Association between contact sports participation and chronic traumatic encephalopathy: a retrospective study.
Bieniek KF, Blessing MM, Heckman MG, Diehl NN, Serie AM, Paolini MA, Boeve BF, Savica R, Reichard RR, and Dickson DW. Brain Pathol. 2019. [Epub Ahead of Print].
Take Home Message: Among 750 samples of brain tissue from individuals with and without a history of sport participation, less than 6% of people showed chronic traumatic encephalopathy(CTE)-related pathology. While most people don’t develop CTE, roughly 1 in 7 former football players had evidence of CTE-related pathology compared with ~1 in 18 peers.
Chronic traumatic encephalopathy (CTE) is a debilitating neurological disorder that has gained a lot of attention because it is related to repeated brain trauma. Despite the media attention, we know very little about whether the risk of developing CTE is related to participation in sports at nonelite levels of competition. The researchers of this study used the Mayo Clinic Tissue Registry to review samples of brain tissue from 300 former athletes and 450 non-athletes for the presence of CTE pathology or features of CTE. The researchers used obituaries and high school yearbooks to determine if someone participated in sports (e.g., football, hockey, soccer). They also used The Rochester Epidemiology Project, which is a comprehensive medical records linking system, to identify relevant disorders (e.g., head trauma, dementia, alcoholism). The researchers identified CTE based on consensus criteria and features of CTE when a person had multiple lesions that were possibly CTE, but they failed to fit all of the consensus criteria (excluding Alzheimer-type pathology and aging-related tau pathology). Overall, 66 out of 273 females (24%) and 232 out of 477 males (49%) participated in a contact sport. Forty-two (5.6%) people had evidence of CTE-related pathology (CTE or features of CTE). Only one female had any CTE-related pathology. A male with a history of participation in American football was ~2.6 times more likely to have CTE-related pathology than a peer (CTE-related pathology: 15% vs 6%; confirmed CTE: 8% vs 3%).
This study is yet another piece in the puzzle of understanding how participation in sports may impact the development of CTE. While more research in this area is needed, the results support prior findings (see below) that participation in football increases the chances of CTE development. In fact, more than 1 in 7 former football players in the cohort had evidence of CTE-related pathology compared with ~1 in 18 peers. A more detailed analysis with a larger cohort may help us understand who will get this pathology among people with and without a history of football. This information will be vital to developing prevention strategies. Some caution should be taken from this study as the researchers were unable to assess the years of participation and/or number of head traumas that a person experienced. Despite this limitation, clinicians can use this study to help educate athletes and parents regarding CTE and sports participation. Clinicians should highlight that while football players are more likely to develop CTE, the vast majority of participants (85%) may not develop CTE and we are trying to figure out why some people develop CTE. Parents and athletes can then make an informed decision about the risks and benefits of participating in football.
Questions for Discussion: What questions have you had from your athletes or parents regarding CTE? How might this study impact your education of these populations moving forward?
Written by: Kyle Harris
Reviewed by: Jeffrey Driban