Summary: A major international study reveals that accumulated social hardships across the lifespan — the social exposome — leave lasting marks on the brain. Adverse social exposures such as limited education, food insecurity, financial strain, and poor access to healthcare are associated with cognitive decline, increased mental health symptoms, reduced functional ability, and measurable changes in brain structure and connectivity.
These links appear both in cognitively healthy older adults and in people living with dementia, indicating that social adversity can become biologically embedded in brain networks over time. The results underscore the need for public health and policy strategies that begin early in life to reduce social inequalities and lower dementia risk decades later.
Key Facts
- Cumulative Risk: Lifelong exposure to social adversity predicts poorer cognition, altered brain networks, and worse mental health.
- Dementia Impact: In people with dementia, complex adverse exposomes — including food insecurity, financial insecurity, and limited healthcare access — are linked to worse symptoms and disrupted brain connectivity.
- Early Prevention: Policies and interventions in childhood and midlife that improve education, food security, and healthcare access can strengthen brain resilience and reduce dementia vulnerability.
Source: TCD
Lifetime social experiences shape identity — and they also shape brain health.
Everyday social conditions across life—childhood hardships, educational opportunities and quality, exposure to violence, work and family environments, and access to basic resources—can accumulate and influence how the brain develops, connects, and copes with age-related change. The new study, published in Nature Communications, introduces a comprehensive measure of the social exposome and shows how its cumulative burden is linked to cognitive, emotional, and neural outcomes.
The research defines an adverse social exposome as the combined lifetime exposure to factors like low education and its quality, adverse childhood experiences, food insecurity, financial stress and asset scarcity, poor access to healthcare, and traumatic events. Across multiple clinical and neuroimaging outcomes, higher exposome adversity was consistently associated with worse brain health.
Conducted by an international collaboration including the Global Brain Health Institute (GBHI) at Trinity College Dublin, the Multipartner Consortium to Expand Dementia Research in Latin America (ReDLat), and the Latin American Brain Health Institute (BrainLat), the work focuses on Latin America because structural inequality, educational disparities, and social determinants of health exert a particularly strong influence on brain health in the region.
The social exposome and brain health
The researchers developed and validated a multidimensional social exposome assessment covering 319 indicators across domains such as education quantity and quality, food insecurity, financial resources and assets, objective and subjective socioeconomic status, access to healthcare, childhood labor and experiences, traumatic events, and social relationships. They then evaluated these exposome scores in 2,211 people — including cognitively healthy controls and individuals with Alzheimer’s disease or frontotemporal lobar degeneration — recruited from six countries in Latin America.
Findings show a clear pattern: greater cumulative social adversity corresponded with larger impairments in cognition, daily functioning, mental health, and brain structure and connectivity. Different social and environmental factors at various life stages mapped onto multiple dimensions of brain health. Among cognitively healthy older adults, more adverse exposomes predicted poorer cognitive performance. Among people with dementia, complex exposome profiles — particularly food insecurity, financial strain, low socioeconomic status, and limited healthcare access — were associated with lower cognitive and functional performance, more neuropsychiatric symptoms, and measurable changes in brain anatomy and connectivity.
Crucially, it was the accumulation of exposures across the lifespan — not any single factor in isolation — that showed the strongest relationships with outcomes. These associations held across countries, demographic groups, dementia subtypes, and various imaging protocols, indicating robust links between lifetime social environments and brain health.
Overall, the results illustrate how compounded social adversity becomes biologically embedded in brain structure and function, and how a tailored, multidimensional exposome model can more precisely capture brain health outcomes related to aging and dementia risk.
Why prevention must begin early: implications for research and policy
Dementia prevention strategies that focus only on midlife risk factors like blood pressure or diabetes miss a major part of the picture. The foundations of brain health are laid in childhood and shaped throughout life. Policies that reduce food insecurity, improve education quality, expand access to healthcare, and create supportive social environments in early and midlife can build brain health capital with benefits that persist into old age.
The study authors note that a substantial share of dementia cases in regions such as Latin America is attributable to modifiable risk factors — estimates cited in the study point to 56% attributable to known modifiable risks like obesity, inactivity, and depression, compared with 46% globally. These figures are closely linked to dimensions of the social exposome and underscore how accumulated adversity elevates dementia vulnerability.
As Joaquín Migeot, neuroscientist and Atlantic Fellow at the Global Brain Health Institute, explains: “The interaction between modifiable risk factors and the social exposome offers a path toward developing precision dementia prevention agendas tailored to each individual’s social exposome and risk profile.”
Agustín Ibáñez, Professor in Brain Health at the Global Brain Health Institute and Director of BrainLat, emphasizes that the study documents “a systematic association of multidimensional social lifespan experiences on brain health outcomes,” calling for tailored models that incorporate the lifelong social environment into understanding how aging and dementia become biologically embedded.
About the study
This research moves beyond single-factor measures such as years of education or income. It integrates multidimensional, lifespan experiences into a single social exposome index that accounts for education quantity and quality, food insecurity, financial stress and assets, subjective and objective socioeconomic measures, access to healthcare, childhood labor and adverse events, and relationships. Across more than 2,200 participants in six Latin American countries — including cognitively healthy adults and people with Alzheimer’s disease or frontotemporal dementia — higher exposome adversity tracked with lower cognitive and functional ability, poorer mental health, and structural and functional alterations in brain networks sensitive to dementia.
About this social neuroscience and dementia research news
Author: Ciara O’Shea
Source: TCD
Contact: Ciara O’Shea – TCD
Image: The image is credited to Neuroscience News
Original Research: Open access. “Social exposome and brain health outcomes of dementia across Latin America” by Joaquín Migeot et al., Nature Communications
Abstract
Social exposome and brain health outcomes of dementia across Latin America
A multidimensional social exposome (MSE) — combined lifespan measures of education, food insecurity, financial status, access to healthcare, childhood experiences, and more — may shape dementia risk and brain health over the lifespan, particularly in underserved regions like Latin America. To date, the effects of MSE on brain health and dementia have been underexplored.
The study evaluated 2,211 individuals (controls, Alzheimer’s disease, and frontotemporal lobar degeneration) from a non-representative sample across six Latin American countries. Adverse exposomes were associated with poorer cognition in healthy aging. In dementia, more complex exposomes correlated with lower cognitive and functional performance, higher neuropsychiatric symptoms, and structural and connectivity alterations in frontal-temporal-limbic and cerebellar regions. Food insecurity, limited financial resources, subjective socioeconomic status, and poor healthcare access emerged as especially strong predictors. Cumulative exposome measures outperformed isolated factors in predicting clinical and cognitive profiles. Multiple sensitivity analyses confirmed the results, highlighting the need for personalized approaches that integrate MSE across the lifespan and prioritize prevention and interventions to reduce social disparities.