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Raising the Voice: A Comment on Race and Ethnic Disparities in Alzheimer’s Disease Clinical Research

Alzheimer's Disease clinical research has faced a significant challenge for a long time in achieving diverse racial or ethnic representation in clinical trials. Many of these issues are rooted in deeper structural problems that leave some populations apart from the scope of science. While much work remains to be done to address this subject, there is a growing demand for more representative clinical trial data.

By: Maria Alejandra Tangarife, MSc


By: Evelyn Gutiérrez, ChemE

Scientific Manager

By: Margarita Venegas, MS

Clinical Psychologist

Alzheimer’s Disease (AD) research faces a significant challenge in achieving diverse ethnic and racial representation in clinical trials, evidenced by lower enrollment and retention rates among Hispanic and Black individuals compared to non-Hispanic Whites.1 This disparity raises concerns about access, cost, and medication effectiveness post-market release, yet public awareness still needs to be improved  in the clinical trial settings. This text explores this topic by setting grounds on the distribution of recruited participants in AD clinical trials, discussing problems in the recruitment strategies in populations other than Whites, and offering options that clinical trial staff can consider for designing the eligibility criteria and reducing the screen and retention failure for these populations.

In a recent review, Rutten-Jacobs and colleagues analyzed the study population distribution within the F-Hoffmann-La Roche database, focusing on global neuroscience-related clinical trials.2 Data were extracted from participants in 47 countries and revealed that, for AD clinical trials, the global race distribution was composed of 82.2% Whites, 8.8% Asians, 1.0% Blacks, 2.0% American Indian or Alaska Native, less than 0% Native Hawaiian or Pacific Islander, 0.2% multiple races, and 5.7% classified as Other/Unknown. The global ethnicity distribution followed a similar pattern, with 81.6% of the population categorized as Not Hispanic or Latino and 16.9% as Hispanic or Latino. Comparatively, other studies have indicated a mere 2% representation of non-Hispanic Blacks among AD clinical trial enrollments, while Hispanic/Latinos constituted approximately 4.4% or less in North American site studies.2,3 Non-Hispanic White individuals were most predominant in clinical trials; nevertheless, non-Hispanic Blacks and Hispanic/Latinos are more likely than other race/ethnic groups to be impacted by AD.4

 Therefore, why are individuals from diverse racial and ethnic backgrounds not adequately represented in AD Clinical Trials? The issue stems from a broader problem in the generalizability of biomedical research within patients.5 The impact of a drug or treatment on individuals in clinical trials demands the consideration of biological and sociocultural factors, as the disease manifests through the interplay of these variables.5,6 Even though it is correct to highlight that the differential factors from the population are not solely rooted in biology, the lived experiences of structural racism, lower socioeconomic status, and limited education, which are associated with specific biological risk factors,  have received less attention from the research community.5 These findings clarify a critical lack of awareness concerning race and ethnicity in clinical trials, that consequently fail to address the Consideration of the Principle of Justice under 45 CFR part 46.6,7 This principle argues that human subjects research often serves the interests of the privileged and powerful, perpetuating economic, racial, religious, sexual, gender, and cultural biases, therefore, to achieve objectivity on research questions and experimental designs, researchers and sponsors must reflect on experience and background in their members to consider what are the burdens of participation in their studies and be open to the populations affected by any given disease, without selectivity or  constraint.7 Conversely, this approach is not free of the structural difficulties every study faces in resolving the persistent problem of underrepresentation in AD clinical trials among distinct communities. A critical reevaluation of the current research framework may address this issue in research practices.

To comprehend why underrepresented racial and ethnic communities are less willing to participate in clinical trials, have less consistent recruitment strategies, and often are ineligible after initial screenings,8,9 researchers are required to explore the various factors that contribute to this failure to enroll. These factors include socioeconomic status, literacy, acculturation, stigma associated with cognitive decline, discrimination, neighborhood health metrics, and beliefs about dementia within these populations.9–11 The multifaceted nature of the differences emphasizes a need for a more inclusive approach when conducting clinical trials.12 Small changes could have a positive impact on the screening and enrollment processes. For example, reflecting on the effect of the inclusion or exclusion criteria in the non-Hispanic Black and Hispanic/Latino individuals and including the effect of culture -meaning viewing individuals as part of cultural currents that are themselves historically, geographically, and socially situated13,14– for screening 14 may allow a broader interpretation of results based on these differences.9

Implementing a more comprehensive strategy in clinical trial study design and recruitment is critical to mitigate the disproportionate enrollment rates. The challenges in AD exploration extend beyond mere methodology, encompassing broader implications of AD knowledge and accessibility. Various strategies have been proposed for clinical trials. Raman and colleagues9 offer actionable recommendations applicable across settings, involving the creation of prescreening databases, standardized data capture for sociocultural factors, and a minimal data set for recruitment. Additional proposed measures include quantifying recruitment efforts and costs, introducing differential reimbursement based on participant demographics, selecting diverse study teams, establishing comprehensive recruitment and retention plans that prioritize diversity, adjusting eligibility criteria for underrepresented groups, and conducting data collection, particularly cognitive testing, in non-English languages. Emphasizing media opportunities emerges as a strategy to increase caregiver and patient awareness and encourage inclusivity in study participation.

