NFL Study of CTE: The Issues

In this episode of "In the Interim…", Dr. Scott Berry examines three recent health-research headlines through a statistician's lens: an Adventist Health Study-2 analysis claiming eggs reduce Alzheimer's risk, an Emory University trial on high-dose vitamin D and cognition (Zhao et al.), and a British Medical Journal study led by Dr. Daniel Danishvar (Harvard, Boston University) reporting that 25 to 97 percent of deceased NFL players showed evidence of chronic traumatic encephalopathy (CTE). After flagging multiplicity and small-sample issues in the first two studies, Scott spends most of the episode on the CTE study's central flaw: because CTE can only be diagnosed after death, the published prevalence is calculated from a sample of deceased players rather than the full population of NFL players — a distinction he illustrates using a thought experiment on sudden infant death syndrome (SIDS) and a breakdown of the study's own age-stratified death data. He traces the resulting bias, a form of differential mortality, to a single caveat buried deep in the study's limitations section.

Key Highlights

• Adventist Health Study-2's "27% fewer Alzheimer's diagnoses in egg-eaters" finding, and why it's likely multiplicity-driven and observational, not causal.
• The Emory University vitamin D study (Zhao et al.): a 13% MoCA improvement drawn from roughly eight patients, presented as a headline finding.
• The British Medical Journal NFL CTE study (Danishvar et al., Harvard / Boston University): a headline prevalence of "25% to 97%" of NFL players.
• Why 215 of 235 donated brains (97.7%) is a hugely biased numerator — CTE is only diagnosed posthumously, and families of symptomatic players are most likely to donate.
• The corrected denominator: 878 NFL players who died between 2016 and 2021, yielding roughly 24.5% — still biased, because CTE itself accelerates death.
• A SIDS thought experiment showing how building a "population" from those who have already died systematically overstates prevalence through a form of differential mortality bias.
• The key limitation, buried three-quarters of the way through the paper's limitations section, quietly mentions the selection bias behind the headline number.

For more, visit us at https://www.berryconsultants.com/

Creators and Guests

Host

Scott Berry

President and a Senior Statistical Scientist at Berry Consultants, LLC

What is In the Interim...?

A podcast on statistical science and clinical trials.

Explore the intricacies of Bayesian statistics and adaptive clinical trials. Uncover methods that push beyond conventional paradigms, ushering in data-driven insights that enhance trial outcomes while ensuring safety and efficacy. Join us as we dive into complex medical challenges and regulatory landscapes, offering innovative solutions tailored for pharma pioneers. Featuring expertise from industry leaders, each episode is crafted to provide clarity, foster debate, and challenge mainstream perspectives, ensuring you remain at the forefront of clinical trial excellence.

Judith: Welcome to Berry's In the
Interim podcast, where we explore the

cutting edge of innovative clinical
trial design for the pharmaceutical and

medical industries, and so much more.

Let's dive in.

Well, welcome back everybody
to "In The Interim."

I'm your host, Scott Berry, and
here on "In The Interim" we discuss

all things clinical trial science.

And as you know, we, we, we stray into the
world of sports and the lessons of data

analysis that things in sports teach us
about, things about clinical trials, about

medical modeling, medical decision-making.

So today, we are gonna talk about a study.

Uh, it does w- move into
the world of sports.

So I wanna introduce today's
topic more going back and telling

you a little bit of story.

Um, it's not a, uh, it's not
necessarily an appealing story about

myself, but I, I remember being at
my son, my son Cooper, he's, he's my

fourth child, um, and he's currently
a division three baseball player.

But back in, I think he was
13 years old, and we were at

a tournament, and I, I, I…

Well, let me, let me tell you the
story, then I'll come back to this.

So we were ahead in the game
something like 14 to nothing.

The game was at hand, we were winning
the game, and a play happened on the

field where the infield fly rule was
called, and it was called incorrectly

by the umpires And I got frustrated
and, and by the way, I, I am…

I, I don't think I'm your
typical Little League dad.

I don't say a word when my son is playing.

