The report looked at traumatic brain injury (TBI), which includes
concussions, skull fractures and bleeding inside the skull.
“There have been a fair number of previous studies that have looked
at the relationship between TBI and risk of dementia, and some have
found an association while others haven't,” said lead author Deborah
E. Barnes, from the University of California, San Francisco and the
San Francisco Veterans Affairs Medical Center.
She and her colleagues sought to clarify the relationship by taking
into account other conditions, like depression and post-traumatic
stress disorder (PTSD).
“And we found that, even after accounting for these other factors,
older veterans with a history of TBI were 60 percent more likely to
develop dementia,” Barnes told Reuters Health in an email.
Dementia affects five percent of people in their 70s and 37 percent
of those in their 90s, according to past research.
For the new study, the researchers examined the medical records of
more than 188,000 U.S. veterans ages 55 and older who had undergone
a medical evaluation between 2000 and 2003 and did not have dementia
at the time.
The veterans all visited the doctor again at least once between 2003
According to their records, 1,229 of the veterans had been diagnosed
with TBI. Between 2003 and 2012, 196 of those with a history of TBI
developed dementia, or 16 percent, compared to 18,255 of the
veterans without TBI, or 10 percent.
Veterans with TBI also developed dementia an average of two years
earlier than those without TBI, according to results published in
“Of course, these numbers reflect population averages, so there will
be many individual veterans without TBI who develop dementia and
many with TBI who don't,” Barnes said. “Having a TBI just increases
Veterans with head injuries in the study were more likely than
uninjured veterans to have other health problems including diabetes,
high blood pressure, depression and PTSD.
“Head trauma is pretty controversial still,” said Dr. Rodolfo Savica
of the University of Utah School of Medicine in Salt Lake City.
“We know it can increase risk of dementia in the long run, but not
everybody who is exposed to this trauma develops problems,” Savica,
who wrote an editorial accompanying the study, told Reuters Health.
[to top of second column]
Other health issues that exist alongside head trauma are also
important, he said.
Since veterans with TBI were more likely to have diabetes and high
blood pressure as well, this is likely a group that is more prone to
disease or more vulnerable, Savica said.
“We should follow up more carefully with these people,” he said.
“Whenever you have additional (health issues), if you are depressed
or have PTSD, you have to tell your doctor.”
Head injuries are common among both veterans and non-veterans,
affecting as many as one in five Iraq and Afghanistan vets, Barnes
Veterans with head injuries may be able to lower their risk of
dementia by engaging in physical, mental and social activities,
making sure high blood pressure and diabetes are well controlled and
getting treatment for any mental health conditions such as
depression and PTSD, she said.
“We found that there was an additive relationship between mental
health conditions and head injury, so that veterans who had both of
these risk factors were more likely to develop dementia than those
who only had one,” Barnes said.
“In addition, they may be able to lower risk of dementia by doing
their best to minimize future head injuries by doing simple things
to protect their brain, like wearing helmets and seat belts,” she
Neurology, online June 25, 2014.
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