Cognitive function in middle age is a strong predictor of whether a person may develop dementia later in life. According to a recent study published online by JAMA Network, Increasing residential green space may be associated with modest benefits in cognition in middle-aged women.
According to the study lead, Marcia Pescador Jimenez, an assistant professor of epidemiology at Boston University School of Public 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,”
The study involved about 14,000 women, predominantly white (98%) with an average age of 61. The researchers found that increasing green space was associated with higher scores on overall cognition and psychomotor speed/attention. However, the researchers found no association between green space and learning/working memory.
Previous studies have linked exposure to green space with lower exposure to air pollution and lower risk of depression. Exposure to green space may improve cognitive function through increasing opportunities for physical activity, social engagement, psychological restoration, improving cognitive capacity, and reducing the negative consequences of noise and air pollution.
The researchers also examined the potential roles of air pollution and physical activity in explaining the association between green space and cognitive function. They found out that green space may be associated with cognitive function through depression. However, they did not find any association between green space and cognitive function mediated by air pollution or physical activity.
“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,” Pescador Jimenez says.
There are some limitations to this study. For example, the study involved a predominantly white study population, which could affect its generalizability. The researchers hope their study is replicated among other racial/ethnic populations.
In addition, despite the study showing an association between green space and cognition, the greenspace metric that the researchers used to measure exposure does not differentiate between specific types of vegetation.
“The distribution of green spaces in cities is not uniform,” says Pescador Jimenez. “Increasing everyday access to vegetation across vulnerable groups in urban cities is a crucial next step to achieve health equity.”
SOURCE: JAMA NETWORK and Boston University School of Public Health.