I don't say a word about judgment calls.

Uh, rules, I, I can say a word.

So I, I was, I was sitting back.

I also don't sit close to the field.

I tend to be way down the right
field line, but I was, I was

with a, a number of dads there.

And oh, I s- oh, that's not right.

They called it wrong, and all that.

And one of the dads turned to me and
said, "Scott, we're up 14 to nothing."

But it was, it was, it was getting
the rule wrong that just sat with me.

Now, there's an interesting
history of the infield fly rule.

First of all, what is the infield fly
rule, for those of you non-baseball fans?

Uh, it, it is a rule that
historically, I think non-baseball

zealots kinda know but don't know.

And so the infield fly rule is there
because in baseball, if you're a

base runner, and there are three
bases, if you're a base and the

ball is hit in the air and it's
caught by a fielder, you can't run.

You can't run until the ball is
caught, then you can try to run.

So if you were to take off and the ball
is caught, they can throw to the base

you were previously at, and you're out.

So if you're at a game and the ball
goes up in the air, largely the fielders

will hang out near the base to make
sure that they don't get doubled off.

Now, if you're in a situation where the
bases are loaded and the ball goes up

relatively in the infield, the infielders
could on purpose drop the ball, 'cause

you have to hang by the base, and then
they could throw it to the different

bases, and they could get multiple
outs relatively easily, and it would

be kind of an ugly play in baseball.

So there's a rule when there are at
least two runners on that, and there

are less than two outs, where you could
get multiple outs relatively easily,

that the infield fly rule is called,
and the batter's automatically out.

Now, there are certain things,
like the fielders can run at risk.

They can go thinking
the ball's gonna drop.

But even if the ball is dropped, that the
hitter is out So interesting going back

to seventh grade, I remember being…

It's weird how you remember
these, these little things.

I was just starting
baseball in junior high.

We had a junior high baseball team.

They don't do that anymore.

Um, and we were learning rules, and
I think largely the team was goofing

off, and the, the coach got frustrated.

So he points me out.

I'm sure it wasn't me, uh, goofing off,
but points me out and says, "All right,

Scott, tell me the infield fly rule."

And he clearly wants to embarrass me,
clearly wants to embarrass the team,

and I suspect he probably would've
made the whole team run I, I come

from, my father's a huge baseball fan.

His father was one of these, uh,
people that watched every single

Red Sox game or listened to on the
radio for many, many, uh, decades.

Huge Red Sox fan.

My dad's a big fan.

We're, we are, we are, uh,
pedantic statisticians.

I knew the infield fly rule exactly,
and I, I presented the infield fly rule.

When there are less than two outs and,
uh, at least first and second base are

occupied, the batter's automatically
out and the runners can run at risk.

You know, almost verbatim the rule, and
the coach looked rather stunned that his

whole thing of trying to make the team
run and all that didn't really work.

So I, I know the infield fly rule,
and it's almost a little bit of being

overly, uh, o- on the rule and maybe
the situation there of being 14 to

zero, uh, w- was a time I shouldn't
be quite so frustrated about the rule.

But maybe that's a little bit
about being a statistician as well.

Maybe the coach at that time should've
said, "Uh-oh, there's a statistician

in the making there," uh, within it.

And there are multiple triggers
like this, and my family knows, I

mean, people at Barry know certain
thing that trigger me, and getting

the infield fly rule is something
that certainly triggers me on this.

So okay, what, what does that mean?

Well, I-- this week I, I, I
get up early for breakfast.

So what is, what is my morning routine?

Uh, I've talked about multiple times
on here I'm not a great sleeper.

I work really, really hard to sleep well.

I think it's an important part of health,
important part of stress, number of

things, but I just can't do it very well.

I, I have a, I have a Whoop band,
and I average maybe six fifteen, six

thirty working really hard to sleep.

I wish, I wish I could sleep like
my wife who, who sleeps well over

seven, seven and a half, eight hours.

She's a gifted sleeper.

But I get up very early and, you know,
even the dog looks at me like, "Really?

You're, you're already up?"

