CTE in Former NFL Players: New Study Reveals Prevalence

CTE, or chronic traumatic encephalopathy, has long been associated with professional football. However, its true prevalence has been unclear. A new study highlights that at least 25% of former NFL players, who passed away between 2016 and 2021, had CTE. This research, led by Mass General Brigham, was published in The BMJ.

Dr. Daniel Daneshvar, the study’s lead author, explains that past research relied on brain donations from individuals expecting to have CTE symptoms, like memory loss or mood swings. This led to difficulties in assessing the actual prevalence. The study analyzed the large sample collection from the UNITE Brain Bank at Boston University. Findings revealed that 93% of the over 330 donated NFL player brains had CTE. The study also utilized a broad list from the Centers for Disease Control and Prevention of players who appeared in at least one game since 1949, narrowing the list to those who died between 2016 and 2021.

The estimated prevalence of 25% is considered a minimum. The actual number might be higher because some diagnoses were made outside of the brain bank samples. Additionally, 215 players’ death certificates, who didn’t donate their brains, listed a neurodegenerative disease as the cause of death. If every player was assumed to have CTE bar the 20 cleared of a diagnosis, the upper limit could be 97%.

The NFL’s commitment to player safety includes reducing concussions and head impacts, as stated by a league spokesperson. They encourage former players to utilize resources for their physical and mental health.

CTE and Dementia Correlation

The study explored the CTE-dementia link, showing strong correlations between dementia in life and advanced Stage IV CTE diagnoses after death. Over 90% of Stage IV samples were diagnosed with dementia from medical records. Yet, the correlation was weaker for lower CTE stages. Around 40% of CTE-free samples also had dementia.

Rachel Grashow from Harvard highlights the need for research focused on living players. Symptoms related to conditions like sleep apnea and high blood pressure, common among ex-players, can mimic CTE. Unlike CTE, these conditions are treatable, urging players to seek medical attention.

Dr. Randall Chesnut from the University of Washington calls the paper “significant.” He notes it covers a large, well-controlled population. The average age at death was around 66, with careers primarily before 2005 when CTE was first diagnosed in NFL players. Recent league measures improve player safety, implying current figures may differ by 2026.

Degenerative brain diseases are not exclusive to those with brain injuries. Americans over 55 have a 42% lifetime risk of developing any form of dementia, according to a study in Nature Medicine.