Estimating brain health in retired athletes isn’t easy

In the series “Let Me Explain,” UNC College of Arts and Sciences’ faculty shed light on an intriguing, timely or often misunderstood topic related to their research. This installment features recent findings about retired football players’ brain health by exercise and sport science faculty: research associate professor Wesley Cole, professor and director of the Matthew Gfeller Center Jason Mihalik, and teaching associate professor J.D. DeFreese.

Why is it important to study how high-contact sports affect the brain, especially for career professionals?

Football players are at risk for many hits to the head throughout their playing careers. Even if a single impact isn’t enough to cause a concussion, there is concern that the cumulative effect of numerous “subconcussive” blows could be linked to long-term negative cognitive and mental health outcomes.

Often, career length and playing position have been used as estimates of how much head impact exposure a player accumulated. However, in our experience studying hundreds of former NFL players, the factors that drive long-term outcomes are more nuanced. We felt it was important to leverage the data we have collected over many years from retired NFL players who have consented to participate in our studies to determine if length of playing career and certain playing positions are associated with negative long-term cognitive and mental health outcomes.

You and your colleagues found that long-term cognitive performance and mental health don’t significantly correlate with length of players’ careers or their playing position. How might this discovery impact how we assess brain health in athletes?

After a player’s career, it can be difficult to estimate how many concussions they experienced. Our findings suggest career length and playing position don’t hold up well as proxies. This is important because if the proxy isn’t a good estimate for head injury exposure, it can distort both clinical decisions and research conclusions, which in turn might influence policy and player safety. This study encourages a shift toward directly measuring actual concussion history instead of relying on assumptions that certain players are at higher risk of negative outcomes than others.

If career length and primary position aren’t good proxies for cumulative brain damage, what might physicians measure instead?

Directly assessing concussion history continues to be the best way to assess risk. Even though retrospective estimation of past concussions is not perfect, it tends to be the best and most consistent predictor of long-term health outcomes. Notably, a lot of our research suggests we don’t see significant declines in physical or mental health outcomes until someone has experienced 10 or more self-reported concussions in their lifetime. Other research also suggests symptoms at the time of the head injury could be a key predictor of long-term outcomes.

In the future, how could this new information be used to improve the quality of life of active or retired football players?

For retired players, it’s important to emphasize the message that a long playing career or playing in a certain position does not suggest you will have negative health outcomes. We want to help players avoid unnecessary worry about their long-term health. For active players, we need to continue our focus on accurately identifying and documenting concussions. This will help identify players who truly need follow-up care and better inform long-term monitoring programs that follow players across their careers and into retirement from football. We ultimately want to drive toward care that is proactive and rooted in the player’s actual health and symptoms rather than speculation or fear.