And doesn't get up.

Um, I have a nice cup of coffee in
the morning, and here at the lake, uh,

on, in the little cabin here, I get to
sit out in the beautiful, uh, weather.

And by the way, I make my own
homemade muffins at zero sugar.

So I make essentially
kitchen sink muffins.

I put, uh, whatever I can find in
the muffins, and I make very large

muffins, and I have one every morning.

And I read the news of the
day And, uh, box scores, uh,

uh, political news, economic.

You know, I wanna be caught up on the
day, and it's a way my morning starts.

So, uh, earlier this week, I sit down
and I open up, uh, a, a news app, and

come blurting out at me, and I'm sure
it's targeted to me that I tend to

click on these, is the headline, "A
landmark study demolishes everything

we know about cognitive decline."

So I've done a lot in Alzheimer's
research, uh, uh, cognition studies.

Uh, partly it's why I, I, I
wanna sleep a little bit more.

I do think it is related
to brain health as you age.

Um, so I'd like to sleep as much as I can.

So I think it's important.

I do think some things
are related to this.

Now, it's demolished everything
we know about cognitive decline.

So of course I click on it, which
means I'll probably later get

more and more of these studies.

"A landmark study demolishes everything
we know about cognitive decline."

So it's actually a relatively large
study, 40,000 men and women 65 and

older, the Adventist Health Study-2.

And they did a study of, uh, of
participants, and they, uh, these were

Seventh-day Adventists, apparently
who have better, better health

generally, better diets generally.

And they do a survey, and they
took 40,000 that had-- did not have

cognitive decline at 65 years old,
and they did a 15-year study looking

at, uh, diagnoses of Alzheimer's.

So 2,800 of these patients were
diagnosed with Alzheimer's eventually.

And they recorded-- Part of the
story is they recorded a huge

amount of information about diet.

And they found that those eating five
or more eggs per week, um, at least

five eggs per week, had a 27% reduction
in the incidence of Alzheimer's

Non-randomized trial, uh,
certainly, uh, in this scenario.

What you don't get as well is
hugely multiplicities to this.

They recorded huge amounts of diet,
and they found this relationship.

Uh, they even found a relationship
that if you had less than five eggs per

week, you had, uh, two to four, there
was a 17%, uh, decrease in Alzheimer's.

I don't believe it at all in this setting.

That what we know about Alzheimer's
in this situation, this is very

likely multi-multiplicity driven.

It's not randomized.

People who eat those sort of eggs
are dif-different than, than not.

So it…

this landmark study demolishes
everything we know about cognitive

decline and just completely dismissing.

I don't believe it at all.

The next one that pops up, so this
is still, uh, that one goes and okay.

Another one is high-dose vitamin
D Um, may improve cognition

among those at risk of dementia.

This is Zhao et al.

It's in ScienceDirect.

It's actually labeled October
2026, and it's August 2026.

But this is a Emory University
study that suggests vitamin D

supplement intake may be associated
with better cognitive function.

So it's really interesting because
I've actually read a number

of studies about vitamin D.

I have low vitamin D.

And, um, uh, largely none of these
studies seem to show any effect of

vitamin D, whether it's in the intensive
care, in other settings, that it really

seems that taking these supplements…

So, okay, here's
cognition and Alzheimer's.

The study is 54 adults with sleep
deser- disturbances and MCI, and

a subset of them take high dose,
five thousand international units

of vitamin D daily, and it showed a

13% higher scores on the MoCA.

This is a cognitive test
with a p-value of .039.

Fifty-four subjects, and I almost
paid the $40 to get the article

to see what the sample size was of
those that took high-dose vitamin D.

It's gotta be, like, seven or eight.

Sorry, I don't have access to it.

I probably have access as an adjunct
faculty, uh, at Kansas University Medic-

Medical Center, but I, I didn't do it.

In part, I'm, I was looking for
it to see if I could find it.

Again, I don't believe this at all.

Um, I don't believe it's associated.

One of the conclusions from the authors
was this deserves a large confirmatory

trial to identify whether this is
real, this thirteen percent effect.

