Globally, one in four people over age 25 is at risk for stroke during their lifetime, according to a new scientific study. Researchers found a nearly five-fold difference in lifetime stroke risk worldwide, with the highest risk in East Asia and Central and Eastern Europe, and lowest in sub-Saharan Africa. The lifetime stroke risk for 25-year-olds in 2016 ranged from 8 percent to 39 percent, depending on where they live; people in China have the highest risk.