The number of strokes is rising dramatically among younger and middle-aged Americans.
The American Stroke Association reported that between 1994 and 2007, strokes in young women rose 17 percent and 51 percent among men.
Researchers suggested the spike could be the result of the rise in obesity in children and young adults.
"It's definitely alarming," said Dr. Ralph Sacco, American Heart Association president and a neurologist at the University of Miami. "We have worried for a while that the increased prevalence of obesity in children and young adults may take its toll in cardiovascular disease and stroke," and that appears to be happening, he said.
Meanwhile, a preliminary study of more than 2,500 people by the Harvard Medical School showed a link between diet soda and an increased risk for stroke and heart attack.
Researchers noted there was a 48 percent increase in heart attack and stroke deaths for people who drank diet soda versus those who drank no soda.
Researchers said they don't know why there's a greater risk but speculated it could be because diet soda drinkers are living an unhealthy lifestyle.
There was no increase in people who drank regular soda.