Boston, Mass. – The largest study ever of 77 deceased male ice hockey players by the Boston University CTE Center found that the odds of having chronic traumatic encephalopathy (CTE) increased by 34% each year played, and 18 of 19 National Hockey League players had CTE. CTE is a neurodegenerative disease caused by repeated traumatic brain injuries and most frequently found in former contact sport athletes exposed to repetitive head impacts (RHI). While many perceive CTE risk as limited to enforcers, this study makes it clear that all male ice hockey players are at risk.
“Ice hockey players with longer careers not only were more likely to have CTE, but they also had more severe disease,” explains corresponding author Jesse Mez, MD, MS, co-director of clinical research at the CTE Center and associate professor of neurology at Boston University 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.”
To investigate the relationships between duration of ice hockey play and CTE diagnosis and severity, the researchers studied male brain donors who had been amateur and professional ice hockey players. They found 96% (27 of 28) of professional players had CTE pathology (18 of 19 NHL, 9 of 9 non-NHL professionals), 46% of college, juniors and semi-professional players (13 of 28) and 10% (2 of 21) youth and high school players. The researchers stress 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.
Among enforcers, they found 18 of 22 had CTE, but the difference between enforcers and non-enforcers 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,” says Mez. “Enforcers had about twice the odds of developing CTE, but the takeaway here is that non-enforcers are getting CTE as well. Ice hockey players skate quickly, and checking leads to impacts with other players, the ice, boards and glass. 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.”
Ice-hockey is the third major sport, after American football and rugby, to show a dose-response relationship between years of play and CTE risk, further strengthening the evidence that repetitive head impacts cause CTE. The risk for CTE among female ice hockey players remains unknown, and because the rules around checking differ, the results should not be generalized to female ice hockey players.
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 (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 .
These findings appear online in JAMA Network Open.
Funding for the study was provided by the National Institute of Neurological Disorders and Stroke (U54NS115266, U01NS086659, U01NS093334, R01NS078337, R56NS078337, K23NS102399), National Institute on Aging (P30AG13846; supplement 0572063345, U19AG068753, R01AG061028, K23AG046377, R21HD089088, F32NS096803), National Heart, Lung and Blood Institute (75N92019D00031), Department of Veterans Affairs (I01 CX001135, CSP 501, B6796-C), Department of Defense (W81XWH-13-2-0095, W81XWH-13-2-0064, W81XWH1810580, PRARP-13267017), the Alzheimer’s Association (NIRG-15-362697, NIRG-305779), the National Operating Committee on Standards for Athletic Equipment (NOCSAE), the Nick and Lynn Buoniconti Foundation, the Concussion Legacy Foundation, the Andlinger Foundation, the WWE, and the NFL.
About the BU CTE Center
The BU CTE Center is an independent academic research center at the Boston University Avedisian & Chobanian School of Medicine. It conducts pathological, clinical and molecular research on CTE and other long-term consequences of repetitive brain trauma in athletes and military personnel. For people considering brain donation, click here. To support its research, click here.
Contact
Gina DiGravio
Boston University School of Medicine
[email protected]
Office: 617-358-7838
Cell: 617-224-8962