I don't believe it at
all, uh, in the setting.

Again, it's, it's non-randomized,
it's observational, multiplicities.

It's probably eight patients
out of fifty-four and a thirteen

percent difference in the MoCA.

Um, it just, just belies anything
believable, and it's bad science.

And so it's not uncommon
these things come out.

And by the way, I can't help but
say, "Oh, this is hugely problematic.

I don't believe it."

Many of you may be in the same situation.

It's not often I hear, uh,
complaints that, you know, you

think you know everything and, uh,
uh, in this setting, and I don't.

But I do know these are not good studies.

So I'm sitting there and a banner
comes up on my phone, and it's from

ESPN, so I do get banners from ESPN.

And the banner comes across.

It's partly why I didn't go
get the sample size for that.

All of a sudden, this banner
shows up early in the morning

And i-- the banner says 25% of
NFL players have evidence of CTE

Um, and so CTE is chronic
traumatic encephalopathy.

It is, uh, um, a damage to the
brain largely thought about

multiple hits, trauma to the brain.

I think it can be caused
by a number of things.

By the way, estimates of a
healthy population, non-boxers,

athletes, NFL players, it's a 0.6%

somewhere.

I don't know how well that's created
or what studies got that, but I think

the incidence of CTE is relatively low.

So 25% is wow.

That, that, that's huge.

So now, okay, this is an NFL study.

By the way, this study was
not funded by the NFL at all.

Partly I was gonna criticize the NFL.

You know, I mean, this is
the National Football League,

enormous amounts of money.

Let's do the, the, the study.

Well, as, as getting there, not
surprising you, I, I'm probably e-

ending up here criticizing this study,
but this, this study, the lead author,

Daniel, uh, Danishvar, is Harvard, Dr.

Daniel Danishvar, and it's a
whole group at Harvard, Boston

University, uh, a number of groups
here, biosti- uh, statistics and

epidemiology, uh, Boston University.

So this is, this is high quality
research, so I'm excited.

I wanna read this.

This is stunning, actually.

Part of it is now the, the,
the banner says that 25% of NFL

players have CTE or greater, 25%
plus, and then the first headline,

it's between 25 and 97% have CTE.

Again, this is, this is somewhat shocking.

And a quote, they quote
the lead author, uh, Dr.

Danishvar says this, um, the
estimate is 25% is on the low

end, and it's between 25 and 97.

The true rate is somewhere in the middle

So I'm pretty excited, and so I get the
study, and by the way, im-immediately

there's a number of comments, and this
is all 25%, uh, of NFL players have CTE.

So I get it.

It's published in the British
Medical Journal, uh, a wonderful

journal, uh, August 20-- uh, uh,
25th of August, I believe, 2026.

And what is this study?

So initially, a number of former
NFL players and their families

have donated brains for research,
and it's neurological research,

but it's largely research on CTE.

This is something we've been hearing
about for 10 plus years, and there

have been a number of high-profile NFL
players that suicide is not unusual.

Maybe they, uh, have huge cognitive
decline, number of issues.

They die early.

Uh, very problematic family issues.

Um, and, uh, so this is a, a huge
amount of research going into this.

The NFL is very interested in this.

A huge number of safety
precautions are now taking place

during games for head safety.

I think many sports in this.

Um, and so many former players have
donated their brains to research,

and CTE is only diagnosed upon death.

Uh, it, you-- it's a brain, uh, um, uh…

A look at the brain, uh,
posthumously, and the, um

338 former players have
donated their brains.

315 of those, 93%, had CTE.

That's not super surprising.

This is about CTE, and so families
with high risk that their, the players

had CTE, they're having neurological
issues, they donate their brain.

And so, uh, 93% of them had CTE.

That's not the, the estimate.

So it's clearly recognized
that's very biased in it.

So they focus on the years 2016 to 2021,

where the donation rate was the highest.

In there, 235 of the brains were donated.

Um, w- the, the player died between
2016 and 2021, those six years.

