Five New Answers about the Link between Football, CTE, and Dementia
Five New Answers about the Link between Football, CTE, and Dementia
When it comes to our brain health, both gray and white stuff matter. The brain’s white matter is made up of all the connections linking together the brain’s working neuron cells, which are collectively known as gray matter. Traumatic brain injuries and concussions have long been known to contribute to white matter injury, which breaks down the connections between the brain’s neurons and is associated with dementia. But more recently, subconcussive repetitive head impacts—like the kind of hits experienced by football players—have also been attributed to causing white matter injury.
Now, for the first time, researchers from Boston University’s Chronic Traumatic Encephalopathy (CTE) Center have discovered a link between dementia, white matter, and the neurodegenerative disease CTE in former American football players. Published August 5 in JAMA Neurology, their study is one of the first to reveal the biological mechanisms that link years of playing football to white matter injury, which might contribute to dementia in people with CTE.
The Brink spoke with study lead researcher Michael Alosco, a BU School of Medicine assistant professor of neurology and codirector of the clinical cores at BU’s Alzheimer’s Disease Center and the CTE Center, to learn more about the connection between CTE and dementia. Here’s what we learned.
The Brink: Many former football players who suspect they have CTE—as well as their family members—have said dementia is one of the symptoms that made them concerned about their brain health. How does this study provide solid evidence that the dementia seen in CTE patients truly is caused by years of football play?
Alosco: CTE is characterized by an abnormal buildup in the brain of a protein known as p-tau. Consistent with some of our past findings, we found a greater amount of p-tau in the brain was associated with dementia and the number of years a person had played football. But one of the really cool and new findings about this study is the white matter piece. Scientific literature has long shown that white matter changes can be the result of traumatic brain injury and/or concussion. However, in this study, we found a direct association between the number of years someone played American football and the severity of white matter changes; the more years of football someone had played, the more likely they were to have more severe white matter changes, which contributed to dementia. Based on this study, we know that p-tau is not the whole story.
We also found other factors contributing to dementia in people with CTE that were not related to a person’s exposure to repetitive head impacts. Specifically, we found that arteriolosclerosis, a hardening of the brain’s small vessels due to cardiovascular disease risk factors like high blood pressure, also contributed to dementia.
Do these findings mean that football can directly lead to dementia?
It’s really the first study to bring together the buildup of p-tau, white matter changes, as well as arteriolosclerosis and link them all together as contributing to dementia in people with CTE. Years of American football play was indeed associated with dementia through its relationship with p-tau and the white matter changes.
From clinical interviews, you found that nearly two-thirds of the study participants, who were all diagnosed with CTE, also had dementia. Why doesn’t everyone who has CTE also have dementia?
We do see a lot of variability between individuals in how CTE develops and who gets dementia. Our study suggests that this is likely a result of several different factors that can affect people with CTE, such as a combination of p-tau buildup, white matter changes, as well as arteriolosclerosis.
What do these findings mean for the bigger picture of CTE research? Is this another huge strike against football?
Our study provides concrete support for the link between head impacts, white matter changes, buildup of p-tau, CTE, and dementia, bringing all these factors together into one story. But there’s still a lot left to do. There are important limitations to consider—we only looked at the brains of football players that have already been diagnosed with CTE. In that group, we looked at white matter brain disease using a subjective scale. What we really need to do is get more granular assessments of white matter to see the extent of white matter injuries and better understand the relationship between head impacts and dementia. We also need to bring in people from other comparison groups, such as looking at how people with Alzheimer’s might have a different white matter story than people with CTE. We expect, for example, that we would see more white matter damage in people with CTE.
Most importantly, although these pathology studies—where we are looking at the brains of deceased people—are really informative in terms of understanding disease symptoms and the biological mechanisms that cause them, we really need to have more longitudinal studies in living people—following someone throughout their life to see how symptoms change over the course of time. Some factors we’ve identified, like having arteriolosclerosis, could accelerate the course of CTE and make the symptoms more severe.
For you, what are the biggest takeaways from these findings?
P-tau is one contributor to CTE, but we need to consider what’s a consequence of that. How much of dementia and other clinical outcomes are due to tau, and how much to white matter changes or other factors like arteriolosclerosis? It’s a more complex story that we need to understand. We also have to be mindful of the limitations of this study—these findings can’t be generalized to look at the broader population since we only looked at former football players with CTE.
