Study finds high rates of CTE among former NFL players
A new study estimates that approximately 75% of former National Football League players who died between 2008 and 2023 had chronic traumatic encephalopathy (CTE) — a figure that surpasses findings from previous research, reports BritPanorama.
The study, published in JAMA Network Open, aimed to provide a clearer view of the prevalence of this progressive neurodegenerative disease affecting former football players. CTE has been linked to repetitive head impacts typical in contact sports, but it has also been observed in military personnel exposed to blasts and victims of domestic violence. The condition is characterized by an abnormal buildup of the protein tau in the brain, which can begin years before symptoms manifest.
CTE can only be definitively diagnosed post-mortem and is associated with symptoms that overlap with dementia, including depression, anxiety, and memory loss. Prior studies indicated the disease was present in as many as 99% of former NFL players who donated their brains for research. However, these studies faced limitations; they often involved individuals whose families recognized symptoms prior to their deaths.
A study released in August estimated that at least 25% of former NFL players who died from 2016 to 2021 had CTE. This analysis relied on death certificates to determine the prevalence of the disease among former players compared to confirmed brain donor cases.
Researchers from Boston University’s CTE Center, including Dr. Yorghos Tripodis, focused on estimating CTE prevalence among a broader range of former NFL players, including those without noticeable symptoms or who did not donate their brains for research. They utilized data from the Understanding Neurologic Injury and Traumatic Encephalopathy brain bank and cross-referenced it with National Death Index records.
Out of 2,362 players who died during the study period, 396 had donated their brains for research. Among this group, 93.5% (or 362 players) were diagnosed with CTE, and nearly 70% of those studied were aged 70 or older at the time of death.
The analysis revealed that former players presenting cognitive symptoms of dementia were five times more likely to have donated their brains. The researchers adjusted their calculations to account for the likelihood of brain donation, aiming to apply these findings to the general population of former players.
The NFL responded to the study by reiterating their commitment to player safety, emphasizing ongoing efforts to reduce concussions and providing resources for former players’ health and wellbeing. The league stated, “The NFL remains committed to ensuring that the NFL community has access to a robust – and expanding – set of resources to enhance their physical and mental well being.”
While Dr. Tripodis acknowledged limitations in the study—particularly the presence of selection bias—he pointed out that evidence of CTE does not imply all players will exhibit symptoms. “Our numbers suggest that the prevalence of dementia, which is the most severe type of cognitive symptoms, is four times higher than the general population among the NFL players,” he stated.
Experts like Dr. Rachel Grashow cautioned about understanding brain donation motivations, suggesting that if various influencing factors are not accounted for, the data could be skewed. She emphasized the need to distinguish between CTE and the symptoms of dementia, noting that CTE does not always correlate with cognitive decline.
Dr. Julie Stamm expressed surprise at the high number of CTE cases found post-adjustment for brain donation likelihood, suggesting that the NFL has room for improvement in promoting youth safety measures that could reduce concussion risks. “If the NFL says that, the youth levels, the younger levels, they’ll listen, and that will go a long way in decreasing the overall number of impacts over a lifetime,” Stamm said.
As researchers continue to refine criteria for diagnosing CTE in living patients, Dr. Tripodis highlighted the importance of these findings for future research funding and developing clinical trials aimed at addressing the disease.