And of those 235, 215, which is, uh, 97.7%

of them, which is a number you'll
see in the headlines, uh, have CTE.

After death, um, they are examined,
and they are diagnosed with CTE.

There's grades of CTE, and you
can read about that in the paper.

It's…

That, that's talked about.

But, uh, 215 out of 235, so 97.7%.

So they do a case control study,
uh, whi- which is great, and

they have these 215 patients.

They're gonna focus on 2016 to
200-- 2021 because that's when

most of the donations happened.

That's fine.

Uh, I, I don't think that's an issue.

What they do is they go back,
and they go back to players

that played 1950 and later.

And you can go back and get every
NFL player that has played, and you

can go look for, uh, time of death.

Are these players still alive?

And you can get deaths,
uh, from these players.

So they identify in that set of
NFL players after 1949, which

is when helmets were mandatory,
um, after 1950 they played.

They found 878 players died
between this period of 2016 to 2021

So where does this 25% that shows
up in the banner, the headline

of this ESPN story, is 800…

Is 215 out of 878, is this roughly
24% that of players that died.

And so of all the players that died, 215
they know had CTE during this period.

And so that's where they say, "We
don't know what the, the highest is."

The highest is 97.7%,

uh, which is sort of a
fictitious high number.

It was the, the brains
donated within that.

But 215 out of the, the, those that
died in that six-year period, 878,

so of the 878, the 215 are included
in that, that it's 24%, uh, of that.

So that's a minimum because
some of those not in the 215,

they were never tested for CTE.

So of the remaining, what, 663,

that surely there's more CTE in
there, and no doubt there is.

Um, maybe it's the 0.6%.

Uh, we don't know what it is, but
hence this lead and, and the lead

author saying it's between this 24.5%

and 97.7%.

And then that's what's grabbed
by ESPN and is said to us

No

What's the issue, um, uh,
in this, um, uh, from that?

Um-

They, they recognize the
97% is hugely biased.

That we'll, we'll talk about the
two-- 215 in that, 215 is biased.

So they need to n- they need to have
a denominator that, that's numerator.

And I know there's prob- there, there are
more in the numerator than that 215, and

that, that's what they don't know without
fully doing an autopsy after for, uh, CTE.

So of that, they need a denominator.

So what's the appropriate denominator?

Well, this is a huge thing.

So what they do for the denominator
is they get everybody that died during

that period that were NFL players

So of those that died during
that time period, it's the 25%.

But that's not the denominator that
every single ESPN story, every single

talk show, everybody wants to know
is if you play in the NFL, what

fraction of tho- those players get CTE?

It's the

proportion that died in that
period that had CTE Okay.

Is that different?

Are those two things different?

And they certainly are different.

So their denominator's number of deaths…

Now, I, I'll, I'll describe a little bit
h- what the paper's conclusion says, and

they walk this fine line, uh, within it.

So they take a sample of players that
played after 1950 in this, and they, they

look at the number of deaths in there.

Now, if, if you have…

Uh, they, they don't go
back to the beginning of it.

If you had everybody with 100
years of exposure, those two

things can end up being the same.

If you ran a clinical trial and you
waited till everybody died, and you say

the proportion of those in the treatment
group and the control group had, uh, this

25%, then that, that's a reasonable thing.

Those are one and the same.

The denominator of the proportion
of humans or NFL players is

the same with those that died.

But when you take a sample of players
that have died before everybody has died,

the question is, is CTE related to death?

That estimate assumes that
they're entirely independent.

If CTE speeds up death, and it surely
does, the whole aspect of this is

if you have CTE, you're surely…

The, the, the lifespan
is, is clearly shorter.

And now we take individuals where
if you're 20 to 29 years old and

you end up in this sample and have
CTE, the proportion of those that

die of other causes is, is much,
much lower, and the proportion that

have CTE is incredibly increased.

Those e- even up to 60 or 70 years
old, that's going to be increased.

And so you accelerate deaths
that end up in the numerator

but not in the denominator.

They actually have a table in there of, of
those that are 20 to 29 years old, there's

nine of them in the sample that had CTE.

