And not all of those issues are answered - just speculation about, for example, why young people are seeing an increase in strokes.
One obvious item is stroke prevention, especially for those changeable lifestyle behaviors that could really reduce risk. Check out this piece about different populations and stroke prevention:
Dr. Amytis Towfighi, senior researcher on the study, emphasized the protective role of lifestyle behaviors in stroke prevention.
"The majority of cardiovascular events including heart attacks and stroke can be prevented through changing seven modifiable risk factors, namely: smoking, obesity, physical inactivity, poor diet, cholesterol, blood pressure and blood sugar," she said.
If you've had a stroke, "it's not too late to change your lifestyle. By making immediate changes one is on the road to a longer, healthier life," said Towfighi, an assistant professor of neurology at USC's Keck School of Medicine.
Healthier lifestyle habits probably accounted for the hefty decline in strokes for seniors -- down 28 percent for those 65 to 84, and more than 22 percent for those 85 and older, Towfighi said.