective cognitive functioning among Black women. In total, 20,768 participants, aged 55 and older, from the Black Women’s Health Study completed 6 subjective cognitive function questions. Using area deprivation index (ADI), the multivariable odds ratio for poor compared with good subjective cognitive function among Black women at the highest vs the lowest quintile of ADI was 1.21 (95% CI, 1.02-1.42), but this association was attenuated by adjustment for participant education (OR, 1.07; 95% CI, 0.9-1.27).

At the meeting, Hill-Jarrett, a neuropsychologist and assistant professor of neurology at the University of California, San Francisco Memory and Aging Center, sat down with NeurologyLive® to provide an overview of her study and the reasons behind it. She spoke on the need to improve access to healthy food and resources for Black women in disadvantaged communities to ultimately improve long-term cognitive trajectory. Additionally, she spoke on the significance of the effect of education, and why this should be an area that is more heavily stressed going forward.

NeurologyLive: Why was this a topic of concern for research?

Tanisha Hill-Jarrett, PhD: Neighborhoods are important social determinants of health. It's particularly important when we're looking at diseases and disorders of aging, because oftentimes, people are aging within the context of a given neighborhood. I was specifically interested in looking at this in relation to Black women’s lived experience. I think it's an understudied area and also, the neighborhood may create unique exposures that may put Black women disproportionately at risk for Alzheimer disease. What we know currently is that there's disparities across both race as well as sex/gender, such that Black Americans have higher risk as well as rates of Alzheimer disease. We know that women also have higher prevalence rates of Alzheimer disease. When we break that down across race and gender, we actually see that Black women specifically have the highest prevalence. And this was data, I think, from 2014, but even when they extrapolated it to 2016, those disparities persist. The thought is that Black women existing at the intersections of marginalized race, as well as gender may be experiencing unique social exposures, those things being structural racism and sexism, in this context.

What are some of the major neighborhood disadvantages that are top of mind?

We used a composite measure called the area deprivation index. Work has been done with that [outcome] since the early 2000s, I believe, and even more recently by Amy Kind, MD, PhD and her colleagues using the Neighborhood Atlas. Basically, it's a composite of 17 census level variables that look across domains of education, housing, household composition, as well as employment and poverty measures. Things like how many people are below the poverty threshold? What’s the proportion of people in a given region that have a certain level of education or lower levels of education? Those sorts of things. It all goes into this composite index, and then we looked at that in relation to subjective cognitive functioning among Black women in particular.

How much does education play a factor into cognitive decline in this patient population?

In the study, we looked at the associations between neighborhood disadvantage and subjective cognitive functioning. We used data from Black Woman's Health Study, encompassing close to 21,000 Black women, and we put them into different quintiles of disadvantage. People in the first quintile have lower levels of neighborhood disadvantage people in the fifth quintile have the highest. What we saw was that disadvantage was associated with subjective cognitive decline. More people in the more disadvantaged neighborhoods reported more cognitive concerns.

When we include education in the model, it attenuated that association. I think that's a really important and key finding. Intervening on an individual education level, but also at a community level, designing interventions that improve literacy and improve education and access to education, may attenuate those negative impacts of neighborhood. There is an interesting relationship between neighborhood as well as individual factors like education. I'm not saying that neighborhood isn't important, because I think investing in neighborhoods and the people that have always resided in that neighborhood is also very important. It's a complicated situation, but focusing on education, as well as neighborhood level interventions are important.

What are some of the major changes you’d like to see from a policy level?

Yes, I think access to healthy foods [is critical]. If you look particularly within disadvantaged neighborhoods, sometimes they don't even have grocery stores, or they have to travel a significant distance to have access to healthy foods. In addition, I think access to green space, making people have options for like walking, etc. Green space does that, it gives people opportunities for exercise. That's important, but also the way that we educate the community is also important.

As a clinician doing community engaged work, going into these environments and tailoring information in a way that's culturally relevant and sensitive to the populations that are most impacted, is also important. It's about how you deliver the message, and also how you structure the research arguments as well. It's largely a structural and systemic issue instead of placing the blame on the individual and saying, why aren't you eating healthy? Because we know that diet could potentially impact your cognitive aging, and ultimately, your cognitive health outcome. It should be “Why don't they have access to these foods to eat healthy? And what do we need to do to change the system so that this is an option for them?

How do we properly conduct research in disadvantaged communities without disrespecting individuals or wasting their time?

It's all about the approach. Even if you're interested in doing research with the ultimate goal of benefiting these communities, you can’t be extractive. As part of the community engagement team that I'm involved with at the memory aging center, a lot of what we're doing is focused primarily on education and making sure that the information is out there in a way that salient and relevant for the populations that are most impacted. We're not “OK, here's a presentation outcome, do our research study.” There's a huge history of mistrust and for understandable reasons with how Black Americans have been treated in the medical system, as well as in research studies. Acknowledging the harms, acknowledging the mistrust, getting a better understanding of the potential barriers to participation, the potential barriers to coming to the clinic, [is important]. Sometimes people live in neighborhood where there are no clinics, and so the onus is on us as clinicians and researchers to structure things in a way that's conducive for these things to benefit these communities that need it the most.

Transcript edited for clarity.

REFERENCE
1. Hill-Jarrett T, Buto P, Glymour MM, et al. The association between neighborhood disadvantage and subjective cognitive functioning among Black women. Presented at: 2024 AAN Annual Meeting; April 13-18; Denver, CO. ABSTRACT 003191