|
New study at UNC shows concussions
promote dementias in retired professional football players.
CHAPEL HILL Repeated concussions brought on by blows to
the head during their playing days significantly boost the
chances that retired professional football players will
suffer dementias such as mild cognitive impairment in later
life, a new study suggests.
The study, conducted by University of North Carolina at
Chapel Hill researchers and colleagues, found that retired
National Football League players also faced a 37 percent
higher risk of Alzheimer's than other U. S. males of the
same age.
A report on the findings, which are being presented at
a Congress of Neurosurgery scientific meeting in Boston
today (Oct. 10), appears in the October issue of the journal
Neurosurgery. Lead authors are Drs. Kevin M. Guskiewicz,
professor of exercise and sport science in the UNC College
of Arts and Sciences, and Stephen W. Marshall, associate
professor of epidemiology at the UNC School of Public Health
and of orthopaedics at the UNC School of Medicine. Guskiewicz
also chairs the exercise and sport science department, directs
the university's Center for the Study of Retired Athletes
and Sports Medicine Research Laboratory and holds a joint
appointment in othopaedics.
"In this unique study, we had some very interesting
findings," Guskiewicz said. "Our data suggest
that a history of recurrent concussions and probably sub-concussive
contacts to the head may be risk factors for the expression
of late-life memory impairment, mild cognitive impairment
and earlier expression of Alzheimer's disease. Research
like this is important since more than 300,000 sport-related
concussions, many of which are recurrent injuries, occur
annually in the U.S. and more than 1.2 million Americans
suffer head injury each year."
The study involved surveying by mail 3,683 retired professional
football players who belonged to the NFL Retired Player's
Association about their overall health and analyzing the
results.
Of those, 2,552 returned questionnaires or had their spouses
or other close relatives do so for about a 70 percent response
rate. Players averaged almost 54 years old and had an average
professional career spanning 6.6 years.
Researchers then surveyed a subset of 758 players aged
50 and older and asked more detailed questions about concussions
and diagnosed dementia-related impairments. Spouses and
close relatives also participated and assisted in confirming
responses provided by the retired players.
"When considering prevalence of previous concussions,
1,513, or 60.8 percent, of the retired players reported
having sustained at least one concussion during their professional
playing career, and 597, or 24 percent, reported sustaining
three or more concussions," Guskiewicz said.
Among retired players who sustained a concussion during
their professional careers, more than half reported experiencing
loss of consciousness or memory loss from at least one of
their concussions, he said.
"We asked the retired players for their subjective
assessment of the long-term consequences of their injuries,"
Guskiewicz said. "Of the retirees who sustained at
least one concussion, 266, or 17.6 percent, reported that
they perceived the injury to have had a permanent effect
on their thinking and memory skills as they have gotten
older. The findings showing a relationship between diagnosed
mild cognitive impairment and history of concussions --
three or more -- suggest that a true memory effect is present."
Retired players with three or more concussions had a five-fold
greater chance of having been diagnosed with mild cognitive
impairment and a three-fold prevalence of reported significant
memory problems compared to those players without a history
of concussion, he said. Physicians had diagnosed 33 players
with Alzheimer's. The higher prevalence of the memory-destroying
disease was more noticeable in the younger age groups --
those below age 70 than in those over that age.
Co-authors of the report are Dr. Julian Bailes of the West
Virginia University School of Medicine, Dr. Michael McCrea
Waukesha Memorial Hospital and the Medical College of Wisconsin
in Milwaukee, Dr. Robert C. Cantu of Emerson Hospital in
Concord, Mass., and Brigham and Women's Hospital in Boston,
Dr. Christopher Randolph of the Chicago Neurological Institute
and Loyola University Medical School in Maywood, Ill., and
Barry D. Jordan of Burke Rehabilitation Hospital in White
Plains, N.Y.
The study's chief limitation was that it was based on self-reported
answers to the health questions, and the accuracy of remembering
memory problems could not be verified completely.
"Future prospective studies should implement genetic
testing since genes are known to affect memory," Guskiewicz
said. "Also, there needs to be more rigorous diagnostic
criteria, historical documentation of injuries and periodic
evaluations such as neurophysiologic testing and functional
neuroimaging to clarify the effects of concussion on lifetime
risk of dementia or other neurologic disorders."
|
