GOLDEN VALLEY, Minn. — Anyone who plays or watches hockey knows it's a contact sport.
But a first-of-its-kind study is now proving just how easy it is to develop chronic traumatic encephalopathy or CTE.
The brain disease is often associated with football, but the new research out of Boston University and it's leading CET Center found a hockey player's odds increase a whopping 34% every year they play.
"None of this stuff really surprises me," said former NHL player Jordan Leopold. "I’ve lived it, I’ve had my own share of concussion problems."
The once defenseman is a Minnesota native who played professionally for 13 years and remembers his fair share of concussions.
"Good ones? Couple handful, I'd say and I'd probably double that with the ones I didn't know about, but it's prevalent in contact sports," said Leopold.
Doctors have long since proven that CTE is caused by repeated exposure to repetitive head impacts. An abnormal protein accumulates in the brain and it's best confirmed post-mortem. But before that, it can include symptoms like memory problems and aggression, often leading to dementia, according to Dr. Jesse Mez.
"Nothing like this exists anywhere else, so this is a really unique resource," said Dr. Mez, who's a neurologist at Boston University and helped lead the new study.
The school's CTE Center currently has about 1,500 donated brains available for research, many of whom are former hockey players.
The study is also the largest ever of 77 deceased male hockey players between the ages of 33 to 73. Dr. Mez says the data makes it clear that all male hockey players are at risk and its not limited to enforcers. And that players with longer careers not only were more likely to have CTE, but they also had more severe diseases.
"I think each time I see it, I'm a little bit surprised how well we can model that relationship and that it really exists as clearly as it does," said Dr. Mez.
"We're much more aware of concussions and what the lifetime impact will be than we were 20-plus years ago," said Leopold, who retired in 2015.
He now coaches a local high school hockey team and already sees changes to make the sport more safe from softshell helmets to limiting checking until a later age. He also knows contact can't be stopped completely.
"It drives the entertainment factor, so there's a fine line, how do you go to protect people and how do you still keep the sport pure without taking what the people want to see away from it," said Leopold.
Dr. Mez says it's possible to make changes and still reap the benefits of team sports, all while protecting a player's well-being.
"I’m not in the business of telling people what to do," said Dr. Mez. "I’m in the business of giving them information so that they can make the choices they think are best."
The study included players with a variety of playing time from just a couple years to 30 years. But Dr. Mez said more of them were considered elite players who would have already been having CTE symptoms.