![[Boston skyline]](http://cdn1.medicalnewstoday.com/content/images/articles/313/313071/boston-skyline.jpg)
Researchers say making changes to city design and transport could lower the burden of disease and injury worldwide.
The three-part series was led by Prof. Mark Stevenson and colleagues from the University of Melbourne in Australia.
According to the United Nations (UN) Department of Economic and Social Affairs, the world population is expected to rise by more than 2 billion by 2050, to around 9.7 billion.