At
least
one
in
four
former
National
Football
League
(NFL)
players
who
died
from
2016
to
2021
had
chronic
traumatic
encephalopathy
(CTE),
a
retrospective
study
suggested.

Among
all
NFL
players
who
died
from
2008
to
2021,
the
possible
prevalence
of
CTE,
a
disorder
associated
with
repetitive
head
impacts,
ranged
between
18.5%
and
98.7%,
reported
Daniel
Daneshvar,
MD,
PhD,
of
Massachusetts
General
Hospital
in
Boston,
and
co-authors.

Among
those
who
died
from
2016
to
2021
—
when
brain
donation
was
most
frequent
—
possible
CTE
prevalence
was
between
24.5%
and
97.7%.

Stage
IV
CTE
pathology,
indicating
the
most
severe
form
of
the
disease,
was
associated
with
symptoms
of
dementia
(risk
ratio
1.44,
95%
CI
1.16-1.78,

P<0.001),
the
researchers
wrote
in


The
BMJ.

“Community
brain
bank
studies
have
shown
that
CTE
affects
less
than
1%
of
the
general
population,”
Daneshvar
said
in
a
news
release.
“To
find
that
somewhere
between
24.5%
and
97.7%
of
NFL
players
from
that
time
period
had
this
progressive
brain
disease
is
a
wake-up
call
for
the
NFL
and
scientific
communities,”
he
noted.

CTE
can
be
detected
only
at
autopsy.
In
stage
IV
CTE,
phosphorylated
tau
pathology
is
widespread
across
cortical
and
subcortical
structures.

“Previous
brain
bank
studies
have
reported
a
high
proportion
of
CTE
among
former
contact
sport
athletes,
including
110
of
the
first
111
former
NFL
players
examined
at
Boston
University’s
UNITE
Brain
Bank,”
noted
Tobias
Kurth,
MD,
ScD,
of
Charité-University
Medical
Center
Berlin
in
Germany,
and
Richard
Riley,
PhD,
of
the
University
of
Birmingham
in
England,
in
an

accompanying
editorial.

However,
brain
donation
is
not
random
and
may
be
more
likely
for
players
who
had
neurologic
symptoms
when
they
were
alive,
Kurth
and
Riley
pointed
out.

“Daneshvar
and
colleagues
recognize
this
limitation,
and
their
work
advances
the
evidence
base
in
several
important
ways,”
they
wrote.
“Rather
than
reporting
only
the
prevalence
of
CTE
among
brain
donors,
they
identified
a
well
defined
source
population
comprising
all
former
NFL
players
who
died
between
2008
and
2021
and
linked
this
population
with
data
from
brain
banks.
This
allowed
the
investigators
to
estimate
plausible
lower
and
upper
bounds
for
CTE
prevalence
at
death
in
all
NFL
players.”

The
analysis
included
1,712
former
NFL
players
who
died
from
2008
to
2021,
of
whom
338
donated
their
brains
and
315
had
a
diagnosis
of
CTE.

Brain
donations
were
from
American
football
players
who
had
played
at
least
one
NFL
game
after
1949,
the
first
year
hard-shell
plastic
helmets
were
mandatory.
Most
donations
(333
brains)
were
to
the
UNITE
brain
banks
at
the
Boston
University
CTE
Center;
one
was
to
Mount
Sinai
in
New
York
City,
and
four
were
to
the
University
of
California
San
Francisco
Alzheimer’s
Disease
Research
Center
brain
bank.

Personal
information
and
causes
of
death
according
to
the
National
Death
Index
were
obtained
for
all
NFL
players
who
died
during
the
study
period.
Neuropathologists
who
were
masked
to
clinical
and
repetitive
head
impact
histories
assessed
postmortem
CTE
diagnosis
and
stage
IV
CTE.
Clinicians
who
were
masked
to
neuropathology
status
reviewed
brain
donors’
medical
records
and
clinical
histories
from
family
members
and
others
to
determine
a
dementia
diagnosis.

To
account
for
selection
pressure
of
brain
donation
status,
inverse
probability
weighting
was
used
to
estimate
the
association
between
stage
IV
CTE
and
study
clinician-diagnosed
dementia.

Among
brain
donors,
30.8%
had
stage
IV
CTE;
59.8%
had
dementia
according
to
a
study
clinician,
and
18.6%
had
neurodegenerative
disease
listed
as
primary
cause
of
death.
Those
with
dementia
had
onset
at
age
63
and
died
at
age
73.

“Only
40.6%
of
donors
(n=82)
with
study
clinician-diagnosed
dementia
had
neurodegenerative
disease
listed
as
the
primary
or
secondary
cause
of
death,”
Daneshvar
and
co-authors
observed.

The
researchers
acknowledged
several
limitations
to
their
analysis.
Not
all
former
NFL
players
who
died
during
the
study
window
were
included;
at
least
11
other
cases
of
CTE
in
NFL
players
who
died
were
reported
in
the
literature
or
by
family
members
but
were
not
incorporated
into
the
study
to
maintain
consistent
methodology.
In
addition,
some
family
members
or
other
informants
may
have
inaccurately
recalled
symptoms.

“These
data
provide
insight
into
the
extent
to
which
the
higher
proportions
of
death
due
to
neurodegenerative
disease
are
associated
with
CTE
pathology
and
provide
targets
for
future
research
studies
and
policy
recommendations,”
Daneshvar
and
colleagues
wrote.

More
work
is
needed
to
clarify
the
possible
effects
of
high
lifetime
exposure
to
repetitive
head
impacts,
especially
in
other
populations,
they
added.

Please
enable
JavaScript
to
view
the

comments
powered
by
Disqus.