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More on CTE and whether or not its even a diagnosable disease

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The Sports Skeptic is back to answer your questions and respond to your comments about his first piece on CTE and whether or not it's even a diasgnosable disease.


This is a guest post by The Sports Skeptic @sportskeptic on Twitter.

My last article exploring whether or not CTE was even a diagnosable disease generated a number of interesting comments. I thought it would be good to examine and address those comments. With an issue as important as this, I think its best to continue the discussion.

Re: The Tobacco Industry and Corporate Misinformation

"These type of arguments were used by the tobacco lobby for years. Some people smoke for years and don't get lung cancer. Other people get lung cancer who never smoked. Therefore, the data is very confusing! There are conundrums! Smoke all you want. Don't worry be happy!" -- Ptminotauro

This is an interesting comment. Not only is it a logical fallacy, it doesn't address any of the evidence. It simply uses a totally unrelated issue (smoking) and draws the conclusion that these were the same "types of arguments" used by the tobacco lobby. Except the poster never states what these arguments are. He just assumes that what the media has told him is that CTE is a confirmed diagnosis and all of the studies I cited are covering up for the sports industry. The key difference between the tobacco lobby and the studies I cited is that all of the studies I cited were from independent sources with no ties to sports.

Moreover, it is important to note, that scientists and researchers knew that smoking caused lung cancer for decades before the Surgeon General released its report in 1964. Independent doctors and scientists had argued that tobacco caused negative health effects as far back as the 18th century. The first report in medical journals to suggest a link between tobacco and lung cancer was published in 1912. The first formal studies showing a link were published in the late 1920s. By the 50's, there was a clear scientific consensus that smoking was an unhealthy habit that led to lung cancer and other diseases.

CTE, today, does not have that scientific consensus. There are genuine, legitimate questions regarding its existence by independent researchers. That is not to say that one day we will have conclusive evidence not only that CTE exists, but that repeated head trauma leads to it. However, we are not close to that day yet as the research I sourced outlined. Unlike the tobacco industry who insisted their product was safe, nowhere did I argue that concussions or brain trauma was safe.

More research must be done on brain injuries and concussions. The danger is that we have no way to diagnose CTE conclusively in the living, yet we see reports that Terry Norris and Tony Dorsett have CTE. It worries me and other researchers that doctors are just jumping on the diagnosis de jour and telling former athletes with any cognitive issues that they have CTE when those individuals could very well have another treatable issue. That is a real possibility with dangerous consequences for some of our sports heroes.

Re: Lifespan of Retired NFL Players

"Retired NFL players live longer than the average population"

Got a cite for this? Here's mine.

"The result is a dramatically shortened life span: While white men in the United States on average live to age 78 and African-American men to about 70, "it appears that professional football players in both the United States and Canada have life expectancies in the mid- to late-50s," Harvard researchers wrote in a summary of their project." (to be fair, shortened lifespan of an NFL player could be due to a number of factors (mentioned in the article I linked), not just head injuries)." - Pantherhare

The link cited above regarding the life span of NFL players, is not a study at all. It is an announcement of an agreement between Harvard and the NFLPA to research the health of NFL athletes over a 10 year period. The blurb about NFL players living on average two decades less than the average male It is simply an estimate that comes directly from the NFLPA. In fact, this is a long repeated myth that has been debunked.

Could the NFLPA have exaggerated that number? Possibly. Do they have any research to support that number? I doubt it. Do they have a reason to underestimate the life span of their athletes and repeat that myth? Absolutely, with the billions of dollars at stake, every penny counts. Unnamed Harvard researchers wrote that it "APPEARS that professional football players in both the United States and Canada have life expectancies in the mid- to late-50s," - This has yet to be studied by the researchers and they are simply repeating what they have been told by the NFLPA.

The citation in the article, on the other hand, is an actual study completed by National Institute for Occupational Safety and Health (NIOSH) at the request of the National Football League Players Association (actual study is here)with a large sample size of over 3,400 players.

It found that NFL players did live longer than the average male. This data has been consistent over the years. Here is an earlier version of the report from 1994 that showed the exact same thing: NFL players do live longer than the average male. Isn't it odd that the NFLPA commissioned these large studies that show their players do live longer, yet the article cited states that the NFLPA says their players live two decades less than the average male? Isn't it also interesting that this estimate has no citation, is a long debunked myth, and comes after an almost billion dollar settlement for some of its members?

Many people make the assumption that because football is a violent sport that its participants must live shorter lives, but the data shows otherwise. If anyone has an actual study of former NFL players with a large sample size and real data that shows otherwise (not just anecdotal evidence or an estimate from a group who stands to gain from a low life span estimate), I'd be happy to revise the article.

Re: "Science"

Beware of those whose only interst is "science"

When someone says, as above, that the CTE data is not "scientific". They are really trying to set up an impossible hurdle for the data. You can not legally or ethically do "science" on human beings. Here would be a great experiment. Take 2000 healthy college age males. Have them wear football helmets and then subject their skulls to some kind of blunt trauma, enough that they get KOd for few seconds. Now do this say twice a day for 2 years. Pick 200 at random and autopsy them, taking out and preserving their brains. Section their brains and look for Tau pathology. The next year do 200 more autopsies and repeat year after year. Then we will have some science! -


There are so many fallacies in this post. Its hard to pick a place to start. No one is arguing that CTE data is not scientific. Science is a process and each study adds to that process, in some cases, even those that are flawed. Through that process, we learn reality. Dementia Pugilistica (CTE's forerunner) was first coined and diagnosed in 1928. We have been studying this for over 80 years yet we still do not have definitive evidence that it exists, what the causation is for it and most importantly, virtually every major study has not shown a correlation between concussions and CTE.

