A new study highlights how societal inequality influences brain health, revealing that higher levels of inequality are linked to reduced brain volume and connectivity. Researchers call for targeted interventions to address these disparities, especially in underrepresented populations.
A team of international researchers led by Trinity College Dublin has uncovered a compelling link between societal inequality and changes in brain health associated with aging and dementia. The study, published today in Nature Aging, suggests that structural inequalities, such as socioeconomic disparities measured by the GINI index, have a profound impact on brain structure and connectivity.
The research, driven by the Multipartner Consortium to Expand Dementia Research in Latin America (ReDLat), the Latin American Brain Health Institute (BrainLat), the Global Brain Health Institute (GBHI) at Trinity College Dublin and other global centers, scrutinized neuroimaging data from over 2,000 participants across the Americas. The findings reveal how societal factors become biologically embedded, specifically in regions critical for memory and cognitive function.
“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,” Agustina Legaz, first author from the ReDLat consortium, said in a news release.
The study found that individuals living in countries with higher levels of inequality exhibited reduced brain volume and disrupted connectivity, particularly in the temporo-posterior and cerebellar regions. These regions are essential for memory and cognitive function.
The effects of inequality were most pronounced in Latin America, where Latinos with Alzheimer’s disease showed the most significant neurodegeneration. This suggests that socioeconomic stressors exacerbate age-related cognitive declines in these populations.
The study underscores that these associations between inequality and brain health persist even after accounting for individual-level factors such as education, age, sex and cognitive ability. This indicates the independent and pervasive impact of macro-level factors on brain health.
“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,” added corresponding author Agustín Ibáñez, a professor in global brain health at Trinity College and director of BrainLat.
The study calls for a multi-level approach to brain health equity, exploring other macro-level exposome factors, such as democratic governance, air pollution, migration, climate change and access to green spaces. By identifying and addressing these region-specific modulators, future interventions could mitigate accelerated brain aging and reduce the dementia burden in disadvantaged communities.