New study estimates that nearly 75% of former NFL players had CTE at death

A recent study published in JAMA Network Open has revealed that nearly three-quarters of former NFL players who passed away between 2008 and 2023 likely had chronic traumatic encephalopathy (CTE) at the time of their death. This new figure significantly exceeds the previous estimate of nearly one-quarter, as reported in a study published in the British Medical Journal in August.

The JAMA study aimed to account for selection bias that often arises from brain donation, where players suspected of having CTE are more likely to donate their brains upon death. Researchers analyzed 2,362 former NFL players, of which 396 had donated their brains, and still found a notably high prevalence of CTE at 74.5%. The study's conservative lower-bound estimate still indicated a 63.7% rate of CTE occurrence.

The researchers recognized that brain bank selection was primarily driven by family members noticing cognitive symptoms. To adjust for this bias, they utilized a National Death Index-derived binary dementia cause of death variable to estimate the likelihood of CTE in non-dementia-related deaths. The study also found that 27.2% of the former NFL players studied had a history of dementia during their lifetime.

While CTE can only be diagnosed posthumously, the NFL has committed to providing resources to support the physical and mental wellbeing of its former players, encouraging them to seek treatment if they are concerned about their health.