Study: Women surrounded by greenery less likely to suffer depression or dementia

By Stephen Beech via SWNS

Middle aged women who like to be surrounded by plants and flowers are less likely to suffer depression or dementia, according to a new study.

Researchers found that living in areas with more greenery also improves brain processing speed and attention, as well as overall cognitive function - which is a strong predictor of whether a person may develop dementia later in life.

They say that increasing green space in residential areas could help improve cognition function in middle-aged women and that the association might be explained by a reduction in depression, which is also a risk factor for dementia.

The findings, published in the journal JAMA Network Open, show that exposure to green space around one’s home and surrounding neighborhood could improve brain processing speed and attention, as well as boost overall cognitive function.

The results also showed that lowered depression may help explain the association between green space and cognition, bolstering previous research that has linked exposure to parks, community gardens, and other greenery with improved mental health.

Study lead author, Dr. Marcia Pescador Jimenez, said: “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.

“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 the study, the American research team estimated residential greenspace using satellite images.

They measured psychomotor speed, attention, learning, and working memory among more than 13,500 mainly white women with an average of 61.

Adjusting for age, race, and individual and neighbourhood socio-economic status, the researchers found that greenspace exposure was associated with psychomotor speed and attention, but not learning or working memory.

In addition to depression, the researchers also examined the potential roles of air pollution and physical activity in explaining the association between greenspace and cognitive function, and they were surprised to only find evidence of depression as a mediating factor.

Dr. Pescador Jimenez, Assistant Professor of epidemiology at Boston University School of Public Health (BUSPH), said: “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.

“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.”

She said that while the study shows evidence of the association, the green space metric that the team used to measure green space exposure does 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 which specific elements of greenery - such as trees or grass - could be the driving factors for health.

She added: “The distribution of green spaces in cities is not uniform.

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