A recent study published in *Nature Medicine*, led by researchers including Dr Daniel Abasolo from the University of Surrey, highlights how economic, pollution-related, or disease-based disparities correlate with accelerated brain ageing in different countries. The research indicates that the rate of brain ageing varies considerably from person to person, which can lead to discrepancies between the biological age of the brain and a person’s chronological age—the actual number of years lived. This variance is influenced by various factors, notably environmental pollutants and social issues such as income and health inequalities. These influences are particularly pronounced in elderly populations and those suffering from dementia, but until this study, the cumulative impact of these factors on brain ageing across various global populations was not well understood.
The team employed cutting-edge ‘brain clocks’, developed through deep learning techniques applied to brain network analysis, to assess brain ageing. Their methodology was tested on a comprehensive dataset encompassing 5,306 participants from 15 countries, including nations from Latin America, the Caribbean (LAC), and others outside of this region. By utilising functional magnetic resonance imaging (fMRI) and electroencephalography (EEG), the researchers were able to measure discrepancies in brain age among both healthy individuals and those with neurodegenerative conditions such as mild cognitive impairment (MCI), Alzheimer’s disease, and frontotemporal lobe degeneration (FTLD).
Dr Abasolo shared that the research demonstrated that higher levels of inequality in a country are linked to more rapid brain ageing, particularly in regions most susceptible to the ageing process. Factors such as socioeconomic inequality, air pollution, and prevalent diseases significantly contribute to this acceleration, with more pronounced effects observed in economically disadvantaged countries. Among those diagnosed with dementia, individuals with Alzheimer’s disease exhibited the most significant gaps in brain age. Additionally, the study revealed sex differences in brain ageing, with women in LAC countries showing more significant gaps, especially those affected by Alzheimer’s. These differences were attributed to biological sex and gender disparities in health and social circumstances. Notably, the findings could not be explained by variations in signal quality, demographic factors, or the methods used to acquire data.
These insights are critical for neuroscience and brain health, offering a deeper understanding of how broad environmental and social factors (collectively referred to as the exposome) interact with the biological processes of brain ageing across diverse populations, both in the context of healthy ageing and dementia. The approach taken in the study introduces a promising new framework for personalised medicine, which is essential for identifying individuals at increased risk of neurodegenerative diseases and crafting targeted interventions to mitigate these risks. Furthermore, the results underscore the importance of integrating the biological impacts of environmental and social factors into public health policies. By addressing issues like socioeconomic disparity and ecological pollution, policymakers have the potential to narrow brain age gaps and foster healthier ageing across different populations.
More information: Sebastian Moguilner et al, Brain clocks capture diversity and disparities in aging and dementia across geographically diverse populations, Nature Medicine. DOI: 10.1038/s41591-024-03209-x
Journal information: Nature Medicine Provided by University of Surrey
