BOSTON (WHDH) -- Boston University School of Medicine released an extensive study of the brains of dead athletes and others that show most had signs of brain damage after suffering repeated head injuries.

The study published Monday reports on the autopsies of 85 brain donors.

The autopsies revealed extensive evidence of protein tangles clogging brain tissue and causing the destruction of brain cells in football players, wrestlers, hockey players, boxers, and military combat veterans.

The researchers reported that 68 of the 85 individuals they examined, all of whom had experienced repeated head trauma, had evidence of chronic traumatic encephalopathy.

“These 68 people had this disease called CTE, which is a degenerative disease that is associated with a history of repetitive brain trauma,” said Dr. Robert Stern of the Center for Study of Traumatic Encephalopathy.

The study comes months after former New England Patriots linebacker Junior Seau took his own life and left his brain to science.

The release of the study also comes on the heels of this weekend’s tragedy involving Kansas City Chief’s linebacker Jovan Belcher, who allegedly shot and killed his girlfriend and then took his own life. A co-author of the BU study said it is impossible to know if football damaged Belcher’s brain.

“Could football-related brain trauma be related to it, associated with it at all? It’s possible, but we’ll never know,” said Stern.

Former professional wrestler Chris Nowinski quit the sport years ago after a series of concussions.

“Ten years ago my head was throbbing every day. I couldn’t sleep. I couldn’t think straight,” said Nowinski.

As a co-author of the study, Nowinski and his colleagues believe the issue of concussions in sports needs to be taken seriously.

“On the prevention side I think it’s a real wakeup call that there are real consequences to getting hit in the head and especially it means we need to make more changes at the youth level,” said Nowinski.

Doctors involved in the study said the Massachusetts Concussion Law was a step in the right direction, but more needs to be done to limit hits to the head.

The Associated Press contributed to this report.