(CN) – Greener cities translate to citizens with better mental health, according to a study published Monday in the American Journal PNAS.

Children who grow up near plentiful green spaces have up to 55 percent less risk of developing various mental disorders later in life, the study’s authors from Aarhus University in Denmark say.

The World Health Organization estimates more than 450 million people suffer from a mental disorder, a figure that’s expected to continue climbing. At the same time, an ever larger share of the world’s population now lives in cities where mounting research has already shown that noise, air pollution, infections and poor socioeconomic conditions increase the risk of developing a mental disorder.

Monday’s study supports what others have shown, that more green space in the local area creates greater social cohesion and increases the level of physical activity. This in turn can improve children’s cognitive development and ultimately may have an impact on people’s mental health.

Postdoctoral candidate and lead author Kristine Engemann, from Aarhus’s Department of Bioscience and the National Centre for Register-based Research, explained in a statement the importance and uniqueness of their data.

“Our data is unique. We have had the opportunity to use a massive amount of data from Danish registers of, among other things, residential location and disease diagnoses and compare it with satellite images revealing the extent of green space surrounding each individual when growing up,” Engemann said.

Engemann and professors Carsten Bocker Pedersen and Jens-Christian Svenning mapped the presence of green space around the childhood homes of nearly 1 million Danes using satellite data from 1985 to 2013. They then looked at data on the risks of developing one of 16 different mental disorders later in life.

Even after adjusting for other known risk factors such as socioeconomic status, urbanization, and a family history of mental disorders, the children surrounded by a lot of green space fared better mentally as they grew into adulthood.

“With our dataset, we show that the risk of developing a mental disorder decreases incrementally the longer you have been surrounded by green space from birth and up to the age of 10. Green space throughout childhood is therefore extremely important,” Engemann explained.

“There is increasing evidence that the natural environment plays a larger role for mental health than previously thought. Our study is important in giving us a better understanding of its importance across the broader population.”

Engemann and her colleagues believe their data confirming the positive impact of green spaces can better inform sustainable urban planning as cities continue to evolve and grow.

“The coupling between mental health and access to green space in your local area is something that should be considered even more in urban planning to ensure greener and healthier cities and improve mental health of urban residents in the future,” Svenning said.