Sam Sprinkler

How common is CTE among NFL players? A new study out today puts it at about 3 in 4. Researchers estimate that 75% of NFL players who died between 2008 and 2023 had CTE, a degenerative brain disease caused by repeated hits to the head. It’s linked to memory loss, depression, violent mood swings, impulsive behavior, and eventually dementia. It gets worse over time, and right now it can only be diagnosed after death. A 2017 study found CTE in 110 of 111 donated NFL brains (99%). A study in August said “at least 25%.” Both were off in opposite directions. The 99% only counted donated brains, and families of struggling players are far more likely to donate. The 25% counted every player who didn’t donate as CTE-free. Today’s study is the first real attempt to estimate the actual rate across all 2,362 players who died in that window, not just the 396 whose families donated. The researchers measured the donation bias directly: families of players with cognitive symptoms were about 5x more likely to donate. They adjusted for that, and the estimate still came back at 75%. Under the most conservative assumptions, it’s 64%. Even if those families were 20x more likely to donate, it would still be over 40%. For reference, CTE shows up in only 1% of brains in general-population brain banks. This means being an NFL player turns one of the rarest brain diseases into the expected outcome. The risk also scales with exposure. Earlier research from the same group found the odds of CTE roughly doubled with every 2.6 years of football played. Important caveats: CTE on autopsy doesn’t always mean symptoms, though an estimated 27% of these players also had dementia. And a 2012 study found former NFL players were 3x more likely to die of neurodegenerative disease than the general public, and nearly 4x more likely for Alzheimer’s and ALS. The study was led by Boston University and funded by the NIH and the Concussion & CTE Foundation. Co-author Chris Nowinski co-founded that foundation and advises the NFL Players Association. The NFL points to Guardian Caps as progress, but the case for them is thin. They’re only required in practice. In lab tests, one cap absorbs about 10% of impact force, and that roughly doubles only when both players wear one. Only about 20 total NFL players wore them in games last season. And Chris Nowinski, one of the study’s authors, has said they won’t protect against CTE anyway, because CTE comes from years of repeated hits, not just concussions. [links to source material in replies]