# Study Estimates 75 Percent of Former NFL Players Develop CTE Analysis of medical records reveals high prevalence of brain disease among deceased professional football players. - **Source:** [Scientific American Content: Global](https://brifing.si/source/4f066134-e06d-4415-87ef-305e3dc2aba6) - **Published:** 2026-10-28 - **Original article:** - **On Brifing:** https://brifing.si/s/a92bf2f6-5b66-46a4-b259-f9f38255c7ff ## High CTE Prevalence Identified A landmark study published in JAMA Network Open estimates that approximately 75 percent of former NFL players likely died with chronic traumatic encephalopathy. This analysis utilized medical records from 2,362 deceased athletes who played in the league for an average of five years between 2008 and 2023, highlighting significant long-term health risks. ## Brain Donation Selection Bias Researchers observed that 93.5 percent of the nearly 400 brain donors in the study showed signs of CTE. However, this figure is likely skewed because individuals with severe behavioral symptoms are five times more likely to donate their brains to science, necessitating statistical adjustments to estimate the broader population risk accurately. ## Comparison to General Population The incidence of CTE among former NFL players stands in stark contrast to the general public. Data from community-based brain banks indicate that fewer than 1 percent of brains in the non-athlete population show signs of the disease, underscoring the unique occupational hazards associated with repetitive head impacts in professional football. ## Pathology and Clinical Symptoms Signs of CTE identified in the study include brain atrophy and clusters of tau protein, which are also associated with Alzheimer’s disease. These physical changes are linked to clinical symptoms such as dementia and mood swings, though diagnosing the disease in living players remains a significant challenge for the medical community today. ## Methodological Limitations Acknowledged Experts note that the 75 percent estimate is derived from a statistical model and includes early-stage pathology that may not have caused symptoms. Furthermore, death records can be imprecise, as dementia is often underreported or attributed to multiple causes, making it difficult to isolate football as the sole contributing factor. ## Need for Further Research Russell Lonser of Ohio State University emphasizes that without a control group of individuals who never played contact sports, determining the exact causal link remains difficult. Future research requires longitudinal studies of both symptomatic and asymptomatic players, alongside brain analyses, to fully understand the progression and specific triggers of the disease. ## Mitigation and Prevention Strategies While the NFL has implemented various measures to reduce head injuries, the long-term efficacy of these changes is still being evaluated. Researchers maintain that CTE is a preventable condition, noting that reducing the frequency and intensity of head impacts over a lifetime is the most effective way to lower individual risk. ## Impact on Future Players The findings serve as a critical resource for families affected by CTE and provide essential data for current athletes to assess their own risks. By quantifying the prevalence of the disease, the study aims to inform better safety protocols and awareness, ultimately shaping the future of health standards within professional contact sports. ## Sources covering this story - https://www.scientificamerican.com/article/landmark-study-finds-three-in-four-nfl-players-die-with-cte/ — --- _Summary written by Brifing from the original reporting. Copyright in the original article belongs to its publisher; read the full piece at the link above._