Research has long connected professional football with chronic traumatic encephalopathy (CTE), a degenerative brain disease. Recent findings seek to establish its true prevalence among former NFL players. A recent study indicates that at least 25% of NFL players who died between 2016 and 2021 had CTE. This research was conducted by Mass General Brigham and published in The BMJ.
The study assessed NFL players who appeared in at least one game and died during the specified period. Results suggest a minimum of 25% had CTE, though the actual prevalence could be higher.
“We’ve known that this disease process can be caused by, in part, repeated traumatic brain injury. But we didn’t know how common it was.” — Dr. Daniel Daneshvar, study’s lead author
Chronic traumatic encephalopathy, only diagnosable after death via brain dissection, complicated existing research. Most prior studies relied on donated brains from individuals suspected of having CTE. This process made it challenging to grasp the true prevalence of the disease, not only in football players but also in veterans and other athletes.
The UNITE Brain Bank at Boston University became a pivotal resource. It houses the brains of over 330 NFL players who passed away between 2008 and 2021. 93% of these have been diagnosed with CTE. Dr. Daneshvar’s study developed a list of every NFL player who played since 1949 and cross-referenced it with death data from the Centers for Disease Control and Prevention. They evaluated 1,712 players who died during the study period, focusing on the high donation rate from 2016 to 2021.
The study notes that the actual rate of CTE could be higher due to diagnoses outside the brain bank’s samples. They discovered 215 additional cases with neurodegenerative disease causes on death certificates.
Additional study goals included exploring the link between dementia and CTE. The study showed a strong correlation with Stage IV CTE and dementia in life, but less so with lower CTE stages. Notably, around 40% of samples without CTE presented dementia, underscoring the need for more research.
Rachel Grashow, a neuroepidemiologist not involved in this study, emphasizes the importance of practical applications for this information to aid current and former NFL players. Grashow highlights conditions like sleep apnea and high blood pressure, common in ex-players due to head injuries—issues that are treatable unlike CTE.
Dr. Randall Chesnut, a neurological surgeon, noted the study’s robustness. He pointed out that most subjects’ careers ended before 2005, prior to CTE recognition, which might not represent future trends as safety measures in the NFL have improved.
A broader perspective further highlighted the risks of degenerative brain diseases. A study in Nature Medicine indicated that about 42% of Americans over 55 might develop some form of dementia regardless of brain injury history. Such statistics suggest these ailments concern the public, not only high-impact sports players.