Alzheimer’s disease prevalence in African Americans is nearly twice that found in White or European-ancestry groups residing in the United States. While social determinants such as healthcare disparities, educational inequality, diagnostic bias, and increased cardiovascular and metabolic comorbidities contribute to this disparity, the genetic architecture underlying AD risk in African Americans has remained elusive. Prior gene expression studies predominantly focused on mixed or European-ancestry cohorts, often marginalizing African American participants, thus limiting statistical power to identify population-specific molecular changes.

This new research addresses this glaring gap by analyzing post-mortem brain tissue from 207 African American donors—comprising 125 individuals with pathologically confirmed AD and 82 cognitively normal controls. The tissue originated from the prefrontal cortex, a brain region critically involved in higher-order cognition and severely impacted in Alzheimer’s pathology. By deploying cutting-edge gene expression profiling technologies, the researchers quantitatively assessed the activity of thousands of genes, uncovering a suite of differentially expressed genes, many of which had previously not been associated with AD.

Among the most striking discoveries was the elevated expression of ADAMTS2, a gene encoding an extracellular matrix metalloproteinase, found at approximately 1.5 times higher levels in AD brains compared to controls. This finding held robust statistical significance and was corroborated by analysis of an independent dataset derived from a larger sample of European-ancestry individuals, verifying that ADAMTS2 upregulation is a shared hallmark of Alzheimer’s pathology across ethnicities.

The convergence of ADAMTS2 as the top-ranked gene in both populations is unprecedented in AD genetic research. It implicates common biological mechanisms driving neurodegeneration, suggesting that despite diverse genetic backgrounds and environmental exposures, fundamental pathogenic pathways may be conserved. ADAMTS2’s role in remodeling the brain’s extracellular matrix could influence amyloid plaque deposition or synaptic integrity, positing it as a compelling target for therapeutic development.

Leading the study, Dr. Lindsay A. Farrer emphasized the significance of these cross-population findings: “The overlap in gene expression changes points towards universal biological processes in AD progression. This offers hope for developing treatments with broad efficacy while underscoring the importance of including diverse populations in genetic research to capture the full spectrum of disease biology.”

The implications of population-specific versus shared genetic risk factors are profound. While many AD risk variants exhibit varying frequencies or exclusive associations within different ancestries, identifying genes like ADAMTS2 that transcend these boundaries advances the field toward unified models of neurodegeneration. It also highlights the necessity of expanding genomic studies in underrepresented groups to ensure equitable biomedical advancements.

This extensive project was undertaken with specimens sourced from 14 NIH-funded Alzheimer’s Disease Research Centers nationwide, ensuring a robust and geographically diverse sample of African American brain tissue. The methodological rigor entailed pathologically verifying diagnosis and implementing sophisticated statistical models to control for confounding factors intrinsic to post-mortem transcriptional analyses, such as RNA integrity and cellular composition.

Further analyses revealed that the molecular pathways influenced by the identified gene set encompass not only extracellular matrix remodeling but also neuroinflammation, synaptic signaling, and metabolic regulation. These interconnected pathways offer a multi-layered framework for understanding how genetic perturbations contribute to the clinical manifestations of AD, potentially informing biomarker development and stratified therapeutic interventions.

This study is among the first to deliver a high-resolution portrait of gene expression disturbances in African American Alzheimer’s brains, setting a precedent for future inclusion of diverse populations in neuroscience research. It paves the way for investigating whether modulating ADAMTS2 expression or function can mitigate disease progression or cognitive decline.

Published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, the findings mark a critical stride toward enhancing the representation of African Americans in genetic studies and aspire to reduce health disparities. The work was meticulously supported by multiple NIH grants and state-level research awards, with strict adherence to ethical standards and discrete conflict of interest disclosures, underscoring the scientific integrity of the investigation.

Given the disproportionate impact of AD on African Americans and the complex interplay of genetic and social factors, this research underscores an urgent call for broader, more inclusive scientific inquiry. Such efforts promise not only to elucidate AD’s pathobiology more comprehensively but to unlock novel avenues for diagnosis and therapy that could benefit all affected populations.

In conclusion, the identification of ADAMTS2 as a consistently dysregulated gene across diverse ancestral groups invigorates the search for shared molecular triggers underpinning Alzheimer’s neurodegeneration. It invites a paradigm shift toward integrative genetic research that embraces population diversity as fundamental rather than auxiliary, ultimately contributing to equitable health outcomes and precision medicine in neurodegenerative diseases.

