Neighborhoods Could Hold the Secret to Slowing Brain Aging

The Impact of Neighborhood Environments on Cognitive Health

A recent study conducted by researchers from the Center for Healthy Brain Aging (CHeBA) at UNSW Sydney and the Australian Catholic University (ACU) has revealed that living in walkable, green, and well-connected neighborhoods can play a significant role in protecting against memory and cognitive decline. The research highlights how access to public transport, commercial services, and blue or green spaces can contribute to better brain health as people age.

The findings, published in Alzheimer's and Dementia, stem from the Sydney Memory and Aging Study (MAS), one of Australia’s most extensive and long-running investigations into aging and brain health. Over 1,000 adults aged 70 and older were followed for nearly 14 years to examine factors that influence cognitive stability, decline, and even improvement. The results suggest that individuals residing in densely populated, greener areas with greater access to essential services are less likely to develop dementia. On the flip side, those exposed to higher levels of air pollution—particularly fine particulate matter (PM2.5)—were more prone to cognitive decline.

“This research is exciting because it shows that the environment you live in isn’t just a backdrop to healthy aging—it’s a key ingredient,” said Professor Ester Cerin. “Supportive neighborhoods that encourage physical activity, reduce stress, and offer better air quality seem to help protect the aging brain. This study aligns with similar findings from other research and is particularly important due to its rigorous cognitive assessments over an extended period.”

Access to public transport, parkland, and coastal or blue spaces was also associated with a higher likelihood of recovering from mild cognitive impairment, which is often a precursor to dementia. Dr. Annabel Matison emphasized the hopeful message this brings: “Even in later life, living in the right environment can offer a second chance for cognitive improvement—not just delay deterioration.”

The research underscores the potential for urban planning and environmental policy to influence brain health outcomes at a population level. It suggests that thoughtful city design can have tangible benefits for cognitive function and overall well-being.

Professor Perminder Sachdev and Professor Henry Brodaty, Co-Directors of CHeBA and founding investigators of the Sydney Memory and Aging Study, highlighted the significance of the findings. They noted that the results represent the culmination of nearly two decades of work. When the MAS study began in 2005, the goal was to understand why some individuals maintain cognitive function while others experience decline. This new analysis provides deeper insights into how both the built and natural environments affect cognitive health.

In response to the success of the original MAS, a follow-up study called MAS2 was launched in 2023. This new initiative aims to explore the effects of environmental factors on a new generation of older Australians. MAS2 will take into account societal changes such as improved education, better healthcare access, and increased cultural diversity.

“The MAS2 cohort will allow us to investigate how different life experiences and environments shape aging in the 21st century,” said Prof. Brodaty.

With over 200 scientific publications already generated from the study, this latest research adds to the growing body of evidence that healthy aging is not solely determined by genes or lifestyle choices. It also emphasizes the importance of where individuals live and the surrounding environment.

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.