A study published Wednesday in JAMA Network Open suggests that approximately 75% of deceased NFL players who died between 2008 and 2023 likely had chronic traumatic encephalopathy (CTE).
The research, which analyzed the donated brains of 396 former professional football players and death records from 1,966 NFL players within that 15-year span, found that about 93.5% of the donated brains exhibited signs of CTE.
CTE is a degenerative brain disease associated with repetitive head impacts, often seen in individuals who participate in contact sports. Symptoms can include mood swings, depression, and memory loss, and the disease can only be definitively diagnosed after death.
Christopher Nowinski, CEO of the Concussion & CTE Foundation, stated that CTE is a preventable disease and that limiting repetitive head impacts in football could reduce its prevalence in future generations.
This study's findings contrast with a different study published in August, which estimated that only 25% of deceased players between 2016 and 2021 had CTE.
The NFL responded by referring to a previous statement from the August study, asserting the league's commitment to player safety and providing resources for player well-being. "The NFL continuously strives to make the game of football safer, including by implementing strategies to reduce concussions and head impacts," the statement read. "The NFL remains committed to ensuring that the NFL community has access to a robust — and expanding — set of resources to enhance their physical and mental wellbeing."
The NFL Players Association acknowledged the importance of such research. "The NFLPA remains committed to supporting scientific research, investing in resources that aid players’ physical and mental well-being, and expanding access to care so that they can experience improved health outcomes during and after their playing careers," the union said in a statement.