Study of older veterans links brain injury, dementia risk

A large study in older veterans indicates that mild brain injuries seem to raise the risk of developing Alzheimer's disease or other dementia later in life.

Closed-head, traumatic brain injuries are a legacy of the Afghanistan and Iraq wars, with hundreds of thousands of troops having suffered from explosions in recent wars. Body armor is helping troops survive bomb blasts, but the long-term effects of their head injuries are unknown.

Other research found a possibly high rate of mild cognitive impairment, or "pre-Alzheimer's," in some retired pro football players, who take many hits to the head in their careers.

The new study results, reported Monday at the Alzheimer's Association International Conference in France, challenge the current view that only moderate or severe brain injuries predispose people to dementia.

"Even a concussion or a mild brain injury can put you at risk," said Laurie Ryan, a neuropsychiatrist who used to work at Walter Reed Army Medical Center and now oversees Alzheimer's grants at the National Institute on Aging.

In a separate study about five years ago, physicians at Richmond's McGuire Veterans Affairs Medical Center found that some older patients who had suffered seizures as a result of traumatic brain injuries also had some form of dementia.

This doesn't mean that every soldier or student-athlete who has had a concussion is in danger, but it does mean you should try to avoid one, by fall-proofing your home and wearing safety helmets and seat belts, said William Thies, the Alzheimer's Association's scientific director. About 1.7 million brain injuries occur each year in the U.S.

Troops also need to prevent any further harm, said Dr. David Cifu, national director of physical medicine and rehabilitation for the Veterans Health Administration, who is based at McGuire.

"What the people who have had a head injury and read this should do is to exercise and eat right and take their medicines and take their aspirin and do meditation to reduce stress — reduce risk factors that are modifiable," he said. The new study is "a great start," but limitations in its methods mean that it can't prove a brain injury and dementia link, he said. More definitive studies are starting now but will take many years to give results.

Dr. Ajit Pai is the director of the Inpatient Polytrauma Unit at McGuire, one of four such units specializing in treating service members with traumatic brain injury along with other major injuries.

"There's a vast number of patients out there that are active-duty service members that are getting multiple concussions or multiple exposures to blast injury," he said.

The long-term effects are unclear, Pai said. "Whether that means seizures down the line or movement disorders down the line or Alzheimer's down the line, we just don't have all that data yet," he said.

"Our hope is that we can avert the potential negative consequences of aging brain-injured patients by following them closely and really figuring out what problems are arising and focusing on them and treating them and managing them," he said.

Dr. Alan Towne, chief of neurology and head of McGuire's Epilepsy Center of Excellence, said, "We know from past experience there's an increase in the number of soldiers that develop epilepsy after receiving traumatic brain injuries. Usually, you don't see it right away. … It could take years."

The new veterans study was led by Dr. Kristine Yaffe, a University of California professor and director of the Memory Disorders Clinic at the San Francisco VA Medical Center, who said it's the largest study of brain injury and dementia risk. The Department of Defense and the National Institutes of Health paid for the work.

Researchers reviewed medical records on 281,540 veterans who got care at Veterans Health Administration hospitals from 1997 to 2000 and had at least one follow-up visit from 2001 to 2007. All were at least 55 and none had been diagnosed with dementia when the study began. This older group was chosen because dementia grows more common with age, and researchers needed enough cases to compare those with and without brain injuries.

Records showed that 4,902 of the veterans had suffered a traumatic brain injury ranging from concussions to skull fractures. Researchers don't know how long ago the injuries occurred. Many participants were Vietnam War vets, and their injuries were suffered during active duty. None were from strokes — those cases were weeded out.

Over the next seven years, more than 15 percent of those who had suffered a brain injury were diagnosed with dementia versus only 7 percent of the others — a more than doubled risk. Severity of the injury made no difference in the odds of developing dementia.

That worries Ryan Lamke, 26, a medically retired Marine who lives in suburban Washington. He suffered a traumatic brain injury from multiple blast exposures in 2005 in Iraq. He's now a student at Georgetown University and works part time as a government relations intern for a private firm.

"I have to read for twice as long as my classmates" to accomplish what's needed, he said. "I've not found a doctor so far who can give me a true understanding of what's going to happen 20 or 30 years down the road."

The other study is follow-up work on nearly 4,000 retired National Football League players surveyed in 2001. New surveys were sent in 2008 to 905 of them who were older than 50.

"We were surprised that 35 percent of them appeared to have significant cognitive problems," said the lead researcher, Dr. Christopher Randolph of Loyola University Medical Center in Chicago.

Researchers sent 41 of them to the Center for the Study of Retired Athletes at the University of North Carolina in Chapel Hill. Tests showed they had mild cognitive impairment that resembled a comparison group of much older patients from the general population.