A recent study published in JAMA Network Open estimates that nearly 75% of former NFL players who died between 2008 and 2023 showed signs of chronic traumatic encephalopathy (CTE). And experts say it demonstrates the need to collect more data on the condition, a new study from Boston University estimating that nearly 75% of NFL players who died over a 15-year period had signs of CTE in their brains is raising concern. According to dams-O’Connor, While Boston University used “strong methods” to adjust for selection bias in the data, there are still other gaps, such as accounting for the approximately 20,000 NFL players who could have died during the study’s 15-year timeframe but did not. High airfares are weighing on Thanksgiving travel plans this year.
The research, conducted by Boston University, evaluated brain tissue from 387 deceased players, a subset of the 2,362 former athletes who passed away during that period.
Researchers adjusted for the fact that individuals with cognitive symptoms are five times more likely to donate their brains to science, leading to the estimated prevalence of 74.5% among the broader population of deceased players. Since brain donors are more likely to have symptoms believed to be related to CTE, the broad estimate reflected uncertainty about how representative brain donors studied were of the overall NFL population. Ninety-four percent of the donors had some form of CTE.
CTE is a degenerative brain condition associated with repeated head trauma. It currently remains impossible to diagnose definitively in living patients, though it has been identified in athletes, military veterans, and first responders. The new findings align with broader data released in The British Medical Journal this past August, which estimated CTE rates among former NFL players who died between 2016 and 2021 ranged from 25% to 98%. It can only be definitively diagnosed after death. Hayden Panettiere’s death ruled accidental by police in South Carolina.
Dr. Jon LaPook, chief medical correspondent, noted that the 75% figure should be viewed with caution, as the study tracked the presence of brain pathology rather than clinical symptoms. Dr. Kristen Dams-O’Connor, director of the Brain Injury Research Center at Mount Sinai, emphasized that these results do not necessarily reflect the health of current players.
She explained that many individuals in the study concluded their professional careers years ago, long before the implementation of modern safety protocols like Guardian Caps and updated concussion policies.
“This should translate to lower CTE risk in recent generations of players, compared to those who played decades ago,” Dams-O’Connor said, adding that while the Boston University methodology was robust, it cannot be generalized to the vast majority of youth or non-professional contact sport participants. The NFL stated that it remains dedicated to improving player safety through strategies designed to minimize head impacts and concussions. According to the NFL, In a statement that it “continuously strives to make the game of football safer, including by implementing strategies to reduce concussions and head impacts.
Dr. Jeremy Tanner, an assistant professor at the UT San Antonio Health Science Center, acknowledged the challenges of selection bias but noted that even conservative estimates indicate a minimum 20% to 25% prevalence, which he described as an eye-opening reality that underscores the urgent need for further research. Experts suggest that the focus must now shift toward identifying the “silent phase” of the disease to allow for earlier intervention. When you look more broadly, it’s at a minimum 20 to 25%, which is eye-opening and really shows the need to both advance the research.
Dr. Jay Alberts of the Cleveland Clinic Concussion Center argues that the disease is not truly silent, but rather requires more precise measurements to detect. He suggests monitoring “instrumental activities of daily living,” such as managing finances or driving, as potential indicators of cognitive decline similar to patterns seen in Alzheimer’s or Parkinson’s patients. Identifying such markers could potentially allow medical professionals to slow or even reverse progression. And I would argue those are things that would help us to listen more effectively,” he said, those types of activities are really insights into brain function. Where a person must use both cognitive function and motor function simultaneously, that includes skills like driving a car or balancing a checkbook.
Looking ahead, researchers are increasingly focused on identifying biomarkers that could track CTE during a person’s lifetime. Ongoing longitudinal studies, including those at UT Health San Antonio, aim to observe physiological changes in current and former players. Dr. Tanner emphasized that the rapid scientific advancements in neurodegenerative research over the last two decades—originally driven by Alzheimer’s studies—provide a foundation for future breakthroughs that could benefit a wider population facing diseases like Lewy body dementia and CTE. And has led to breakthroughs in the new therapies for Alzheimer’s disease, and hopefully (will) for many other neurodegenerative, this has really been a rapid area of scientific advancement over the last 10 to 20 years.
