Living near green space could prevent cognitive decline

New evidence has linked exposure to green space as a potential approach to improving overall cognitive function and helping to prevent dementia.

Cognitive function at middle age is a strong predictor of whether a person may develop dementia later in life. A new study from the Boston University School of Public Health (BUSPH) has found that increasing green space in residential areas could help improve cognition function in middle-aged women. Exposure to green space can also reduce depression, which is also a risk factor for dementia.

From 2014 to 2016, the researchers estimated residential green space and measured psychomotor speed, attention, learning, and working memory among 13,594 women aged 61.

Adjusting for age, race, and individual and neighborhood socioeconomic status, the experts found that green space exposure was associated with psychomotor speed and attention.

To understand the association between greenspace and cognitive function, air pollution and physical activity was also examined. The team was surprised to find evidence of depression as the only mediating factor.

“We theorize that depression might be an important mechanism through which green space may slow down cognitive decline, particularly among women, but our research is ongoing to better understand these mechanisms,” said study co-author Dr. Marcia Pescador Jimenez. 

“Based on these results, clinicians and public health authorities should consider green space exposure as a potential factor to reduce depression, and thus, boost cognition. Policymakers and urban planners should focus on adding more green space in everyday life to improve cognitive function.”

Overall, the study found that exposure to green space near homes and neighborhoods could improve processing speed and attention, and boost overall cognitive function. This aligns with previous research that has linked exposure to parks, community gardens, and other greenery with improved mental health.

“Some of the primary ways that nature may improve health is by helping people recover from psychological stress and by encouraging people to be outside socializing with friends, both of which boost mental health,” says Dr. Pescador Jimenez. “This study is among the few to provide evidence that greenspace may benefit cognitive function in older ages. Our findings suggest that greenspace should be investigated as a potential population-level approach to improve cognitive function.”

For this study, the green space metric used did not differentiate between specific types of vegetation. In a new project, Dr. Pescador Jimenez will apply deep learning algorithms to Google Street View images to better understand the elements of greenery, such as trees or grass, that could be the driving factors for health.

To further assess associations with cognitive decline, the research team hopes that their study is replicated among other ethnic populations. This is because green spaces in cities are not distributed equally, especially in urban cities. 

“Increasing everyday access to vegetation across vulnerable groups in urban cities is a crucial next step to achieve health equity,” said Dr. Pescador Jimenez.  

This study is published in the journal JAMA Network Open.

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By Katherine Bucko, Earth.com Staff Writer