Twenty percent of strokes hit people under age 65, and the cause of many of those strokes remains a mystery. Having had a concussion or other traumatic brain injury might make the risk of a stroke more likely, a study says.
Back in 2011, researchers in Taiwan had unearthed an association between traumatic brain injury and stroke by combing through hospital records.
It's one of those "Oh, really?" findings that gets scientists itching to check it out themselves.