Approved Research

Green space exposure influences cognitive and brain health via multiple pathways

Lay summary

People's living space is changing as more cities are being built. Over 50% of the population is living in urban cities worldwide. In the UK, 83% of the population lives in urban areas, with only 23% of the areas covered by grassland and woodland. This is the opposite of the rising evidence that more green space exposure benefits people's mental and physical health. Therefore, it is key to examine and clarify the potential protective role of green space on health.

Past studies identified the psychological restoration effect on the mental health of green space exposure. A limited number of studies also found more green space exposure associated with better cognitive function and healthier brains, with varied methodologies and populations. However, it is still unclear if green space is associated with some specific cognitive functions (e.g., working memory, attention, etc) or brain health features (e.g., resting-state functional connectivity) that indicate cognitive status. Additionally, a few pathways of green space on cognitive health have been proposed in the past, but not examined with consistent methodologies and samples. In the current study, we will examine the benefit of green space in a multidomain analysis of cognitive and neuroimaging measures, and multiple pathways behind this relationship, in order to provide a comprehensive picture of whether and how green space influences cognitive health.

Firstly, we will examine the association between green space exposure and comprehensive analysis of neuroimaging data (e.g., grey matter, white matter, functional connectivity under resting state) and multiple cognitive measures. Secondly, we will examine the potential pathways proposed by previous research, including physical activity engagement, air pollution, and mental well-being by testing multiple mediation models. The results will provide insight into the environmental building for the urban city and the application of green space for intervention and therapy.

Scope extension:

We would like to examine the hypothesis that more exposure to green space in the living environment promotes cognition and multidomain brain health in middle-to-older aged adults. We would also like to examine potential mechanisms behind this relationship. Previous research has proposed multiple pathways of a green space effect on cognitive health, including promoting physical activity engagement, better psychological well-being, or less pollution. While previous research focused on separate aspects of the benefits of green spaces, we will testing multiple potential mediators of green space and cognition/brain association in the same study.

The new question, based on the extant literature, is whether hearing impairment is associated with level of physical activity and the extent to which access to local green space modifies the relationship between hearing impairment and physical activity.  As per our originally approved project we are also interested in whether the effects of access to green space and physical activity is associated with cognition in the hearing impaired.  This minor extension of our original project is based on several recent studies that have explored the relationship between hearing impairment and physical activity.

We only need permission to include two additional UK BioBank measures (fields 2247 (Hearing difficulty/problems) and 2257 (Hearing difficulty/problems with background noise)) to our analyses to test our novel question.