At Least 25% Of All NFL Players Who Died Between 2016-2021 Had CTE, Some Had Dementia: Medical Report Findings

A landmark study has established a stark new baseline for head injuries in professional football, revealing that at least 25 percent of all former NFL players who died over a recent five-year period suffered from Chronic Traumatic Encephalopathy (CTE).

The research, published in The British Medical Journal, provides the most definitive look yet at the true prevalence of the degenerative brain disease, successfully overcoming the “selection bias” that limited previous studies.

Prior data relied heavily on brain banks, which mostly received donations from families who noticed severe cognitive symptoms in their loved ones. This study tracked every single one of the 878 former NFL players who died between 2016 and 2021.

By cross-referencing death certificates with brain donations, researchers confirmed that 215 players had CTE. To find the absolute minimum floor of the disease’s prevalence, scientists applied a ultra-conservative model: they assumed every single unexamined brain was completely healthy.

The result proved that a minimum of 24.5% of all deceased players carried the disease.

“We’ve known that this disease process can be caused by, in part, repeated traumatic brain injury. But we didn’t know how common it was,” said Dr. Daniel Daneshvar, the study’s lead author.

“We know that 25% is the absolute floor,” added Dr. Daneshvar, who is also a researcher at Mass General Brigham in the U.K..

Among the subset of 235 families who did donate their loved one’s brain for neuropathological evaluation, the numbers were staggering. More than 91% of those examined brains tested positive for the disease.

Researchers estimate that while 25% is the statistical minimum, the maximum possible prevalence in the total population could be as high as 97.7%, with the true number sitting somewhere in between.

The study also solidified the devastating trajectory of the disease. Among the players found to have Stage IV CTE—the most severe form of the condition—more than 90% had been clinically diagnosed with dementia before they died.

In response to the findings, the NFL released a statement reinforcing its commitment to player safety. The league highlighted its ongoing investments in protective gear, such as the mandatory use of Guardian Caps during practices, and continuous updates to concussion protocols aimed at reducing head impacts.