Urban residents with more greenery within 100 metres of their homes have a lower risk of developing dementia over time. This is the finding of a new study from Stockholm University and Karolinska Institute, which followed nearly 3,000 older adults for 16 years. Published in the journal Alzheimer’s & Dementia, the study highlights the importance of greenspace in the immediate surroundings of the home for sustainable urban planning that supports brain health.
The study results show that more greenery in the immediate residential environment is associated with a 20 per cent lower risk of developing dementia over time.
“This is nature that forms part of the everyday home environment. Such environments may be particularly important when we spend more time at home.”
The researchers mapped the amount of vegetation around participants’ homes and monitored their cognitive health and the development of dementia over time through repeated assessments. The association was strongest for greenery in the area closest to the home (within 100 m) and weaker for greenery further away. The link between greenery and lower dementia risk was also more pronounced among women.
“This highlights the immediate environmental surroundings of the home as an important piece in creating conditions that support brain health and healthy ageing,” says Cecilia Stenfors, Associate Professor of Psychology, research leader at Stockholm University and first author of the study.
By measuring individuals’ residential environments and cognitive health in detail over a long period, the study provides new data and a stronger evidence base for sustainable urban planning that supports brain health throughout life.
The importance of greenspace in urban planning
The study provides further support for preserving and enhancing greenspace in residential and urban environments. Trees, green residential courtyards, gardens, parks, and vegetation along streets and walking routes offer many benefits, even when access to larger nature areas may be limited.
Previous and ongoing research points to several possible ways in which natural environments and greenery can support aspects of health that promote brain health throughout life and into older age.
“Natural environments and greenery can support psychological restoration, reduce stress and enhance feelings of well-being. Our studies have also found that more greenspace in the immediate residential environment is associated with better sleep and mental health, life satisfaction, and lower use of antidepressant prescription medication.”
Green environments can also influence our behaviour and encourage time outdoors, physical activity, including active mobility, and social contact and connectedness. At the same time, different types of greenspace provide many other ecosystem services, including mitigation of urban environmental hazards like traffic noise, air pollution and heat, climate change mitigation, and supporting biodiversity.
“Brain health needs to be considered when we plan and develop our cities and residential environments. Greenspace around our homes can be a shared resource for public health, climate adaptation and biodiversity,” says Cecilia Stenfors. “This means both protecting existing vegetation and creating green environments that are accessible and usable for people with different needs and abilities.”
About the study
The study included 2,993 people aged 60 years or over from the population-based SNAC-K study in Stockholm. During 16 years of follow-up, 477 participants developed dementia.
The amount of vegetation within 100, 250 and 500 metres of participants’ homes was measured annually using satellite imagery and geographic information systems. The researchers took into account factors including age, education, socioeconomic circumstances, lifestyle, air pollution, traffic noise and proximity to water.