Understanding the Link Between Football and CTE
Chronic traumatic encephalopathy (CTE) and professional football have long been associated, but the exact prevalence of this degenerative brain disease has been unclear. A recent study aims to shed light on its occurrence among former NFL players.
Mass General Brigham researchers, publishing in The BMJ, investigated CTE among NFL players who died between 2016 and 2021. They found that at least 25% of them had CTE. This study analyzed players who appeared in at least one NFL game throughout their careers.
“We’ve known that repeated traumatic brain injuries can result in this disease, but we were uncertain about its commonality,” said Dr. Daniel Daneshvar, lead author of the study.
Research Methods and Results
CTE is diagnosed only through brain dissection after death. Consequently, much research relies on donated brains. Often, families and individuals suspecting CTE symptoms, such as memory issues and mood swings, decide to donate.
The UNITE Brain Bank at Boston University received over 330 NFL player brain donations from deaths between 2008 and 2021. An overwhelming 93% were diagnosed with CTE.
To establish prevalence, researchers listed all NFL players from 1949 onwards. They referenced their demographic data and CDC death certificates, identifying 1,712 deceased players. Their study focused on the 2016-2021 period, where higher brain donation rates influenced the prevalence estimate.
Daneshvar noted that 25% represents the lower bound of CTE prevalence. The actual figure may be higher due to outcomes outside the study’s sample. The study speculated a maximum prevalence of up to 97% by assuming universal presence of CTE, barring the 20 definitively cleared cases.
NFL’s Response
An NFL spokesperson affirmed ongoing efforts to enhance safety, such as strategies reducing concussions and impacts. They emphasized their commitment to providing resources for the community’s mental and physical well-being.
Examining Dementia’s Association with CTE
Exploring the CTE-dementia link formed a secondary study goal. Diagnosis challenges persist because CTE cannot be detected before death.
Researchers observed a significant correlation between dementia and Stage IV CTE, with over 90% diagnosed with dementia through medical records and input from loved ones. However, the connection weakened for earlier CTE stages or brains devoid of tau protein buildups. Intriguingly, 40% of clear samples were diagnosed with dementia.
Rachel Grashow, a Harvard neuroepidemiologist, called for further research to aid living players. She advocated discussions with doctors regarding symptoms.
Conditions like sleep apnea, high blood pressure, and low testosterone — prevalent among former players and linked to head injuries — could imitate CTE-like symptoms. Unlike CTE, these conditions are treatable.
“Conversations about CTE may discourage players from seeking treatment for treatable issues, creating a sense of hopelessness,” Grashow stated.
Implications and Future Steps
Dr. Randall Chesnut of the University of Washington praised the study’s significance, commenting on its robust sample size and analysis control. However, he noted the cohort’s average age, 66, implying pre-2005 football era occupations.
The NFL has progressively banned risky plays and invested in safer equipment research as scientific comprehension of head trauma and neurodegenerative conditions increased.
Chesnut highlighted capturing this study during a period of NFL’s late concussion recognition, hinting at potential changes by 2026.
Dementia risks extend beyond CTE. Last year, Nature Medicine revealed a 42% lifetime risk among Americans above 55 years for developing dementia.
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