This work was supported by grant funding from the National Institute on Aging, the National Institute of Neurological Disorders and Stroke, a Department of Veterans Affairs Merit Award, the Nick & Lynn Buoniconti Foundation, the National Center for Advancing Translational Sciences, the Fonds de recherche du Québec–Santé, and the Alzheimer’s Association.
Why doesn’t every NFL player have CTE? So many ex-footballers seem to not be affected. Most of the media is hanging the NFL out to dry regarding this issue. I agree that the NFL has been non-cooperative and non-responsive to this important health issue, possibly criminally so. But there seems to be so many unanswered questions. The NFL doesn’t know. Doctors don’t know. Why does Mike Webster and Junior Seau get it, but Dick Butkus and Steve Young (7 concussions) do not. How much of the general population has or had CTE, so that we can compare? Their brains weren’t cut open to find out. The NFL is in self-preservation mode and I abhor their lack of morality, but I don’t know that we can go as far as saying that they are culpable for the premature deaths of some of these players. Again, why do some get it and some do not when they both have been exposed to the constant punishment over many years?
Regardless of why some do vs. don’t acquire CTE, I think it’s fair to say that there is sufficient evidence for parents to make informed decisions about their young children playing tackle football. I don’t think we can hold the NFL fully accountable – think about how many other sports have dealt with the same issue and not warned athletes, i.e. NHL, boxing, skiing, etc. People continue to poke holes at the science, but these reports should at the very least be screaming PSAs to the individuals who decide to continue playing after several concussions, rather than grounds to serve up lawsuits against corporations. Unfortunately, it is probably up to the athletes to protect themselves in the long run. New regulations and better helmets can only do so much.
Every dead football player who brains were examined post morteum had CTE. Not some…ALL. Junior Seau was sleeping in his car and in order to sleep he would use a tazer on himself. An ex chicago bear killed himself by shooting his heart but first calling ambulance to get there to get his brain out to prove the CTE findings and shot himself in heart just as they arrived…..he had it BAD. The NFL’s own findings say there is a linkage and made a 273 million dollar lawsit from former players. I am upset with myself that I coached for 10 years and let my son play. Talk to troy Aikman, Steve Young, ron lott Jim McMahon. Abg lifespan of NFL players is 25 years below avg male.
They only studied football players but there is nothing listed here that proves there is a higher frequency in football players than the general population. Also the equipment of today is so much more protective than the older equipment. Coaches are also much more aware of the importance of sitting out players who possibly have injuries. So looking at people who played 20 years ago isn’t necessarily indicative of players today.
My husband played 10 years in the NFL, he is now 44. The heartbreaking issues he’s struggled with the last 5 years
(which despite great efforts, only get worse) would scare anyone away from football. We have 4 children, and live daily on eggshells. He is very aware of the destruction he is creating, and doesn’t want to be doing it- but his emotional impulsivity problems respond to no meds, no therapy, no interventions. It is a confusing and scary process to watch, and one nobody can clearly call it CTE, which makes it even more isolating and difficult to deal with and understand. Trust me, the NFL needs to be held accountable. They continue to pull in billions while throwing pennies toward these men for the sake of saving their public face. The NFL world family is small compared to the general public, and therefore the public doesn’t hear from us enough. Fighting against the NFL and the damage they know is happening is like fighting against God- a God with a bottomless pit of money and lawyers.
I live in columbia sc , my son thinks that he has CTE and he is really struggling , Is there anyone that can help me help him in this area? He said that he really needs help and I am very worried.
My first husband played only high school football back in the 60’s. His team won a lot of games & he was known for his hard hitting. About 7 yrs after graduation he started exhibiting extreme impulsivity and mood changes and behavioral problems. He died in a motorcycle accident in 1978 & no one knew about CTE at the time so an autopsy wasn’t ordered. I’ve been haunted for many yrs as to why he changed so extremely overnight. So I was wondering if I could find more information on CTE in high school football or is there any school/university I can contact to read/contribute to their studies on the subject. I would appreciate any help you can give me. Thanks. 1/13/2022