Diagnosis of CTE Increases With Each Year of Ice Hockey Play

A diagnosis of chronic traumatic encephalopathy (CTE) increases with each additional year of ice hockey played, according to study results published in JAMA Network Open.

Previous research has indicated a dose-response association between amount of contact sports played and the occurrence and severity of CTE. However, little is known about the effect of repetitive head impacts (RHI) from ice hockey and CTE severity.   

Researchers conducted a cross-sectional study to determine the link between duration of ice hockey played and risk and severity of CTE.

Brain donors were enrolled in the Understanding Neurological Injury and Traumatic Encephalopathy (UNITE) and Framingham Heart Study (FHS) brain banks and whose primary RHI was from organized ice hockey play. All study participants were male athletes.

Primary sport exposure was years playing ice hockey as an RHI proxy. Ice hockey play duration was defined as total number of years of organized play.

The researchers collected retrospective data from all donors (via their informants) and their medical records were reviewed. CTE neuropathologic diagnosis was based on National Institute of Neurological Disorders and Stroke and the National Institute of Biomedical Imaging and Bioengineering (NINDS-NIBIB) criteria.

Of 77 donors (median age, 51 years; White, 100%) identified in the study, 42 were diagnosed with CTE and the remaining 35 were not. The most common causes of death in those with CTE were suicide and neurodegenerative disease (28.6% and 26.2%, respectively). The majority of former professional ice hockey players had CTE (96.4%).

The CTE rate was directly related to number of years of ice hockey play — 95.8% of donors with CTE played more than 23 years; 51.9% of donors with CTE played between 13 and 23 years; and 19.2% of donors played fewer than 13 years.

After adjusting for age at death, number of concussions, and play in other contact sports, the researchers noted a dose-response association between CTE diagnosis and increased duration of ice hockey play (odds ratio [OR] per 1-year increase in hockey play, 1.34; 95% CI, 1.15-1.55; P <.001) and increased ptau burden (0.037; 95% CI, 0.017-0.057; P <.001).

Area under the receiver operating characteristic (ROC) curve for duration of ice hockey play and CTE diagnosis was 0.89 (95% CI, 0.81-0.96). This indicated that duration of ice hockey play may be a good predictor of CTE diagnosis. Overall, those with vs without CTE were approximately 10 times more likely to have played at least 18 years of ice hockey (sensitivity, 0.70; specificity, 0.93).

Limitations of the analysis included the relatively small sample size with limited distribution of players across all levels of the sport; potential recall bias while gathering information regarding clinical data; and that duration of play was not an exact measure for RHI exposure.

“Similar to findings in American football, these findings implicate ice hockey play as a risk factor associated with CTE and associated clinical outcomes,” the researchers concluded.

Multiple study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of the authors’ disclosures.