A Boston University study published Wednesday in JAMA Network Open estimates that nearly three-quarters of NFL players who died between 2008 and 2023 had chronic traumatic encephalopathy, or CTE, a degenerative brain disease caused by repeated hits to the head.
The researchers used statistical methods to analyze data from more than 2,300 players, including those who donated their brains as well as death records for players who died over the 16-year period. They looked for causes of death by neurodegenerative diseases like dementia. The work builds on research released in August that estimated between 25% and 98% of players had CTE based on a study of donated brains.
Dr. Ann McKee, a neurologist and neuropathologist who directs the Boston University CTE Center and worked on the study, said the importance of the number is knowing that football played at the professional level is a real risk for this disease, and it's time for all of us to work together on ways of prevention, ways to keep our players safe.
Former Patriots linebacker Ted Johnson said he wasn't surprised by the estimate. He said he is alarmed by the figure and called it clearly an epidemic. Johnson said he suspects he has CTE himself after a decade in the NFL, and estimated he experienced more than 100 concussions over his football career. He said he suffers from symptoms including depression, anxiety, difficulty with impulse control, sleep issues and irritability.
McKee said she hopes the study serves as a wake-up call. She described CTE as a preventable disease and recommended steps such as raising the age children start playing football, reducing full contact in practice, reducing the number of games in a season, and monitoring athletes' head hits. She said she is optimistic that doctors will gain the ability to diagnose people with CTE while they are living within the next few years.
Johnson said the ability to diagnose CTE in living athletes would be a game changer. He questioned what the landscape of football would look like if young players could get tested.
When asked for comment, an NFL spokesperson referred to a previous statement saying the league continuously strives to make the game of football safer, including by implementing strategies to reduce concussions and head impacts. The spokesperson added that the NFL community has access to resources for physical and mental wellbeing, and the league has implemented rule changes, a new concussion protocol, and safer helmets.
Analysis
Why This Matters
- The study provides the most rigorous estimate yet of CTE prevalence among NFL players, highlighting a significant health crisis in professional football.
- It underscores the urgent need for prevention, including potential changes to youth sports, practice structures, and game rules.
- The push for a diagnostic test for living patients could dramatically alter the legal, medical, and personal landscape for current and former athletes.
Background
CTE is a neurodegenerative disease linked to repeated hits to the head. Currently, it can only be formally diagnosed after death. The Boston University study improves on previous estimates by using statistical models to account for potential bias in brain donation samples.
Key Perspectives
Dr. Ann McKee (neurologist, BU CTE Center): Says the findings are a wake-up call, describing CTE as a preventable disease and advocating for structural changes in football, such as raising the starting age and reducing head hits in practice.
Ted Johnson (former Patriots linebacker): Expresses alarm at the estimate, calling it an epidemic. He suspects he has CTE and worries about the long-term viability of the sport if living diagnosis becomes possible.
NFL spokesperson: States the league continuously works to make the game safer through rule changes, concussion protocols, and helmet innovation, and that resources are available for player wellbeing.
What to Watch
- Progress on developing a diagnostic test for CTE in living people, which McKee expects within the next few years.
- Whether the NFL and other contact sports leagues adopt the specific preventive measures McKee recommended.
- Potential impact on youth football participation and public policy regarding liability and player safety.
Checked
12 claims in this story checked against 1 source: 8 supported.
Show each claim
- Partly supportedThe headline says nearly three-quarters of NFL players in the study had brain disease, without limiting the claim to players who died during the study period or preserving that it is an estimate.WBUR News: “A new study from a team of researchers in Boston estimates that nearly three-quarters of NFL players who died between 2008 and 2023 had chronic traumatic encephalopathy, or CTE.”
- Partly supportedThe summary says the BU study warns of widespread CTE risk in professional football.WBUR News: “The importance of this number is knowing that football played at the professional level is a real risk for this disease”
- SupportedThe study estimates that nearly three-quarters of NFL players who died between 2008 and 2023 had CTE, and its results were published Wednesday in JAMA Network Open.WBUR News: “A new study from a team of researchers in Boston estimates that nearly three-quarters of NFL players who died between 2008 and 2023 had chronic traumatic encephalopathy, or CTE. ... The results were published Wednesday in JAMA Network Open.”
- SupportedCTE is a degenerative brain disease caused by repeated hits to the head.WBUR News: “The disease is caused by repeated hits to the head, whether they cause a concussion or not.”
- SupportedResearchers analyzed data from more than 2,300 players, including some who donated their brains and death records for players who died during the 16-year period.WBUR News: “The researchers used statistical methods to analyze data from more than 2,300 players, including some who donated their brains, as well as death records for players who died over the 16-year period.”
- SupportedResearch released in August estimated that between 25% and 98% of players had CTE, based on a study of donated brains.WBUR News: “The work builds on research released in August that estimated between 25% and 98% of players had CTE based on a study of brains donated by players and their families.”
- SupportedMcKee said professional football is a real risk for CTE and that people should work together on prevention and player safety.WBUR News: ““The importance of this number is knowing that football played at the professional level is a real risk for this disease, and it's time for all of us to work together on ways of prevention, ways to keep our players safe,” said Dr. Ann McKee”
- SupportedTed Johnson said he was alarmed by the estimate and called it an epidemic.WBUR News: ““I am certainly alarmed by that figure. That's clearly an epidemic,” he said.”
- Partly supportedJohnson estimated that he experienced more than 100 concussions over his football career.WBUR News: “He suspects he has CTE himself after a decade playing in the NFL, and estimated he experienced 100-plus concussions over his football career.”
- SupportedJohnson suspects he has CTE after a decade playing in the NFL.WBUR News: “He suspects he has CTE himself after a decade playing in the NFL”
- SupportedMcKee is optimistic doctors will be able to diagnose CTE in living people within the next few years.WBUR News: “McKee said although this finding is grim, she’s optimistic that in the next few years, doctors will gain the ability to diagnose people with CTE while they’re living.”
- Partly supportedThe NFL has implemented safer helmets.WBUR News: “The NFL has also implemented rule changes and a new concussion protocol and is pushing for the development of safer helmets.”