Very, very early death.

17 died that did not have CTE.

So that kind of ratio in the
samples is about one-to-two

In the 90 to 99 age group, there were
two in that sample that died of CTE

at that very, very late age group,
45 that were not in that age group.

It's a ratio of 2-to-45 in that
for that particular age group.

That repr- that, um, ratio
holds the whole way through.

It's 60-to-400 in the 80 to 89 group.

It's about one-to-seven in that
group, where it's one-to-two

in the earlier groups.

CTE accelerates death, it gets you in the
sample, and they start at a particular

age where they only take people ab- above
and beyond that landmark time period.

Let's take a extreme of this.

Suppose I was doing a, a…

And I wanted to know the lifetime risk
of SIDS, sudden infant death syndrome.

Largely, I, uh, I, I don't know this
disease very well, but I, I don't think

you get SIDS beyond eight years old, say.

And we take everybody born after
2020, and we look at, uh, all those

that have died since 2020 of SIDS,
and then we looked at e- every other

human in that sample that has died.

It's a relatively low death rate in that.

And we look at what proportion
of them die of SIDS, and we

say that that proportion is the
proportion of humans that have SIDS.

Horribly biased.

Uh, it's a really, really bad estimate,
probably hundredfold different than

what it is, if not even higher,
because you accelerate if you…

Sudden infant death syndrome, they, they
die of SIDS, it accelerates that, and

dying of other causes in that scenario
where then they don't have SIDS in that,

that setting, the denominator of deaths
when you've got this lower horizon in

the proportion, you accelerate those
that die of, of SIDS in there, and your

estimate is not The proportion of humans
that have SIDS, it's the proportion of

those that die young that have SIDS.

Those are very, very different things.

They're, they, they're
They're not comparable.

Well, that's what this NFL study is.

It has a higher proportion of those
that die early in that group of CTE.

You can write out a simple
tree diagram of dying early,

presence of CTE in all of that.

So what is this 25%?

Well, it is inflated by sort of the
ratio of the probability of death early

given CTE to the probability of death
early given no CTE That is substantial.

Now, the number of players that played
like in the 1950s, many of them probably,

uh, die in that period and all of that.

But the proportion of those from the 1950
per- period, um, uh, uh, is much less in

the CTE group, which you have those that
are younger is higher proportion of there.

Again, this same bias within that.

This is substantial.

I don't know, maybe this is
four or five times as great.

They have reasonable exposure.

If you did this study, everybody
that p- uh, played after 2000,

this would be a much higher bias.

They could do that in the data, and
it would be a much, much higher bias.

The proportion of those is
gonna be very, very high.

Uh, you know, they're get
60% or something like that.

And so each time you go back and draw
that line at different times, it's

also that the NFL, there are many more
players that have played recently than

played in nine- in the 1950s or '60.

So this ratio of death early given CTE
to death early given no CTE, maybe five

times in this setting, which takes that
25% and maybe it's 5%, maybe it's 8%, 10%.

The point is their lower bound of 25%,
the bottom level, I don't believe it.

Uh, it, it, it's gotta be lower than that.

Now, the other question
is: What is the numerator?

What are the proportion of those that
don't donate their brain that died in

that particular time period that had CTE?

We don't know what that rate
is, um, uh, within that setting.

How many more of those?

And that's kind of the unknown.

So we have an unknown numerator, we
have an unknown denominator, and they're

trying to attach a, a number to this.

I think they'd have been much
better had they gone back and tried

to do this as a Kaplan-Meier type
aspect of it with missing data

and try to estimate these biases.

I think would've been a more
appropriate way to measure this.

So again, uh, uh, you know, th- thinking
about this, the, this particular scenario

and their, their conclusions, by the way,
let me try to get their conclusions here.

Um-

Sorry.

I, I should, I should have this set up.

Their conclusion, um, is, and I'll, I'll
read it, I have the paper right here.

"The findings of this study are that
at minimum, nearly a quarter of all

NFL players who died during 2016 to
2021 had CTE neuropathology at death."

