A groundbreaking international study of 161,981 participants across 40 countries published in Nature
Medicine recently reveals that air pollution, social inequality, and weak democratic institutions substantially accelerate ageing. The collaborative study involves leading researchers from the Global Brain Health Institute at Trinity College Dublin.
The research introduces a global exposome framework (the study of how environmental exposures — physical, social, political — influence health and disease) and its impact on bio-behavioral age gaps (BBAGs), a novel measure of accelerated ageing. BBAGs are the difference between a person’s actual age and the age-predicted from their health, cognition, education, functionality, and risk factors like cardiometabolic health or sensory impairments.
This study — led by a multinational team from Latin America, Africa, Europe, Asia, and North America — analysed environmental, social, and political factors and their impact on brain ageing using advanced artificial intelligence and epidemiological modelling. The results show that where you live — your exposome — can age you several years faster, increasing the risk for cognitive and functional decline.
“Our biological age reflects the world we live in. Exposure to toxic air, political instability, and inequality, of course, affect society, but also shapes our health. We need to stop thinking of brain health as a purely individual responsibility and consider a more ecological and neurosyndemic framework”, said Agustin Ibanez, corresponding author of the study and researcher at the Global Brain Health Institute (GBHI) at Trinity College Dublin and Latin American Brain Health Institute (BrainLat).
The findings land at a critical time: With democracy in retreat across the globe, air pollution, and wealth gaps widening, these data present the first evidence that combined structural exposures beyond individual lifestyle are deeply embedded in our ageing process. In an age of rising populism, environmental degradation, and global displacement, understanding how environments age our brains is a scientific, political, ethical, and health imperative, said the authors.
Dr Hernan Hernandez, Latin American Brain Health Institute (BrainLat) and first author of the study, said: “This is not a metaphor: Environmental and political conditions leave measurable fingerprints across 40 countries, revealing a clear gradient of accelerated aging from Africa to Latin America, Asia, and Europe.”
Using computational tools, researchers developed the biobehavioral age gap (BBAG), a biological marker that compares predicted age to chronological age.
The BBAGs closely matched people’s actual ages, but many showed delayed or accelerated ageing beyond expectations.
Then the researchers used these gaps to examine patterns across different world regions and the types of exposures that might speed-up ageing. Europe had the healthiest ageing in comparison with other regions, while Egypt and South Africa showed the fastest ageing. People in Asia and Latin America were in the middle. Within
Europe, eastern and southern countries showed more rapid ageing. Globally, faster ageing was strongly linked to lower national income levels.
Several types of exposures were linked to faster ageing: Physical factors such as poor air quality; social factors, including economic inequality, gender inequality, and migration; and sociopolitical factors, such as lack of political representation, limited party freedom, restricted voting rights, unfair elections, and weak democracies. Importantly, higher BBAGs were associated with real-world consequences: They predicted future declines in both cognitive abilities and daily functioning. People with larger age gaps were likelier to show significant losses in these areas over time.
Sandra Baez, co-corresponding author and Atlantic Fellow for Equity in Brain Health at GBHI, Trinity College, said: “Whether a person ages in a healthy or accelerated way is shaped not only by individual choices or biology, but also by their physical, social, and political environments, and these effects vary widely between countries.”
This study redefines healthy ageing as an environmental, social, and political phenomenon. Public health strategies must expand beyond lifestyle prescriptions to address structural inequalities and governance deficits.
Hernando Santamaria-Garcia, co-first author and an Atlantic Fellow at GBHI, University of California, San Francisco, said: “Governments, international organisations, and public health leaders must urgently act to reshape environments, from reducing air pollution to strengthening democratic institutions.
“To promote healthy ageing and reduce dementia risk worldwide, we must intervene upstream, where inequality is produced, where politics shape lives, and where environments silently erode healthy ageing.”
