Study Finds 75% of Deceased NFL Players May Have Had CTE Over 15 Years

Research Estimates High Rates of CTE in Former NFL Players

An analysis published in JAMA Network Open has found that an estimated 75% of professional football players who died between 2008 and 2023 may have had signs of chronic traumatic encephalopathy (CTE). The study represents the highest estimate to date regarding the prevalence of CTE in deceased NFL athletes.

Methodology: Combining Brain Bank Data and Death Records

The research, led by Yorghos Tripodis of the Boston University Alzheimer’s Disease and CTE Center, used data from the UNITE Brain Bank and national death records. The UNITE Brain Bank studies the effects of repetitive head trauma in donated brains, including those of athletes and military personnel. The research team evaluated information from 396 donated brains and an additional 1,966 former NFL players who died during the 15-year period. Ages of death and estimated rates of cognitive issues in players over 50 were also considered.

Addressing Potential Bias in Brain Donation

One challenge in studying CTE prevalence is the likelihood that families of individuals with cognitive decline are more inclined to donate brains or request autopsies. According to the research, families of players with symptoms were about five times more likely to donate. Tripodis and his team performed a statistical analysis to adjust for this bias, aiming for a more accurate estimate.

Key Findings: 75% May Have CTE, 27% With Dementia

The study calculated that out of approximately 2,360 former NFL players who died between 2008 and 2023, about 1,760, or nearly 75%, had signs of CTE. For comparison, only about 1% of brains donated to banks in the U.S., Austria, and Brazil have such signs. However, not every individual with evidence of CTE in the brain develops cognitive decline or dementia. Researchers estimated that about 27% of the players studied had dementia, which could be caused by various factors, though CTE may be a contributing cause in this population.

CTE and Its Symptoms

CTE results from repeated brain trauma, often from head impacts common in professional football. The condition can affect areas responsible for behavior regulation, memory, and emotions. Common symptoms include memory loss, depression, and mood swings, though some individuals may never show symptoms. CTE’s unique brain signature differentiates it from other neurodegenerative diseases, but its changes cannot be detected via scans and only appear under a microscope at autopsy.

Limitations: The Challenge of Diagnosing CTE in Living Patients

Currently, CTE can only be diagnosed after death, making all estimates, including those from this study, best approximations. Dr. Jim Kelly, a neurology expert unaffiliated with the research, noted that researchers had autopsy data from a minority of players, and some detected lesions may not have caused symptoms. “If you can’t tell if someone has a certain disease until they’re dead, you really can’t help them,” added neurosurgeon Dr. Julian Bailes, emphasizing the need for improved diagnostic tools for living patients.

Prevention and Ongoing Efforts by the NFL

Study leader Tripodis highlighted the importance of reducing brain injuries as a way to decrease CTE risk. In response, the NFL has introduced several football safety measures, attempting to minimize high-impact hits with redesigned helmets such as the Guardian Cap and the dynamic kickoff rule, both aimed at reducing collision speeds and subsequent brain injuries.

Source: nbcnews.com.