A new study highlights the “powerful” role that surroundings play in shaping dementia risk. 

The meta-analysis, led by researchers at the University of Georgia College of Public Health, showed that factors including air pollution and access to green and blue spaces can significantly lower the odds of cognitive decline and the development of dementia.

“These numbers show that living in a dementia-friendly environment is important to delay or prevent cognitive decline and the onset of dementia,” UGA Assistant Professor of Health Policy and Management Suhang Song, PhD, said in a statement.

The research combined 54 studies in a systematic review and 21 in the meta-analysis to quantify the effect of several factors. The findings were published in Ageing Research Reviews.

Living near major roadways was associated with a 10% higher risk of dementia, and exposure to fine particulate matter generated by vehicles and industrial emissions was associated with a 9% risk increase, according to the authors.

Alternatively, some built environments were shown to help reduce the risk of cognitive decline. Green and blue spaces — including built and natural parks, as well as bodies of water — reduced that risk by 6%. Walkability in a community, as well as access to local amenities such as food stores, community centers and healthcare, also reduced risk for cognitive decline.

“Based on these findings, we can suggest that people visit parks or forests more often, and also live further from the major roads,” Song said. “Also, living in a community where there is more walkability, or being close to local amenities like bookstores, healthcare centers and more, is helpful.”

The investigators said their findings can help inform future urban planning efforts   to create more communities that foster cognitive health.

”The biggest advantage of this paper is to quantify the association between certain factors and cognitive health,” Song said. “This analysis can provide evidence for data-driven urban planning and support decision makers.”