A serious concussion early in life could contribute to Alzheimer's risk decades down the line, according to a new study from the Mayo Clinic in Rochester, Minn.
Researchers publishing in Neurology found that elderly people who tested for memory and cognitive problems and recalled suffering from at least one serious concussion in their youths also had higher levels of amyloids, a fibrous protein deposit that's associated with Alzheimer's disease.
Researchers believe that concussions damage the myelin coating within neurons, reported the Los Angeles Times, and that this damage may have encouraged higher amyloid levels among the impaired group.
The study involved a total of 589 septuagenarian and octogenarian Minnesotans. After a series of cognitive tests, researchers determined that 141 of the study participants had memory or thinking problems, while the remaining 448 had healthy cognitive functioning. Approximately 17 percent of the healthy group and 18 percent of the problem group reported having had, at some point in their lives, a concussion severe enough that they lost consciousness or memory.
Since the cognitively healthy group suffered from serious concussion at nearly the same rate as the problem group, the study did not determine a definitive link between loss of consciousness and Alzheimer's risk. Instead, researchers interpreted the results as another clue into the complex group of factors that leads to dementia in old age.
"Our results add merit to the idea that concussion and Alzheimer's disease brain pathology may be related," study author Michelle Mielke, Ph.D. said in a statement. "However, the fact that we did not find a relationship in those without memory and thinking problems suggests that any association between head trauma and amyloid is complex."
Although this is one of the first studies to measure amyloid build up via brain scan, several studies have previously investigated the link between head trauma and Alzheimer's risk. Research in mice and in post-mortem brain samples found a connection between head trauma and Alzheimer's and a 2013 analysis of brain scans of concussion patients found that they looked similar to the brain scans of Alzheimer's patients.
"In my view, these findings are consistent with the idea that traumatic brain injury may lead to amyloid accumulation and Alzheimer's disease," Richard Lipton, director of the Division of Cognitive Aging and Dementia and the Montefiore Headache Center at Albert Einstein College Of Medicine in New York City, told USA Today, adding that once a more definitive link had been determined, researchers could use studies like this to help create treatments to block the development of amyloid build-up.