Researchers from Trinity College Dublin have collaborated with international partners to explore if societal inequality affects our brain. Their research paper is published in Nature Aging today, [Friday, December 27th] by an international team of researchers from the Multipartner Consortium to expand dementia research in Latin America (ReDLat), the Latin American Brain Health Institute (BrainLat), the GIobal Brain Health Institute (GBHI) at Trinity College Dublin, and other centres across the globe. The study reveals a direct link between structural inequality—such as socioeconomic disparities measured by a country-level index (GINI)—and changes in brain structure and connectivity associated with aging and dementia.
The study also sheds light on how societal inequities become biologically embedded, particularly in underrepresented populations across Latin America and the United States.
Key findings
1.Researchers found that higher levels of inequality are linked to reduced brain volume and disrupted connectivity, especially in temporo-posterior and cerebellar regions essential for memory and cognitive function. These effects were more pronounced in Latin America, highlighting the unique vulnerability of Latin American populations to macro-level socioeconomic stressors.
2.The findings also revealed that Latinos with Alzheimer’s disease experience the most severe impacts, suggesting that environmental demands linked to structural inequality may exacerbate neurodegeneration in aging populations. In contrast, the milder effects observed in frontotemporal lobar degeneration support the hypothesis of a more significant genetic influence in this condition. Reduced brain volume and connectivity are frequently observed in patients with dementia and are associated with disease progression and severity.
3. Notably, associations persisted even after accounting for individual factors such as education, age, sex, and cognitive ability, underscoring the independent role of macro-level factors in shaping brain health. Living in a context of aggregate inequality affects brain health regardless of your specific socioeconomic level, demonstrating the far-reaching consequences of societal disparities on the brain.
First author Agustina Legaz, PhD from the ReDLat consortium, said,
“Our findings emphasize the urgency of integrating not only individual social determinants of health into global brain health research but also macro-level exposome factors, such as social and physical variables. These findings pave the way for future studies exploring the biological mechanisms linking aggregate inequality to aging and neurodegeneration.”
Dr. Agustín Ibáñez, PhD, professor in global brain health at Trinity College, and director of BrainLat and corresponding author, added:
“This research highlights the critical role of structural inequality in shaping brain health. Considering dementia rates rise particularly in low- and middle-income countries, our findings emphasize the need for targeted interventions to address the root causes of brain health disparities, which appear to be specific to each region.”
The study calls for a multi-level approach to brain health equity, examining the biological embedding of other macro-level exposome factors beyond socioeconomic inequality. These may include variables such as democratic governance, air pollution, migration, climate change, and access to green spaces. Identifying and addressing these region-specific modulators could lead to targeted interventions that mitigate accelerated brain aging and reduce the dementia burden in disadvantaged communities.
You can read the paper ‘Structural inequality linked to brain volume and network dynamics in aging and dementia across the Americas’ at this link (when embargo has lifted) : https://doi.org/10.1038/s43587-024-00781-2
Dr Agustín Ibáñez, PhD,
Professor in Global Brain Health
Global Brain Health Institute (GBHI)
Trinity College
Tel: +353 830 103625
Ciara O’Shea
Research Communications Manager (Health Sciences)
Trinity Communications
Trinity College Dublin
COSHEA9@tcd.ie | 086 787 0746
Notes for the Editor
About the study
This research analyzed neuroimaging data from 2,135 participants, including healthy controls and individuals with Alzheimer’s disease and frontotemporal lobar degeneration, across six countries in Latin America (Argentina, Colombia, Chile, Peru, Mexico) and North America (United States). Using advanced imaging techniques to study brain volume and functional connectivity and the GINI index to measure macro-level socioeconomic inequality, the study offers one of the most comprehensive examinations of how structural inequalities influence brain health.
About the researchers
This study is a collaboration between the ReDLat consortium, the leading institution BrainLat at Universidad Adolfo Ibáñez, the Global Brain Health Institute at Trinity College Dublin, and other international centers. It was supported by grants from the National Institutes of Health (NIH), the Fogarty International Center, the National Institute on Aging (R01 AG057234, R01 AG075775, R01 AG021051, R01 AG083799, CARDS-NIH), the Alzheimer's Association (SG-20–725707), the Rainwater Charitable Foundation, the Bluefield Project to Cure FTD. Additional funding was provided by Chile’s National Research and Development Agency (ANID: Fondecyt 1210195 and 1210176 and 1220995, 15150012; ANID/PIA/ANILLOS ACT210096; FONDEF ID20I10152, ANID/FONDAP 15150012). The contents of this publication are solely the author’s responsibility and do not represent the official views of these institutions.
Contact information
For more information, please contact:
agustin.ibanez@gbhi.org ; agustinalegaz@gmail.com
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