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Healthy aging is an environmental, social and political phenomenon, according to a new study which used epidemiological modelling to analyse the impact of different individual and systemic factors on brain ageing.
The authors call for public health strategies expand beyond lifestyle prescriptions to address the structural inequalities and governance deficits that shape population-wide ageing disparities.
“Our biological age reflects the world we live in,” says corresponding author Dr Agustin Ibanez, from the Global Brain Health Institute (GBHI) at Ireland’s Trinity College Dublin and Latin American Brain Health Institute (BrainLat). “Exposure to toxic air, political instability and inequality affect society but also shapes our health. We need to stop thinking of brain health as a purely individual responsibility.”
Ibanez and the international team assessed the impact of the “exposome” – the combined physical and social exposures experienced by an individual throughout their life – on accelerated ageing.
They did this by introducing a new measure of accelerated ageing called “biobehavioral age gaps” (BBAGs).
This is the difference between a person’s actual age and the age predicted from protective factors – such as health, cognition, functional ability, education – and risk factors such as cardiometabolic conditions, sex, and visual and hearing impairments.
The analysis of almost 162,000 participants from national surveys of health and ageing found that “environmental and political conditions leave measurable fingerprints across 40 countries, revealing a clear gradient of accelerated ageing from Africa to Latin America, Asia, and Europe,” says first author Dr Hernan Hernandez, a neuroscientist at BrainLat.
Co-corresponding author Dr Sandra Baez, a neuroscientist and neuropsychologist at GBHI, adds: “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.”
The results indicate that individuals from lower-income countries have greater accelerated ageing compared to those from high-income countries, capturing “the disproportionate burden of accelerated aging in disadvantaged populations,” write the authors of the paper.
Several kinds of adverse exposures were linked to faster ageing. This includes 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.
For example, they say that “despite advances in gender equality, women still face disproportionate disadvantages owing to caregiving roles, economic inequalities and healthcare access, potentially exacerbating accelerated ageing”.
They add that sociopolitical factors can impact health through chronic stress pathways and that “political polarisation, governance failures and institutional instability impact health through policy-driven resource allocation, social cohesion and healthcare system stability, increasing ageing disparities”.
“By identifying which factors have the greatest associations with accelerating or delaying aging, interventions can be tailored to optimise healthy ageing outcomes,” write the authors.
Psychiatrist and co-first author Dr Hernando Santamaria-Garcia, from GBHI at the University of California, San Francisco, says: “Governments, international organisations, and public health leaders must urgently act to reshape environments, from reducing air pollution to strengthening democratic institutions.”
“Cognition, functional ability, education, well-being, physical activity, sensory impairments and cardiometabolic conditions can be addressed through lifestyle changes, multicomponent interventions and public health policies,” the authors write.
“Less modifiable factors – such as air quality and sociopolitical conditions including inequality and political representation – require addressing systemic disparities. Incorporating country-level exposome data into global surveillance could help identify structural drivers of accelerated aging and guide equitable resource allocation.”
They emphasise the findings are “intended to support inclusive and equitable policy responses that mitigate structural vulnerabilities – not to label or penalise countries or communities”.
The research has been published in in Nature Medicine.