A new study published Tuesday found that at least a quarter of NFL players who died in a recent six-year period had Chronic Traumatic Encephalopathy (CTE) — and it could be as many as 97.7%.
CTE is a brain disease caused by cumulative impacts to the brain over time, such as concussions, which are common in contact sports like football, rugby and boxing. Severe CTE is associated with higher rates of dementia, as well as with mood disturbances, impaired judgement and memory loss.
The study published in The BMJ, led by researchers from Boston University’s CTE Center and other local institutions, examined the brains of 338 former NFL football players who had donated their brains to research in recent years. Out of those, 315 — 93% — had a diagnosis of CTE.
From these findings, the authors could conclude that out of the 1,712 NFL players who died between 2008 and 2021, at least 18.5% — and up to 98.7% — had CTE. For more recent deaths — players who died between 2016 and 2021 — the confirmed prevalence was even higher: at least 24.5% had CTE, and as many as 97.7%.
Dr. Daniel Daneshvar, chair of physical medicine and rehabilitation at Harvard Medical School who was the lead author of the study, pointed out these rates are striking compared to the general population.
“Less than 1% of the general population has CTE pathology,” he said. “When we found that at least 25%, and up to 98%, of individuals, had this pathology, it was deeply concerning.”
Dr. Chris Nowinski also contributed the the study. Nowinski, a neuroscientist at Boston University’s Alzheimer’s Disease Research Center, pointed out that CTE is unique in its contribution to diseases like dementia.
“There has never been an environmental exposure studied that is that bad for your brain,” he said. “Even in the old days before we took lead out of gasoline, people did not develop dementia as much as they do from playing 15 or 16 years of American football.”
Still, Nowinski — who was a college football player — believes there needs to be more awareness of the the risk that contact sports pose to the brain.
“I look back on the choices I made as a younger person and think, was my risk of CTE worth it if it’s going to take years away from my family?” He said, “We at least owe athletes, and their parents who often make this decision for them, a choice.”
