A long-term study of older Australians has revealed that where you live may play a powerful role in how your brain ages.
ACU's Professor Ester Cerin's new research has found that living in walkable, green, and well-connected neighbourhoods – especially those with access to public transport, commercial services, and blue or green spaces – may help protect against memory and cognitive decline.
Professor Cerin, one of the world's leading researchers on the environmental and psychosocial determinants of cognitive health in ageing populations, led the research in collaboration with the Centre for Healthy Brain Aging (CHeBA) at UNSW Sydney.
The findings, published in Alzheimer's and Dementia, come from the Sydney Memory and Ageing Study (MAS), one of Australia's largest and longest-running studies of ageing and brain health.
More than 1000 adults aged 70 and older were followed for nearly 14 years to investigate the factors that predict cognitive stability, decline, and even improvement.
Participants living in more densely populated, greener areas with better access to services were less likely to develop dementia.
However, those exposed to higher levels of air pollution, particularly fine particulate matter (PM2.5), were more likely to experience cognitive decline.
"What's exciting about this research is that it confirms that the environment you live in isn't just a backdrop to healthy aging—it's a key ingredient," Professor Cerin, lead author and founder of the International Cognitive Health and the Environment Network (ICHEN), said.
"Supportive neighbourhoods that encourage activity, reduce stress, and offer better air quality appear to help protect the ageing brain.
"This study builds on similar findings from other research contributing to ICHEN on the impact of environmental exposures on cognition and is particularly important as it is based on rigorous cognitive assessments across a long period of time."
Access to public transport, parkland and coastal or blue spaces were also linked to a greater chance of recovering from mild cognitive impairment, a precursor to dementia.
Dr Annabel Matison, post-doctoral Research fellow at CHeBA said the research shows the potential for urban planning and environmental policy to shape brain health outcomes at a population level.
"This is a hopeful message. Even in later life, living in the right environment can offer a second chance for cognitive improvement – not just delay deterioration," she said.
Professor Perminder Sachdev and Professor Henry Brodaty, co-directors of CHeBA and the study's founding investigators, said the results were the culmination of nearly two decades of work.
"When we began MAS in 2005, we aimed to understand why some people maintain cognitive function while others decline," Professor Sachdev said. "This new analysis gives us deeper insight into how the built and natural environments play a role."
Following the success of the original MAS, a new follow-up study was launched in 2023, to explore these environmental effects in a new generation of older Australians.
MAS2 will reflect societal changes such as better education, improved health care access, and greater cultural diversity.
With more than 200 scientific publications already generated from the study, this latest research adds weight to the growing recognition that healthy ageing is not just about genes or lifestyle, it's also about where you live.
