New Study Finds ‘Surprising’ Correlation Between Degenerative Brain Disease And Amateur Athletics


A 6th grade youth football game in Richardson, Texas. Some of the boys play with a new type of football helmet designed to reduce the risk of concussions. September 25, 2010

Chronic traumatic encephalopathy (CTE) is a brain disease that is most commonly associated with professional athletes, particularly NFL players. But new research performed on Mayo Clinic’s Florida campus suggests that amateur athletes are at risk of developing CTE pathology as well.

Over the past two years, scientists examined 66 brains from the Mayo Clinic Brain Bank belonging to males who had played contact sports when they were young. Evidence of CTE was found in 21 of those brains, an alarming 32 percent.

Researchers also examined 198 brains from the bank that belonged to individuals who had no documented history of participating in contact sports. None of those brains showed signs of CTE pathology.

These results were “very surprising” to Kevin Bieniek, the author of the study. “We’ve been so used to hearing about CTE in pro athletes, but this proves that [the disorder] is more common than one might think,” he told ThinkProgress.

CTE, which can only be diagnosed posthumously, affects mood, behavior, and cognition, causing everything from short-term memory loss and headaches to dementia and severe depression. It is believed to be caused by repetitive brain trauma, such as hits that cause concussions. In September, a study conducted by the Department of Veteran Affairs and Boston University found that a total of 87 of 91 deceased former NFL players tested positive for the brain disease.

But unlike the study done at Boston University, where the brains were donated by individuals and families who already suspected the deceased had suffered from CTE, the brains used in the Mayo Clinic study were willed over to the brain bank due to a variety of neurodegenerative disorders such as Alzheimer’s and Parkinson’s.

In fact, Bieniek had never even seen CTE until he stumbled upon the pathology when studying a case at the clinic. When he noticed that the individual was a former high-school football player, Bieniek was alarmed because of the prevalence of the disease among former NFL players. He began to wonder whether any other cases of CTE in the clinic had been missed because the doctors simply weren’t looking for it. So he searched through the files and obituaries of the 1721 brains in the bank, and found evidence that 66 had played contact sports at some time in their life — be it football, boxing, wrestling, rugby, basketball, baseball, or other sports.

“The 32 percent of CTE we found in our brain bank is surprisingly high for the frequency of neurodegenerative pathology within the general population,” he said. “If 1 in 3 individuals who participate in a contact sport goes on to develop CTE pathology, this could present a real challenge down the road.”

There are caveats, of course. Bieniek noted that while it is significant that the brains examined by the Mayo Clinic weren’t selectively donated for CTE research, there is an unknown correlation between neurodegenerative disorders and susceptibility to CTE. Also, the median age of death of the brains studied was 78, meaning that the men played contact sports decades ago when recognition of concussions was very limited.

“Contact sports have already changed so much compared to when our cases played,” he said. “There’s a lot of emphasis on concussions now. It’s a big step up.”

So while Bieniek doesn’t want to cause a mass panic yet, he hopes that this study will increase awareness that will result in more rules and regulations in contact sports that will help reduce head collisions, and help further research on the disease, so that eventually it can be detected — and hopefully treated — while people are still living.

“The goal is to create awareness that this isn’t a pathology solely restricted to pro athletes on TV,” he said. “High school and college players are susceptible to it too.”