A collaboration between researchers from the Center for Healthy Brain Aging (CHeBA) at UNSW Sydney and the Australian Catholic University (ACU) has found that living in walkable, green, and well-connected neighborhoods—especially those with access to public transport, commercial services, and blue or green spaces—may help protect against memory and cognitive decline.
The findings, published in Alzheimer’s and Dementia, come from the Sydney Memory and Aging Study (MAS), one of Australia’s largest and longest-running studies of aging and brain health. More than 1,000 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. Conversely, 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. Supportive neighborhoods that encourage activity, reduce stress, and offer better air quality appear to help protect the aging 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,” says Professor Ester Cerin.
Notably, 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.
“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,” says Dr. Annabel Matison.
The research underscores the potential for urban planning and environmental policy to shape brain health outcomes at a population level.
Professor Perminder Sachdev and Professor Henry Brodaty, Co-Directors of CHeBA and founding investigators of the Sydney Memory and Aging Study, 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. This new analysis gives us deeper insight into how the built and natural environments play a role,” Prof. Sachdev said.
Following the success of the original MAS, a new follow-up study was launched in 2023, aiming 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.
“The MAS2 cohort will allow us to investigate how different life experiences and environments shape aging in the 21st century,” Prof. Brodaty added.
With more than 200 scientific publications already generated from the study, this latest research adds weight to the growing recognition that healthy aging is not just about genes or lifestyle—it’s also about where you live.
More information:
Ester Cerin et al, Neighborhood environments and transition to cognitive states: Sydney Memory and Ageing Study, Alzheimer’s & Dementia (2025). DOI: 10.1002/alz.70569
Provided by
University of New South Wales
Citation:
Neighborhoods may hold the key to slowing cognitive decline (2025, August 7)
