The odds of CTE double every 2.6 years of football played

This content was originally authored by Katie Taylor in the 10/24/19 edition of our Weekly Concussion Update newsletter.

In a study published in Annals of Neurology, authors Jesse Mez et al. examined the brains of deceased athletes for evidence of chronic traumatic encephalopathy (CTE). CTE is diagnosed post-mortem by looking for abnormalities in the brain protein tau. In a healthy brain, tau protein is associated with the proper assembly of microtubule structures of neurons and is essential for cognition. In a brain with CTE, tau proteins are defective, which leads to structural tangles developing and being deposited in specific areas of the brain.

In their examination of athletes’ brains, Mez et al. found that the risk of CTE approximately doubled for every 2.6 years spent playing American football. Inherently, this study is vulnerable to selection bias, because it used brains that were donated to research, and most of the brains donated to research come from people with a history of repeated head trauma. However, after controlling for this selection bias, the magnitude of the association between time spent playing American football and CTE risk remained constant.