In conclusion, researchers are more aware of the seemingly poor participation of racial and ethnic groups other than Whites and non-Hispanics respectively.9 The need to foster diversity will allow us to understand how the broader population is affected by AD, but more importantly will help us look for more personalized options for the treatment of the disease.12 While much work remains to be done to address this issue within the Alzheimer’s Disease Research community, there is a growing demand for more representative clinical trial data. The commitment to inclusivity and diversity in AD research is needed for advancing our understanding and treatment of this disease. Once we have the opportunity to explore innovative treatments, this will eventually unlock new perspectives and ways of thinking, allowing research to boldly go where no trial has gone before, this means into unexplored territories that will not only push the boundaries of our knowledge but also propel us toward a better future of collective well-being—a journey reminiscent of the bold spirit Star Trek – which I am fan of.



    1. Leggins B, Jackson A, Hart DM, et al. Perceptions about Dementia Clinical Trials. Alzheimers Dement. 2023;19(S21):e074906. doi:10.1002/alz.074906
    2. Rutten-Jacobs L, McIver T, Reyes A, et al. Racial and ethnic diversity in global neuroscience clinical trials. Contemp Clin Trials Commun. 2024;37:101255. doi:10.1016/j.conctc.2024.101255
    3. Savold J, Cole M, Thorpe Jr. RJ. Barriers and solutions to Alzheimer’s disease clinical trial participation for Black Americans. Alzheimers Dement Transl Res Clin Interv. 2023;9(3):e12402. doi:10.1002/trc2.12402
    4. 2021 Alzheimer’s disease facts and figures. Alzheimers Dement. 2021;17(3):327-406. doi:10.1002/alz.12328
    5. Langbaum JB, Zissimopoulos J, Au R, et al. Recommendations to address key recruitment challenges of Alzheimer’s disease clinical trials. Alzheimers Dement. 2023;19(2):696-707. doi:10.1002/alz.12737
    6. Protections (OHRP) O for HR. Consideration of the Principle of Justice 45 CFR part 46. Published July 28, 2021. Accessed April 29, 2024. https://www.hhs.gov/ohrp/sachrp-committee/recommendations/attachment-a-consideration-of-the-principle-of-justice-45-cfr-46.html
    7. Ortiz F, Fitten LJ, Cummings JL, Hwang S, Fonseca M. Neuropsychiatric and Behavioral Symptoms in a Community Sample of Hispanics With Alzheimer’s Disease. Am J Alzheimers Dis Other Demen. 2006;21(4):263-273. doi:10.1177/1533317506289350
    8. C. Arévalo-Flechas L, Acton G, I. Escamilla M, N. Bonner P, L. Lewis S. Latino Alzheimer’s caregivers: what is important to them? Dr Donna Blancero PMROL and DDLS, ed. J Manag Psychol. 2014;29(6):661-684. doi:10.1108/JMP-11-2012-0357
    9. Raman R, Quiroz YT, Langford O, et al. Disparities by Race and Ethnicity Among Adults Recruited for a Preclinical Alzheimer Disease Trial. JAMA Netw Open. 2021;4(7):e2114364. doi:10.1001/jamanetworkopen.2021.14364
    10. Aranda MP, Marquez DX, Gallagher‐Thompson D, et al. A call to address structural barriers to Hispanic/Latino representation in clinical trials on Alzheimer’s disease and related dementias: A micro‐meso‐macro perspective. Alzheimers Dement Transl Res Clin Interv. 2023;9(2):e12389. doi:10.1002/trc2.12389
    11. Gill TM, Zang EX, Murphy TE, et al. Association Between Neighborhood Disadvantage and Functional Well-being in Community-Living Older Persons. JAMA Intern Med. 2021;181(10):1297-1304. doi:10.1001/jamainternmed.2021.4260
    12. Zuelsdorff M, Larson JL, Hunt JFV, et al. The Area Deprivation Index: A novel tool for harmonizable risk assessment in Alzheimer’s disease research. Alzheimers Dement Transl Res Clin Interv. 2020;6(1):e12039. doi:10.1002/trc2.12039
    13. Ardila A. Cultural Values Underlying Psychometric Cognitive Testing. Neuropsychol Rev. 2005;15(4):185-195. doi:10.1007/s11065-005-9180-y
    14. Fernández AL, Abe J. Bias in cross-cultural neuropsychological testing: problems and possible solutions. Cult Brain. 2018;6(1):1-35. doi:10.1007/s40167-017-0050-2

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