Study finds staggering CTE numbers in ex-football players

Degenerative brain disease leads to memory loss, suicidal behaviour

Football adores statistics, but these numbers will make anyone associated with the sport cringe with worry.

The largest study to date on the brains of former football players has found some level of CTE in nearly all cases, especially in exNFL players, but also in varying degrees among former CFL players, college and high school players.

From the 202 brains studied, the degenerative brain disease known as CTE (chronic traumatic encephalopathy) was diagnosed in 177, or 87 per cent.

Former NFL players practically ran the table — 110 of 111 brains studied showed CTE, ranging in severity from mild to extreme. Data showed CTE in 48 of 53 former college players, nine of 14 semi-pros and seven of the eight ex-CFL players studied. High school numbers were fewer, at three of 14. Two other younger brains showed no CTE.

With CTE, a protein called Tau forms clumps in the brain that kill brain cells, leading to mood disorders, memory loss, dementia and suicidal behaviour. Of the 177 CTE cases, 18 ended in suicide. The median age of death was 66. The majority of suicide deaths were associated with mild CTE.

The study was published Tuesday in the Journal of the American Medical Association, based on the research of a panel of neurological scientists.

Researchers caution that there is a selection bias involved — the study only looked at brains offered for examination and many were donated by families or prearranged by the ex-player himself because he displayed symptoms of mood or behavioural issues while still living.

Despite that caveat, the data are startling even to the scientists, confirming the worst fears about repetitive blows to the brain.

Dr. Daniel Daneshvar, a neuroscientist at the Boston University CTE Research Center, was a cofirst author of the study.

“We’ve been studying CTE for eight years and it’s been in the literature since 1928,” Daneshvar said in an interview.

“We knew CTE was related to repetitive head trauma. What was surprising to us was the sheer number of athletes we found that had CTE over a relatively short time period of study.

“To find 110 players (of 111) at the NFL level was pretty surprising.”

Questions remain. Why are some players prone to CTE while others escape it? What role do drugs and alcohol play in the behaviour pattern (this study included clinical interviews with families about substance use and abuse)?

Pro players now appreciate the risks of brain trauma and can decide if it’s worth the potential financial payoff, but how worried should parents be about having their children play tackle football?

While the high school data was more encouraging — three of 14, and no severe cases — any detection of CTE in teenage brains has to be troubling.

“We don’t entrust children with life-altering decisions, and it makes you very nervous that so many of them may be subjecting themselves to the risk of this disease,” Daneshvar said.

Among the pros, CTE showed a positional pattern — it was found most among players in the so-called “trenches,” offensive and defensive linemen, then running backs and linebacker. Quarterbacks were not immune, however. In fact, Hall of Fame quarterback Ken Stabler was diagnosed with CTE.

Once among the professional deniers of a link between football and CTE, the NFL agreed in 2016 to a US$1-billion settlement to help compensate former players suffering from brain trauma.

The NHL and CFL are late to the party, and both are facing class-action lawsuits related to the brain health of ex-players. Numerous retired CFL players, including in this community, are suffering from some form of dementia. Several former Ottawa players, including Korey Banks and the late Rod Woodward, are among the names on the class-action suit against the CFL.

Daneshvar, for one, advises against continued heel-dragging on this issue.

“To a certain extent I can understand why leagues are reluctant, but the longer they choose to sit on the sidelines when it comes to making decisions to protect their players, the more likely they are to face an existential threat as we become more aware of the specific types of hits that are responsible for the development of CTE,” Daneshvar said. “If they keep waiting to do anything, people are going to be less forgiving.”

The role concussions play in the development of CTE remains unclear. Studies have not proven that symptomatic hits (eg. concussions) are more likely to result in CTE than asymptomatic hits, but Daneshvar feels that may be because concussions are difficult to document, especially after the fact. It could also be that CTE can result from hits that don’t cause concussion symptoms.

Daneshvar doesn’t shy away from the role of science in fixing the problem. Already, the search is on to find an accurate test for CTE in living brains, via scans or blood test.

“It’s gotten to the point where we as scientists need to come up with solutions to this issue,” he said.

A pill to cure, prevent or mitigate impact of CTE on the brain?

Perhaps. We know this much: Science has only begun to scratch the surface of brain disease as it relates to head blows in sport.

To find 110 players (of 111) at the NFL level was pretty surprising.