The differences in a brain affected by chronic traumatic encephalopathy and a normal brain.

Credit: Medindia

New Study Shows Prevalence Of CTE In Football Players

July 25, 2017

Barbara Howard: A stunning statistic out today regarding a brain disease that's closely associated with football players: Chronic Traumatic Encephalopathy, or CTE. CTE can only be diagnosed after death. The brains of 111 NFL players were studied and CTE was found in all of them except one. That is a rate of over 99 percent. The study was conducted by Boston University School of Medicine and the VA Boston health care system, and it's out today in the journal of the American Medical Association. One of the authors is Dr. Daniel Daneshvar from BU's CTE center. Thanks for talking with us, Dr. Daneshvar.

Dr. Daniel Daneshvar: Thank you for having me, Barbara.

Barbara Howard: So 111 NFL player brains and all but one was CTE. Was that a surprise to you?

Dr. Daniel Daneshvar: Yes. We've been studying this disease for about eight or nine years at the Boston University center and we'd been finding a high proportion of CTE in individuals who play a lot of contact sports, be that NFL or hockey or other sports. What we were particularly shocked to find, though, was that so many of them had CTE over a relatively short time period, the eight years of the study window.

Barbara Howard: So to a layman's eye, when you're looking at a brain sample, how is a CTE brain different from a healthy brain? 

Dr. Daniel Daneshvar: One of the reasons why the disease has gone under the radar is that a normal brain and a brain with earlier or moderate stage CTE — to the naked eye — is really relatively undistinguishable. It's only when you stain for a specific abnormal protein called tau that you can detect the evidence of CTE. This tau protein is in a number of neuro-degenerative diseases, including Alzheimer's disease, but when it's in a specific pattern, that's diagnostic for CTE.

Barbara Howard: Well, it does present itself sometimes as diseases associated with aging, for example, Alzheimer's disease. Also, there's a high rate of suicide that's associated with CTE, and some of the brains that your research team had access to came from NFL players who had committed suicide, and some committed suicide in ways that seemed meant to preserve their brains. Former New England Patriot Junior Seau comes to mind — he shot himself in the chest. It seems like some of these players suffering from CTE know that something is wrong with them, but they can't figure it out. What's your thinking on that?

Dr. Daniel Daneshvar: I think you're exactly right. A number of these individuals, be it at the NFL level or folks who only played through college or even high school, when they start to get advanced in age, they begin to develop problems with memory, problems with concentration, at an earlier age than they otherwise might have, and as a result, they can kind of tell something's wrong. That can be incredibly disconcerting for these individuals and unfortunately, some of them did end up taking their own life. The important thing about this study, though, is that we're hoping to bring this cohort together and from them, in this comprehensive and methodologically rigorous way, begin to answer questions for living athletes. 

Barbara Howard: Like, should I play football? That would be a question obviously raised — what do you think?

Dr. Daniel Daneshvar: At this point, we can't really make statements regarding what types of hits to the head are responsible for CTE or whether or not there's a relationship with how early you start playing football, or any genetic factors or other factors that might influence those decisions about whether or not an individual should play football. We're hoping that using this cohort, and by literally doubling the number of CTE cases in the world's literature through this cohort, we're hoping to be able to answer those questions. 

Barbara Howard: And by this cohort, you're talking about this particular study. Now, you're talking about 110 of 111 NFL players found who have CTE. In other parts of your study, 48 of the 53 brains studied of college players — that's 91 percent — were found to also have CTE. And in high school players, the rate drops down to 21 percent — three of 14. Is that only because you can't get a large enough sample?

Dr. Daniel Daneshvar: We necessarily have a skewed sample simply because the individuals who choose to donate their brains to our center, either they or their loved ones are more likely to think that there's something wrong, and that's why they chose to donate. That being said, there were individuals who did not have any symptoms that chose to donate to our study over the years. We know that individuals in this study are more likely to think that they have a problem and that makes the sample biased in that way.

Barbara Howard: It does seem like that would skew the result if you have the families of players with these symptoms already in life donating brains — it's sort of already predetermined, isn't it?

Dr. Daniel Daneshvar: You're exactly right, in that the individuals who choose to donate, they're more likely to have had problems. But that being said, we didn't screen athletes based on whether or not they had problems in life. The only inclusion criteria for this study were based on whether or not someone played football. It certainly is more likely to be biased for those reasons you just mentioned, but what we can say is that we found 110 NFL players with CTE over just an eight-year time course. That indicates that this is a significant problem.

Barbara Howard: And 91 percent among college players, but why 21 percent among high school players? 

Dr. Daniel Daneshvar: I think that we need some additional research to really understand the extent to which the duration that someone plays football and may be exposed to repetitive brain trauma, the extent to which that relates to their risk of developing CTE. At this point, we can't really answer the question about whether or not there is a relationship, but we're working on it.

Barbara Howard: It's very clear that this problem faced by players is at all levels of football — is there a way to make football safe?

Dr. Daniel Daneshvar: So at this point with this study, we're unable to say for sure what types of hits to the head increase your risk to CTE. But, I think there are some common sense things we can do to make football safer. I can't really say at this point whether or not we can make football completely safe, but what we can do is eliminate some of the unnecessary repetitive hits to the head, and that will likely decrease the risk of CTE. Unfortunately, at this point it's a little too early to say. 

Barbara Howard: If you had children, would you let your child play football?

Dr. Daniel Daneshvar: I played football in high school — I wrestled in college and got some concussions there, and I think I'm more or less cognitively intact so far. I think the important thing is to try and make the game as safe as possible with the information that we have. In terms of whether or not I'd let my kid play — I think in its current form, I probably wouldn't. But, I think there are some ways we can make the game safer, and I might change my mind in the future.

Barbara Howard: Thanks for joining us, Dr. Daneshvar.

Dr. Daniel Daneshvar: Thank you Barbara, it was a pleasure.

Barbara Howard: That's Dr. Daniel Daneshvar from Boston University's Chronic Traumatic Encephalopathy Center. He is the co-author of a study on CTE that came out today in the journal of the American Medical Association. That study shows that of the 111 brains that were examined of dead NFL players, 110 showed signs of CTE. This is All Things Considered. 

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