Landmark Population-Based Study Reveals the Prevalence of Vascular and Alzheimer's Dementias Disease Among American Indians

PASADENA, Calif., May 15, 2024 /PRNewswire/ -- Huntington Medical Research Institutes (HMRI), a pioneer in scientific research dedicated to unraveling diseases of the heart and brain, gains new insights into dementia among American Indians for the first time through a landmark study led by renowned epidemiologist Astrid Suchy-Dicey, PhD, Associate Professor, and Scientific Director, Clinical and Translational Neurosciences.

This is the first large, prospective, population-based study to estimate the prevalence of vascular and Alzheimer's dementias in American Indians, using a gold-standard method of cognitive determination consistent with protocols used by National Alzheimer's Coordinating Center Alzheimer's Disease Research Centers and as recommended by National Institute on Aging and Alzheimer's Association. This report, "Epidemiology and prevalence of dementia and Alzheimer's disease in American Indians: data from the Strong Heart Study," was published today in Alzheimer's and Dementia: The Journal of the Alzheimer's Association.

Until recently, the epidemiology of Alzheimer's disease and related dementias among American Indians and other Indigenous peoples has been critically underrepresented in mainstream dementia research. Disparities in socioeconomics, historical, and sociological factors increase risk, resulting in disparate prevalence and incidence of disease. American Indians endure a high prevalence of contributing comorbidities, such as hypertension, diabetes, and depression, exacerbated by relatively poorer access to socioeconomic resources. Suchy-Dicey cautions, "interpretation of race-based differences [in health disparities research] should be done with caution; such differences probably have more to do with social determinants than with biological differences."

Previous data using administrative and health records estimated dementia prevalence in American Indians and Alaska Natives as similar to that of non-Hispanic Whites. However, this prospectively conducted, population-based study detected higher prevalence -- with approximately half of American Indians over age 65 affected by some cognitive impairment, and approximately 10% with dementia.

These epidemiologic findings are thought to be an improvement on prior research because they are not limited by underreporting of cases in the clinical context. Records-based research may be prone to data or information bias, due to inadequate or late care, poor specialty access in rural regions, and poor cultural sensitivity in some contexts. It is estimated that up to 50% of those with dementia may be missing notations in their medical records, further increasing disparities for those who experience barriers to care, and compounding problems for research on racial-ethnic disparities using such data. Thus, prior studies that are not population-based, with prospectively collected, objective, and sensitive methods for case identification may represent underestimates of true prevalence and incidence in these populations. So far, the data in this report is the closest to gold-standard epidemiologic estimates of dementia prevalence for American Indians.

Additionally, this study reported novel findings that vascular brain injury was equally important to Alzheimer's disease in etiology, both as independent contributors but also with substantive overlap between them. This suggests a continued need for vascular prevention in this population, which may be lagging behind the majority population in reduction and prevention of cardiovascular disease (CVD) and cerebrovascular disease (CBVD). Future studies will investigate whether primary prevention of vascular disease could result in decreased prevalence and incidence of dementia in this population.

Finally, traumatic head injury was found to be a significant contributor among "other" impairments, perhaps representing acute cognitive changes. These findings echo prior research on blood biomarker findings, which detected higher prevalence of markers for neuronal remodeling in this population than expected. More follow-up is needed, but this may be an important factor to consider in future dementia research, especially in American Indians and other minoritized groups.

"Overall, our findings emphasize the importance of inclusive Alzheimer's disease and dementia research, representing all populations, and especially with data gathering that is sensitive and knowledgeable to that particular group," said Suchy-Dicey. "We hope these findings will be useful to clinicians and researchers, especially those interested in health disparities."

Suchy-Dicey collaborated with University of Washington School of Medicine colleagues Kimiko Domoto-Reilly, MD, Suman Jayadev, MD, Thomas J Grabowski, MD, and Kristoffer Rhodas, PhD, and with Dedra S. Buchwald, MD and Lonnie Nelson, PhD, of Washington State University. Data and participants are from the Strong Heart Study, and part of a growing body of work on Alzheimer's disease and vascular dementias in this otherwise critically-understudied population. This study has been funded in whole or in part with federal funds from the National Institutes of Health, including the National Heart, Lung, and Blood Institute and National Institute on Aging, including R01HL093086 (Buchwald), P50AG005136 (Grabowski), K01AG057821 (Suchy-Dicey).

More information: Astrid M. Suchy-Dicey et al, Epidemiology and prevalence of dementia and Alzheimer's disease in American Indians: data from the Strong Heart Study, Alzheimer's and Dementia: The Journal of the Alzheimer's Association (2024). https://doi.org/10.1002/alz.13849

About HMRI
Based in Pasadena, California, Huntington Medical Research Institutes (HMRI) is a pioneer in scientific research with a 70-year track record of groundbreaking discoveries that have changed the world – from seatbelts to lifesaving diagnostic technology like the MRI. Today, HRMI is laser-focused on biomedical research that investigates diseases of the heart and brain, and it is committed to inspiring and educating the next generation of scientists.

SOURCE Huntington Medical Research Institutes