The Prevalence of CTE Among Former NFL Players
Study on CTE Among Former NFL Players
For years, the link between professional football and the brain disease known as CTE has been established. Yet, the true prevalence of this degenerative condition has remained uncertain. Recent findings reveal that among former NFL players who passed away from 2016 to 2021, at least 25% had CTE.
A comprehensive study conducted by researchers at Mass General Brigham, and published in The BMJ, aims to create a clearer picture of CTE prevalence in retired NFL players who have died. This study focuses on those who played at least one NFL game and died in the specified period. It found that a minimum of 25% had CTE upon their death.
“We’ve known that this disease can result from repeated traumatic brain injuries, but the commonality was unknown,” explained Dr. Daniel Daneshvar, the study’s lead author.
Challenges in Diagnosing CTE
Chronic traumatic encephalopathy, or CTE, is only diagnosable through brain dissection after death. Most research on CTE relies on brain donations from families or individuals who observed symptoms like memory loss or erratic mood swings, suspecting they might have the disease. This reliance has clouded the true picture of CTE’s prevalence, particularly in high-risk groups such as combat veterans and contact sport athletes.
Daneshvar and his team utilized samples from the UNITE Brain Bank at Boston University. More than 330 NFL players’ brains were donated between 2008 and 2021. Remarkably, 93% were confirmed to have CTE.
Estimating Prevalence
Researchers developed a list of all NFL players since 1949, referenced demographic data, and reviewed death certificates to identify 1,712 deceased players within the time frame. The study narrowed its focus to those who died between 2016 and 2021 when brain donation for research was highest.
While the lowest estimate of prevalence stands at 25%, reality suggests it could be higher. The research identified additional CTE diagnoses outside of their sample and suspected cases among players whose brains weren’t examined post-mortem. At the farthest end, CTE prevalence could be as high as 97% if assuming all but 20 players, whose brains were cleared of the diagnosis, had CTE.
“The true rate lies somewhere in the middle,” Daneshvar noted.
Implications and Recommendations
An NFL spokesperson reiterated the league’s efforts to enhance player safety and reduce concussions. Strategies include safer play rules and improving equipment.
The study also examined the link between dementia and CTE, finding a strong correlation at the advanced CTE stage. However, the connection was less clear for earlier stages or in those free of CTE indicative proteins.
This ambiguity underscores the need for further study, said Rachel Grashow, a neuroepidemiologist at Harvard. She emphasized the importance of treating related conditions that could present similar symptoms but are manageable, such as sleep apnea and high blood pressure.
“Public discussions might induce hopelessness in living players. It’s vital they consult doctors about symptoms,” Grashow stated.
Conclusion and Future Directions
Dr. Randall Chesnut praised the study as “well done and statistically sound.” It’s crucial to note that the cohort’s average age reflects players whose careers largely predate 2005—the year CTE was first diagnosed in an NFL player.
As understanding of head trauma and neurodegenerative diseases evolves, the NFL has banned certain plays and invested in safer equipment research. This study’s timeline reflects when concussion awareness was still developing, implying potential differences in future player safety and health outcomes.
Degenerative brain diseases are not exclusive to athletes. A study in Nature Medicine reported that the lifetime risk of dementia among Americans over 55 is 42%.