Socioeconomic disparities linked to changes in brain structure associated with aging and dementia
Researchers at Trinity College Dublin have teamed up with international partners to investigate whether societal inequality impacts our brains. 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 that are associated with aging and dementia.
The study also sheds light on how societal inequities become biologically ingrained, especially in underrepresented populations throughout Latin America and the United States.
Findings
Researchers found that higher levels of inequality are associated with decreased brain volume and disrupted connectivity, particularly in the temporo-posterior and cerebellar regions, which are crucial for memory and cognitive function. These effects were more pronounced in Latin America, underscoring the unique vulnerability of Latin American populations to macro-level socioeconomic stressors.
The findings also revealed that Latinos with Alzheimer’s disease experience the most severe impacts, suggesting that environmental demands tied to structural inequality may worsen neurodegeneration in aging populations. Reduced brain volume and connectivity are often observed in patients with dementia and are linked to disease progression and severity.
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 one’s 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.”
Solutions
The study calls for a multi-level approach to brain health equity, exploring the biological embedding of various macro-level factors beyond socioeconomic inequality. These factors may include democratic governance, air pollution, migration, climate change, and access to green spaces. By identifying and addressing these region-specific modulators, targeted interventions could be developed to mitigate accelerated brain aging and reduce the dementia burden in disadvantaged communities.