Subject of Research: Cells

Article Title: Novel differentially expressed genes and multiple biological pathways for Alzheimer’s disease identified in brain tissue from African American donors

News Publication Date: 8-Oct-2025

Web References: medrxiv.org/content/10.1101/2024.11.12.24317218v1

References: Published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, DOI: 10.1002/alz.70629

Keywords: Health and medicine

Lung cancer remains one of the most lethal malignancies globally, and its incidence has historically been associated with smoking and occupational exposures. However, recent advances in epidemiology and social medicine have expanded our understanding of cancer etiology, stressing the importance of social determinants of health. This study situates structural racism as a core determinant that shapes neighborhood environments—such as housing quality, pollution exposure, access to health services, and economic opportunity—thereby indirectly increasing vulnerability to carcinogenic risks and limiting preventive care access.

To elucidate the mechanisms connecting structural racism and lung cancer development, the authors employed a multidimensional approach, incorporating geospatial analyses, neighborhood socioeconomic indices, pollutant exposure assessments, and individual-level health data. They demonstrated that neighborhoods experiencing systemic disinvestment and segregation, disproportionately inhabited by racial and ethnic minorities, show elevated levels of environmental toxins, including particulate matter and hazardous air pollutants. These exposures have been consistently linked to inflammatory processes and mutagenic effects pivotal in carcinogenesis pathways.

The study’s findings underscore the cumulative burden of exposure driven by historical redlining and discriminatory housing policies that have confined minority populations to areas with poor environmental conditions. These conditions foster a chronic state of physiological stress and immune dysregulation, compounding cancer susceptibility. Moreover, the research identifies gaps in healthcare infrastructure within such neighborhoods, which impede early detection and effective treatment modalities, further exacerbating lung cancer outcomes.

Importantly, this work integrates the concept of “risk amplification,” where structural racism acts as a contextual amplifier, intensifying traditional risk factors such as tobacco use through psychosocial stress, targeted advertising, and limited cessation resources. The neighborhood’s socio-environmental milieu thereby functions not as a passive backdrop but as an active participant in cancer pathogenesis, shaping biological pathways through epigenetic modifications and chronic inflammation.

These novel insights have profound implications for public health policy and cancer prevention strategies. The authors argue for a paradigm shift toward addressing upstream social determinants in parallel with clinical interventions. This approach necessitates concerted action to dismantle systemic barriers, improve neighborhood environments, and deploy targeted health resources in marginalized communities. Such comprehensive policies could attenuate exposure to carcinogens, mitigate chronic stressors, and promote equitable access to preventive care, ultimately reducing racial disparities in lung cancer morbidity and mortality.

From a methodological perspective, the study leverages a rich dataset combining electronic health records with environmental monitoring and demographic mapping, enabling robust multilevel modeling of risk factors from molecular to societal scales. This interdisciplinary framework epitomizes the future of health disparities research, advocating for integration across epidemiology, environmental science, social science, and clinical medicine.

Critically, the research also confronts challenges surrounding measurement of structural racism and environmental injustice, highlighting the need for refined metrics that capture both historical policy impacts and current neighborhood realities. By advancing these analytical tools, future studies can more precisely identify causal pathways and evaluate the effectiveness of targeted interventions.

The role of environmental health as a mediator in lung cancer disparities further accentuates the urgency of regulatory policies addressing air quality and housing standards. The study’s data suggest that improving environmental conditions in historically marginalized neighborhoods could yield substantial reductions in cancer risk, underscoring environmental justice as a key dimension of health equity.

This research also invites a broader reflection on the biological embedding of social adversity, where systemic racism becomes biologically instantiated in disease susceptibility. Understanding this phenomenon challenges conventional biomedical models, encouraging integration of social determinants into clinical risk assessments, screening guidelines, and personalized medicine strategies.

Ultimately, the study calls on public health leaders, clinicians, policymakers, and communities to recognize and respond to the multilayered contributions of structural racism to lung cancer. Combating these disparities requires not only medical innovation but also transformative social change that reconfigures neighborhood environments and redistributes health-promoting resources.

In summation, the evidence presented in this landmark study transforms the discourse on lung cancer etiology by situating structural racism at the nexus of environmental exposures and health outcomes. It catalyzes a vital conversation about the systemic roots of cancer disparities, inspiring action to build healthier, more equitable communities.

Subject of Research: Structural racism’s impact on neighborhood conditions influencing lung cancer development

Article Title: [Not specified in the provided content]

Web References: doi:10.1001/jamanetworkopen.2025.18481

Keywords: Lung cancer, Risk factors, Ethnicity, Public health, Adults, Environmental health, Environmental illness