The Brain Ages at Different Rates – Depending on the Social and Physical Environment

According to a study published in Nature Medicine involving the University of Surrey, countries with greater inequalities – whether in terms of economics, pollution or disease – have higher brain ages.

Factors that Make the Brain Age Faster

The rate at which the brain ages can vary greatly from person to person, leading to a discrepancy between the estimated biological age of the brain and chronological age (the actual number of years a person has lived). This difference can be influenced by various factors, e.g. environmental factors such as pollution and social factors such as income or health inequalities, especially in older people and people with dementia.

Until now, it was unclear how these combined factors can either accelerate or delay brain ageing in different geographical populations. In the study, an international team of researchers developed ways to measure brain aging using advanced brain clocks based on deep learning of brain networks. The study included a diverse data set of 5,306 participants from 15 countries, including Latin America and the Caribbean (LAC) and other countries. By analyzing functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) data, the researchers quantified age differences in the brains of healthy individuals and those with neurodegenerative diseases such as mild cognitive impairment (MCI), Alzheimer’s disease and frontotemporal lobe degeneration (FTLD). Dr. Daniel Abasolo, co-author of the study and Head of the Centre for Biomedical Engineering at the University of Surrey, said: “Our research shows that in countries where inequality is greater, people’s brains tend to age faster, particularly in the areas of the brain that are most affected by ageing. We found that factors such as socioeconomic inequality, air pollution and the impact of disease play a major role in this faster ageing process, especially in poorer countries.” Participants with a dementia diagnosis, particularly Alzheimer’s disease, showed the greatest age differences in the brain.

Identifying People at Risk of Neurodegenerative Diseases

The study also revealed gender differences in brain aging, with women in Latin American and Caribbean countries showing greater brain age differences, particularly in participants with Alzheimer’s disease. These differences were associated with biological sex and gender inequalities in health and social conditions. These findings highlight the role of environmental and social factors in brain health inequalities. The results of this study have profound implications for neuroscience and brain health, particularly for understanding the interaction between macrofactors (exposome) and those mechanisms underlying brain aging in different populations in healthy aging and dementia.

The study’s approach, which incorporates multiple dimensions of diversity into brain health research, provides a new framework for personalized medicine. This framework could be crucial for identifying individuals at risk for neurodegenerative diseases and for developing targeted interventions to mitigate these risks. Furthermore, the results of the study emphasize the importance of considering the biological embeddedness of environmental and social factors in public health policy. Policy makers can reduce age differences in the brain and promote healthier ageing in the population by addressing issues such as socioeconomic inequality and environmental pollution.