Aiming to ‘make the game safer,' new BU study shines light on CTE in football

Three out of four former NFL players who died between 2008 and 2023 likely had chronic traumatic encephalopathy, or CTE, according to a Boston University study published Wednesday in JAMA Network Open.

“I understand that this could cause concern, but I believe these studies should be a call for action,” said Yorghos Tripodis, a biostatistician at the Boston University School of Public Health and one of the study’s lead researchers.

CTE, a degenerative brain disease linked to repeated blows to the head, can be diagnosed only after death.

Most research relies on donated brains, and families are more likely to donate when a player showed memory or behavior problems, which can inflate results.

Researchers used federal death records for all 2,362 former NFL players who died during the period. Of those, 396 donated their brains to BU’s brain bank, and 93.5% of those examined had CTE. Players with cognitive symptoms were about five times more likely to be donated.

Adjusting for that, researchers estimated 74.5% of all the players had some stage of CTE. Their most conservative estimate was 63.7%.

“Among those who are not exposed to repetitive head impacts, we see CTE in less than 1%,” Tripodis explained. “Now, we see among those who played (football) the longest, the prevalence of CTE is 75%.”

The authors cautioned that many cases may have been early stage with no symptoms.

The findings don’t apply to living players or to those who played only in high school or college.

“It’s not that we are anti-football,” Tripodis said. “We would like to understand what the risks are so we can make the game safer.”

The NFL acknowledged a link between football and CTE in 2016 and has since changed rules and equipment, including allowing padded Guardian Caps worn over helmets.
Tripodis said that equipment protects the skull but not the brain.

“It doesn’t do enough to protect you from these rotational movements that happen in your brain within the skull,” he added. “If we could reduce tackle football before high school, or not have tackle football during practice at all levels, as it is happening in NFL, then we will reduce the main cause of the disease.”

New England Patriots coach Mike Vrabel, a former NFL linebacker, said Wednesday he supports the league’s safety efforts, but added that players know the risks.

“You love the game so much that you know you’re going to do whatever you can to play the game,” he said.

“Studies like this are critical to improving our understanding of football’s long-term impacts,” the NFL Players Association said in a statement.

The NFLPA also said it will keep helping players and their families through programs including the Football Players Health Study at Harvard University.