Number and strength of hits drive CTE in football

Indianapolis, Indiana – According to a recent study, football players’ chances of acquiring chronic traumatic encephalopathy were connected to how frequently and severely they were hit on the head, not to how many concussions they sustained.

The largest CTE study to date, involving 631 dead football players, revealed no correlation between the risk of CTE and the number of documented concussions. The study, which was conducted at Boston University (BU), Harvard Medical School, and Mass General Brigham, was published in Nature Communications.

“These results provide added evidence that repeated non-concussive head injuries are a major driver of CTE pathology rather than symptomatic concussions, as the medical and lay literature often suggests,” said Jesse Mez, study senior author and co-director of clinical research at the BU CTE Center.

Researchers estimated the quantity and severity of head impacts suffered by football players over the course of their careers using a cutting-edge new method called a positional exposure matrix (PEM), which combined data from 34 separate research.

“This study suggests that we could reduce CTE risk through changes to how football players practice and play,” said study lead author Dan Daneshvar, MD. Assistant Professor at Harvard Medical School and Physician at Mass General Brigham affiliate Spaulding Rehabilitation. “If we cut both the number of head impacts and the force of those hits in practice and games, we could lower the odds that athletes develop CTE.”

According to the study, the presence of CTE was linked to cumulative repetitive head impact exposure. The study also discovered that models that solely relied on time on the field or the quantity of head knocks to predict CTE status and severity were less accurate.

“Although this study was limited to football players, it also provides insight into the impact characteristics most responsible for CTE pathology outside of football because your brain doesn’t care what hits it,” Daneshvar said. “The finding that estimated lifetime force was related to CTE in football players likely holds true for other contact sports, military exposure, or domestic violence.”