A new study in The BMJ puts a hard number on something researchers have chased for years. At least one in four former NFL players who died between 2016 and 2021 had CTE at the time of death, and that is the most conservative reading of the data, not the likeliest one. Cole and Phil walk you through where that number comes from, why it reaches well past American football, and what is actually happening inside the brain, in plain English. Learn more, get certified, take the Personal Threat and Reward Profile (PTP), and book personalized 1:1 coaching at brainwiseenterprises.com. What you get in this conversation: Daniel Daneshvar's 2026 BMJ study, and why 25% is the floor rather than the estimateThe donation bias problem, and how the same data supports a ceiling near 97%The 2022 Glasgow study on former Scottish rugby internationals and their 2.67 times higher neurodegenerative disease riskA 2025 meta-analysis placing CTE prevalence at 64.7% in rugby and 53% in American footballThe 2019 NEJM soccer study and the 3.5 times higher rate of death from neurodegenerative diseaseBobby Hull, stage 2 CTE, and what the hockey data addsTau explained as scaffolding: how impact makes it sticky, how it clumps, how it spreadsWhy subconcussive hits, not diagnosed concussions, appear to drive the cascadeYouth heading restrictions from the FA and US Soccer, and whether they go far enoughThe informed consent question the BMJ editorial puts to every contact sport If this helps you think differently about how your brain works, rate and review wherever you listen, then follow, comment, and share at @mybrainwisecoach. 00:00 The Deal No Neuroscience Jargon 02:09 The BMJ Study One In Four 03:13 Why Brain Bank Data Is Biased 04:07 What CTE Is Four Stages 05:34 Rugby Players Neurodegenerative Disease Risk 06:36 Hockey Boxing And Bobby Hull 07:16 Soccer Heading And Dementia Risk 09:34 The Technical Version Of CTE 10:53 Tau Explained As Brain Scaffolding 12:51 Subconcussive Hits The Silent Damage 14:28 Should Kids Head A Football 15:42 What Leagues Are Actually Doing 16:40 Informed Consent And Tobacco Parallel 17:55 The Scaffolding Summary Field Guide 19:11 Ten Thousand Small Hits Daneshvar, D. H., Mez, J., Nowinski, C. J., Cantu, R. C., et al. (2026). Prevalence of chronic traumatic encephalopathy among former National Football League players. The BMJ, August 25, 2026. https://concussionandcte.org/nfl-cte-prevalence-study/Russell, E. R., Mackay, D. F., Lyall, D., Stewart, K., MacLean, J. A., Robson, J., Pell, J. P., & Stewart, W. (2022). Neurodegenerative disease risk among former international rugby union players. Journal of Neurology, Neurosurgery & Psychiatry, 93(12), 1262–1268. https://doi.org/10.1136/jnnp-2022-329675Qi, et al. (2025). Prevalence of chronic traumatic encephalopathy in athletes with repetitive head impacts: a systematic review and meta-analysis. Scandinavian Journal of Medicine & Science in Sports, 35, e70047. https://doi.org/10.1111/sms.70047Mackay, D. F., Russell, E. R., Stewart, K., MacLean, J. A., Pell, J. P., & Stewart, W. (2019). Neurodegenerative disease mortality among former professional soccer players. New England Journal of Medicine, 381(19), 1801–1808. https://doi.org/10.1056/NEJMoa1908483Ling, H., Morris, H. R., Neal, J. W., Lees, A. J., Hardy, J., Holton, J. L., Revesz, T., & Williams, D. D. R. (2017). Mixed pathologies including chronic traumatic encephalopathy account for dementia in retired association football (soccer) players. Acta Neuropathologica, 133(3), 337–352. https://doi.org/10.1007/s00401-017-1680-3Boston University CTE Center (2023). CTE diagnosed in 345 of 376 former NFL players. https://www.bumc.bu.edu/camed/2023/02/06/researchers-find-cte-in-345-of-376-former-nfl-players-studied/Concussion Legacy Foundation and Boston University CTE Center (2025). Hockey Hall of Famer Bobby Hull diagnosed with CTE. https://www.bu.edu/cte/2025/02/19/hockey-hall-of-famer-bobby-hull-diagnosed-with-cte