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.