Study: 87 of 91 deceased NFL players tested positive for CTE

New figures show that 87 of 91 deceased former NFL players have tested positive for the brain disease CTE.

New figures show that 87 of 91 deceased former NFL players have tested positive for chronic traumatic encephalopathy (CTE).

Figures from the Department of Veterans Affairs and Boston University have identified the degenerative brain disease in 96% of NFL players and 79% of all football players they have examined. The brain bank is the nation's largest focused on the study of head injury and trauma, and shared its numbers with PBS's Frontline.

CTE is believed to be caused by repetitive head trauma, with effects including memory loss, depression and dementia. The lab has found CTE – which can only be definitively identified after death – in 131 of 165 subjects who played football professionally, semi-professionally, in college. Offensive and defensive lineman make up 40% of the positive test subjects. Past research has suggested that frequent, lesser on-field head injuries could pose the biggest risk, rather than isolated, more violent incidents that directly cause concussions.

The new numbers are “remarkably” in line with the center's past research surrounding football and brain disease.

“People think that we’re blowing this out of proportion, that this is a very rare disease and that we’re sensationalizing it,” said Dr. Ann McKee, the director of the facility and chief of neuropathology at the VA Boston Healthcare System. “My response is that where I sit, this is a very real disease. We have had no problem identifying it in hundreds of players.”

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- Jeremy Woo