Individuals with memory and thinking problems who also have a history of concussions may be at a higher risk of developing Alzheimer's disease later in life, according to a new study from the Mayo Clinic.
The study, published Thursday online in the journal Neurology, suggests a history of brain trauma could be related to Alzheimer's-related plaque buildups in the brain. Researchers studied 448 individuals with no signs of memory or thinking problems, and 141 who had reported memory and thinking problems. All participants were over the age of 70 and were asked if they had ever experienced a brain trauma that resulted in a loss of consciousness.
"Interestingly, in people with a history of concussion, a difference in the amount of brain plaques was found only in those with memory and thinking problems, not in those who were cognitively normal," study author Michelle Mielke said in a statement.
There is no cure for Alzheimer's and the memory loss becomes more severe with time. According to the Alzheimer's Association, more than 5 million Americans are living with the disease, which is the sixth leading cause of death in the country. The disease is the most common type of dementia, and accounts for about 50 to 80 percent of all dementia cases.
Brain plaques -- deposits of the protein fragment beta-amyloid -- and twisted fibers known as tangles are responsible for damaging and killing nerve cells in the brain, which causes memory loss. People with Alzheimer's disease tend to develop far more brain plaques than older adults normally do, according to the Alzheimer's Association.
In the Mayo Clinic study, 17 percent of the people with no memory problems said they had experienced a head trauma, while 18 percent of those with memory problems said they had experienced a concussion or other head trauma. The researchers found those elderly adults with both thinking and memory problems and a history of head injury had plaque buildups an average of 18 percent higher than those without a head trauma history.
"Our results add merit to the idea that concussion and Alzheimer's disease brain pathology may be related," Mielke said. "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."