Players competing during a game between the NHL’s Philadelphia Flyers and Florida Panthers. According to one of the new study’s authors, BU researcher Jesse Mez, “Ice hockey players with longer careers not only were more likely to have CTE, but they also had more severe disease.” Photo via AP/Matt Slocum

CTE and Ice Hockey

BU Study Finds Longer Ice Hockey Careers Increase Risk of CTE

Largest study of its kind also found 18 of 19 NHL players whose brains were studied had the neurodegenerative disease

In addition to their schoolwork and learning how to excel on the ice, Boston University hockey players are educated on a third and important area during their time as Terriers: brain health, head injuries, and concussions. “We educate them before they even get concussed,” says Arturo J. Aguilar, a medical director at BU Student Health Services and Athletics. “Symptoms can sometimes be hard to know, it could be something as small as not sleeping as well. Sometimes symptoms are delayed for hours.”

The importance of those lessons was highlighted early this month with the release of new research on ice hockey by the BU Chronic Traumatic Encephalopathy (CTE) Center. In the largest study of its kind, researchers found that the odds of having CTE, a neurodegenerative disease caused by repeated hits to the head, increased by 34 percent for each year of hockey played. The study of 77 deceased male ice hockey players, which was published in the latest issue of JAMA, the peer-reviewed medical journal of the American Medical Association, also found that 18 of 19 National Hockey League players whose brains were studied had CTE. 

While CTE is most associated with football, the study shows that its impact extends to other games where violent collisions between athletes are regular occurrences. The study focused on male hockey players because, in women’s hockey, intentional checking is forbidden, making forceful collisions far less frequent. 

“Ice hockey players with longer careers not only were more likely to have CTE, but they also had more severe disease,” says corresponding author Jesse Mez, codirector of clinical research at the CTE Center and associate professor of neurology at the BU Chobanian & Avedisian School of Medicine. “We hope this data will help inspire changes to make the game safer, as well as help former ice hockey players impacted by CTE get the care they need.”

Mez says that ice hockey players skate quickly, and that checking leads to hard impacts with other players, with the ice, with the boards surrounding the rink, and with the protective glass that rests on top of the boards. “We think years of play is a proxy for these impacts that are harder to measure directly, but are likely what are leading to the disease,” he says.

The researchers studied male brain donors who had been amateur and professional ice hockey players, in order to look for relationships between the duration of ice hockey play and CTE diagnosis and severity. They found that 27 of 28 professional players had CTE pathology (18 of 19 were NHL players and 9 others were non-NHL professional players). And they found that 46 percent of college, junior league, and semiprofessional players (13 of 28) and 10 percent of youth and high school players (2 of 21) had CTE pathology. 

Because of the high percentages the study reported, the researchers stressed “that the frequencies of CTE reported in this study should not be construed as the prevalence of CTE in the target population since families whose loved ones are symptomatic are more likely to donate their brains.” 

In men’s professional hockey, where fighting is often viewed as important to the sport’s popularity, the assumption that the most aggressive fighters, or enforcers, would be the ones most likely to suffer from repetitive head trauma is inaccurate, the researchers said. “While many perceive CTE risk as limited to enforcers, this study makes it clear that all male ice hockey players are at risk,” the CTE Center said in announcing its findings.

Among enforcers, they found 18 of 22 had CTE, but they said the difference between enforcers and nonenforcers was not statistically significant after accounting for years of play. “Enforcers have dominated the CTE conversation, but our findings provide the most evidence for the cumulative amount of play as the predominant risk factor for CTE,” Mez says. 

Aguilar says the research is important because the frequency and types of head impacts and concussions that occur in football are different than those that occur in hockey. He notes that BU has an aggressive head injury and concussion program aimed at protecting the health of its players, which includes restricting collisions during practice and making sure the players are using mouth guards, which have been shown to reduce concussions. Any player with a suspected head injury or concussion is pulled out of play, he says, and there are protocols in place that include identification of concussions, rehabilitation from concussions, and education about the symptoms.

“It’s good to see more hockey-specific research,” Aguilar says. “It could inform league rules and changes to helmets and recommendations…. As we are learning more and more, it certainly guides behavior and equipment.”

Athletes and families who are concerned their loved one is showing cognitive or behavioral symptoms that could be related to CTE pathology can reach out to BU CTE Center collaborator the Concussion Legacy Foundation’s (CLF) helpline at CLFHelpLine.org for free support. Former hockey players who would like to enroll in studies aimed at diagnosing and eventually treating CTE can sign up for the CLF Research Registry CLFResearch.org .

Funding for the study was provided by the National Institute of Neurological Disorders and Stroke; National Institute on Aging; National Heart, Lung and Blood Institute; Department of Veterans Affairs; Department of Defense; the Alzheimer’s Association; the National Operating Committee on Standards for Athletic Equipment; the Nick & Lynn Buoniconti Foundation; the Concussion Legacy Foundation; the Andlinger Foundation; and the WWE and the NFL.