LONDON (AP) — A new study says strokes are increasingly hitting younger people, and the incidence of the crippling condition worldwide could double by 2030.

Scientists have looked at more than 100 studies from 1990 to 2010, and have found that strokes worldwide have jumped by a quarter in people ages 20 to 64. And those patients make up almost one-third of the total number of strokes.

Researchers in London say most strokes still occur in the elderly and many can't be avoided, but there's a growing number of young people with risk factors for stroke, such as obesity, diabetes and high blood pressure.

Majid Ezzati of Imperial College London, who worked on the study, says countries should focus on reducing smoking rates, aggressively controlling blood pressure and improving eating habits.