Green spaces reduce dementia risk, study finds

The World Health Organisation has defined public health as ‘the art and science of preventing disease, prolonging life and promoting health through the organised efforts of society’. Public health therefore extends beyond the provision of health services and includes the assessment and evaluation of neighbourhoods, communities and environments that may be pivotal to physically active ageing. Results suggested that globally, the poorer urban environments are high risk for older people’s mental health and these places often lack parks and green spaces. There is evidence that the level of activity and social participation may be greater with access to green spaces and therefore reduces health risks. Green spaces seem to have a role in preventing cognitive frailty, especially for more vulnerable older populations living in poorer urban environments.This is exactly where the impact of a recent study from the University of Georgia’s College of Public Health lies. The research highlights the significant impact of environmental factors on dementia risk. Led by Assistant Professor Suhang Song in the Department of Health Policy and Management, the meta-analysis revealed that exposure to air pollution and access to natural spaces, such as parks (green spaces) and bodies of water (blue spaces), can influence the likelihood of cognitive decline and dementia. "These numbers show that living in a dementia-friendly environment is important to delay or prevent cognitive decline and the onset of dementia,” Song said.Conducting the meta-analysis was important, as was taking several empirical studies to create a clearer picture about environmental risk, Song said. The research combined 54 studies in a systematic review and 21 in the meta-analysis, enabling researchers to quantify the impact of several factors. While past research has shown the association between environmental factors and dementia risk, Song said the contributions of some factors were worth noting.Living near major roadways was associated with a roughly 10% higher risk of dementia, and exposure to fine particulate matter in the air — something that is generated by vehicles and industrial emissions — was associated with a 9% increase in risk. Nitrous Oxide increased risk by 10%, and noise pollution was shown to increase risk by about 9%. Alternatively, some built environments help reduce the risk of cognitive decline. Green and blue spaces, which include built and natural parks as well as bodies of water, reduced risk by about 6%. Walkability in a community, as well as access to local amenities including food stores, community centres, and healthcare, also reduced risk."Based on these findings, we can suggest that people visit parks or forests more often and also live further from the major roads,” Song said. "Also, living in a community where there is more walkability, or being close to local amenities like bookstores, healthcare centres and more is helpful.” This data can help inform urban planning efforts moving forward to create more communities that foster cognitive health, Song said while observing that the biggest advantage of the paper is to quantify the association between certain factors and cognitive health. "This analysis can provide evidence for data-driven urban planning and support decision makers.”The systematic review and meta-analysis focused on studies using objectively measured environmental factors, which may reduce the bias associated with subjective measures such as perceptions of air quality or individual reports of greenspace and an area’s beauty. Song hopes this study will serve as a foundation for future research, encouraging researchers to prioritise objective measurements in investigating environmental influences on cognition and dementia risk.