It's, it's correct.

Um, in that setting, it's
a meaningless quantity.

It, it, it's a meaningless quantity
because you, you have more deaths

in there from CTE than you would
otherwise because they die earlier.

So it's correct.

It's a number.

It's a statistic from the trial.

They knew full well this was gonna
be interpreted that prevalence

of NFL players is 25%, which
I think is, I think it's bad.

Um, you know, I was gonna say, you know,
I'm criticizing this enormous NFL thing.

Maybe it's worse criticizing
these investigators from Harvard,

Boston University and this.

But this is misinterpreted, it's misused.

That's bad.

Now, going back to this infield fly
rule, is this Scott being too technical?

Is it 14 to nothing, and Scott's
pointing out a, a, a bad call, a

misjudged rule, when the major picture,
I have no doubt that playing football

for 25 years, high school football,
college football, NFL, increases

your chance of CTE substantially.

So this is, this game's 14 to
nothing, um, uh, within it.

I didn't let my children
play tackle football.

I, I did in junior high, and I
actually I finessed the system.

So I, I started this with my son
Cooper, who now plays college baseball.

So good athlete, grew up in Texas.

There's a lot of incentive,
social incentive to play football.

He wanted to play football in
third, fourth, fifth, sixth grade.

They, they have a really good
tackle football league there.

I wouldn't let him play.

His mother wouldn't let him play.

I wouldn't let him play.

So I believe this, this is a thing.

Interestingly, we got in seventh
and eighth grade, we thought

it was a really important part,
and we, we allowed him to play.

We had him go out and pushed him to
go out for quarterback, good athlete,

good arm, because we knew there were
three players ahead of him, and one of

them is playing college football now.

Another one was a Division I lacrosse
player, and I think the third one ended

up playing Division I college baseball
as a tremendous athlete at the time.

We knew he was gonna play third team.

We knew he wasn't beating out
any of the three, and he did.

He played on the C team which was a
glorified pillow fight, where there

were, there were men that played seventh
grade football, uh, on the A team.

So he played every play of every game,
had a blast, uh, and was relatively safe.

He quit after his eighth
grade year in that.

So I believe the score is 14 to
nothing here This causes CTE.

So me being critical of this study, is
it me being the pedantic statistician

that, okay, this is a technicality?

I don't think so.

I, I think this was meant
to supply information.

And if somebody's taking this into
account and making a decision, which I

know can be a horribly difficult decision
for an 18-year-old to decide the riches

of a potential NFL career with the,
the risk of head injury and potential

CTE and the downline parts of it.

But if you're providing the wrong
number to this, and by the way, they

state in this that this number is
substantially higher than other studies.

So I don't know what it is,
but 25 isn't the minimum here.

Maybe the minimum is eight, but
that's the thing you need to know

is the relative proportion of that.

So very bothered by the study.

I-- so I decided to go in and look
at, there's a very large section

here of, of study limitations.

Most of it talks about, uh, the
observational part of it, much like the

other two studies, and which I think
has a relatively small part to it.

But hidden in there within a page of
limitations, about three-fourths, there's

a sentence that says, "Also, because
CTE can only be definitively diagnosed

at death, and dementia is inherently
a condition of living individuals,

assessing each after death restricted
the study population to decreased

NF-- uh, to deceased NFL players
and introduced potential selection

bias from differential mortality."

That's my, my whole point.

So it's a little sort
of caveat down there.

I gotta do limitations of the study.

This is enormous.

And there's, you know, a lot of times I,
I struggle with this because sometimes

biases are not very relevant, like, uh,
group sequential designs, early stopping,

the bias is relatively irrelevant, um,
in the overall grand scheme of things.

This is not, but it's put down
there as a minor thing, um,

that if there's a potential bias
from differential mortality.

So this was my morning coffee.

I got riled up early in the morning,
got these three studies, was my

usual sense of this, uh, my, my,
uh, uh, detailed part of this.

So I thought you might
be interested in it.

I appreciate you joining me today.

Thank you for joining me.

Until next time, we'll
be here in the interim