New CTE Study Finds at Least 25 Percent of Deceased NFL Players Affected

The first large-scale study of its kind since the NFL began changing rules and talking about player safety in earnest has delivered a sobering baseline: at least one in four former players who died between 2016 and 2021 had chronic traumatic encephalopathy.

The Numbers Behind the Headlines

Researchers examined 152 brains of former NFL players donated to a brain bank during that six-year window. They diagnosed CTE in 41 of them—27 percent. The figure, published Tuesday in the Journal of the American Medical Association Neurology, is lower than some earlier, smaller studies that focused on players who had already shown symptoms or whose families suspected CTE. Yet it is the first to look at a broader, more recent cross-section of deaths.

Even with all the rule changes, the data keep showing that the hits add up.

NPR

What the League Says—and What the Data Show

The NFL has invested millions in player safety research, neck-strengthening programs, and stricter tackling rules. It has also fought in court to limit liability for former players. In response to the new paper, a league spokesperson told ESPN the findings “underscore the importance of our continued work” on concussion protocols and that “the vast majority of players do not develop CTE.”

That last claim is technically true within the study’s sample—73 percent of the brains showed no CTE. But the 27 percent figure still represents a disease rate orders of magnitude higher than in the general population. Earlier Boston University research on a different, symptom-selected sample had put prevalence above 90 percent; this broader look tempers those numbers without erasing the central problem.

The Human Cost on the Field and After

CTE is not a tidy diagnosis. Symptoms can include depression, explosive anger, memory loss, and dementia—conditions that destroy marriages, careers, and lives long after the final whistle. Families of players diagnosed in this study described the familiar arc: a charismatic athlete slowly becoming unrecognizable, then dying too young.

The disagreement in the room is no longer whether football causes brain damage in a meaningful percentage of players. It is how high that percentage must climb—and how many current players must be affected—before the sport’s structure changes in ways that actually reduce, rather than manage, the risk. The new data give advocates and neurologists fresh ammunition; the league, as it has for years, treats each study as a call for more incremental reform.

At some point the incrementalism itself becomes the story. Tuesday’s paper is not revolutionary, but it is cumulative. Another 25 percent added to the ledger, another cohort of widows and children left to wonder what the game ultimately cost.