Increasing Green Space Could Help In Slowing Down Cognitive Decline And Curtail Dementia Risk Factors

Boardwalk and footbridge surrounded by beech trees, Chautauqua Institution, Chautauqua, New York State, 1914. From the New York Public Library. (Photo by Smith Collection/Gado/Getty Images) 

The cliché about greenery being soothing for the soul and mind is true after all. In a recent study published in the journal JAMA Network Open, researchers analyzed how exposure to residential green space is highly beneficial for your brain. Living in a neighborhood with ample green space can slow down cognitive decline while simultaneously improving attention and mental processing speed — particularly among middle-aged women who are at a higher risk of Alzheimer Disease and other dementias.

The study’s lead author, Marcia Pescador Jimenez, an assistant professor of epidemiology at the Boston University School of Public Health and colleagues, delved into how green space and cognitive function are associated by studying 13,594 women from the nationwide Nurses’ Health Study II. This is one of the largest investigations in the United States that delved into the most common risk factors that make women vulnerable to chronic diseases.

The participants’ mean age was 61 and 98% of them were white. The team accessed the women’s data that included green space exposure and cognitive measures. Then, the researchers used a satellite-based graphical indicator — the Normalized Difference Vegetation Index (NDVI) — to remotely measure how much green space or vegetation was around the participants’ residential addresses. The data displayed each participant's address in 2013. They carried out the data analysis from June to October 2021.

They observed that the women who lived in areas with more greenery were less likely to be African American. The women were also more likely to have inherited their home from their parents and be married. Also, areas with more green space were less likely to be densely populated.

The team noted that their findings were consistent with a 2021 analysis of U.S. Medicare beneficiaries that found higher green space was associated with reduced risk of Alzheimer Disease. But they found no link between residential green space and learning and working memory. They also observed there were no differences on the impact of the green spaces in urban and rural areas.

“Higher green space exposure has been associated with lower exposure to air pollution, lower risk of depression, and increased opportunities for physical activity which, in turn, could improve cognition,” the researchers wrote in their paper.

They also observed that lower rates of depression add to how green spaces improve cognitive health. “Higher green space exposure has also been consistently linked to lower levels of depression. In addition, depression has been documented to be an important factor associated with risk for dementia,” they noted.

“The worldwide aging population and the rapid increase of dementia calls for novel prevention strategies. Our results suggest that green space exposure should be investigated as a potential population-level approach to improve cognitive function,” the researchers added.

Other than the fact that the study did not include enough non-white women, a major limitation was that there was no data on how much time each individual spent in green space and whether they were physically active or not.