Scientists do not set up an impossible hurdle for the data. The data leads them to find conclusions. The only people who set up impossible hurdles are those with an agenda or those who have already made up their minds on the issue. I raised legitimate questions regarding CTE, yet this poster does not address the evidence presented just attacks science. It seems that he has already determined his stance without an objective look at the evidence, exactly what he accuses me of doing.

I'm not sure what he means about when he says "You can not legally or ethically do "science" on human beings." Of course, you can. Scientists study human beings everyday ethically and legally. Many of our greatest scientific achievements like vaccines have come from this sort of research.

But most telling is that his "great experiment" would tell us nothing. It would be an exercise in futility. He states "then you would have some science" but the reality is that we would only have some data. We wouldn't know what the brains looked like in the normal population. We could examine the brains of 200 random college students that have had brain trauma, but without studying the brains of the general population that would tell us nothing. Its possible that the brains of the general population would mirror those of the college students.

Additionally, as I pointed out in the article, even if the college students brains showed a more advanced buildup of tau protein, we still would not know a few key factors:

  1. Did those college students with brain trauma ever show any signs of cognitive impairment?
  2. Assuming we tracked those who did have signs of cognitive impairment, did any of those show an excess buildup of tau proteins? and
  3. If they did show a buildup of tau proteins, were there any other factors that the affected group shared? (e.g, alcoholism, drug use, smoking, etc..) Even if all of those answers pointed to something like CTE caused by brain trauma, we still wouldn't have the answer of WHY tau build up causes those cognitive issues.

Re: Is CTE a disease?

When it comes to determining whether CTE is a disease, I think I'll trust the Center for Disease Control, the research department at Boston University, and the Journal of Neuropathology published by the National Institute of Health (PDF). - kemi.fuentesgeorge

It seems fairly clear that the disease exists. The authors do recognize that there is a danger in misdiagnosing it in living and dead athletes, but misdiagnosis is a risk in virtually any disease. The danger in intimating that CTE is overblown, is that it suggests that it is something less severe and less of a risk than merits attention.

The link given above for the CDC does not make any statement regarding CTE. In fact, it uses the same study that shows that NFL players live longer to show that NFL players may have a higher risk of neurodegenerative diseases. That study only could use Alzheimer's, ALS and Parkinsons as a measuring stick because those were what were listed on the death certificates of the players, not CTE. CTE was not listed on ANY player's death certificate. In fact, here is a list of topics/diseases that begin with the letter C that are indexed on the CDC website. CTE is not included.

In the study cited, 17 players had listed a neurodegenerative disease out of the 334 that passed away. That is about three times what would be expected in the general population. Is it something that warrants more study? Absolutely. Is it something that we should take as fact based upon a small sample size of 17? Absolutely not.

The Boston University study is also cited in the original article as an example of part of the problem. If you read the study, you'll find that there is a long laundry list of symptoms for CTE, none of them are specific to CTE. They could all be indicators of other diseases.

There are a couple of other problems with the Boston University study. The first is that is uses a very small sample size. I quote: "In this review, we present a summary of the 47 cases of neuropathologically verified CTE in the literature. We also report the clinical and immunocytochemical findings of CTE in 3 retired professional athletes, i.e. 1 football player and 2 boxers, ranging in age from 45 to 80 years."

3 cases in retired professional athletes! Seriously? Yes, that is what the study uses to come its broad conclusion.

And nsecondly, there is no control group. What do the brains of athletes or the general population look like? Is there a clinical diagnosis for the disease? No.

Lets look at what they wrote in the article in regards to the one football player:

"At age 40, his family began to notice minor impairments in his short-term memory, attention, concentration, organization, planning, problem solving, judgment, and ability to juggle more than one task at one time. His spatial abilities were mildly impaired and his language was unaffected.

Towards the end of his life, he tended to become angry and verbally aggressive over insignificant issues and was more emotionally labile. He also began to consume more alcohol, but did not show other signs or symptoms of depression. He had no significant psychiatric history and he had never taken performance-enhancing or illicit drugs. His family history was negative for dementia and psychiatric illness."

The evidence they cite in the paper itself is based on questions asked to him and on whether or not he could understand television. It also states he began to consume more alcohol. How much was he drinking before and how much was he drinking then? Can alcohol cause an increase in tau proteins? If so, where is that control group? Was this behavior consistent with a neurological disease or was it simply alcoholism?

Obviously, it is virtually impossible to draw a conclusion based on three case studies, but it is just as difficult to draw conclusions based on on subjective issues like short-term memory, attention, concentration, organization, planning, problem solving, judgment and multi-tasking. All of those are general issues that can be caused by numerous issues including depression or alcoholism.


Is CTE a real disease that one day we will be able to diagnose? Possibly, but that day has not yet arrived which is why we need to continue researching the subject objectively and without emotion. No one is arguing that repeated brain trauma is good for long-term health, what we all want is evidence that this trauma is causing a real diagnosable disease so that we might one day be able to put safety measures in place that help protect athletes' long term health without the danger of misdiagnosis and overdiagnosis, which seems to be the case today. That seems reasonable, doesn't it?