People who had concussions can be at a higher risk of developing plaques on the brain found in people with Alzheimer’s disease, according to a study featured in the journal Neurology, Fox News reports.

The new research released today examines the relationship between concussions and amyloid beta plaques in the brain. While the study couldn’t prove causation, it helps shed light into the possible long-term effects of traumatic brain injuries.

Study author Michelle Mielke, a researcher at the Mayo Clinic, scanned the brains of 589 people ages 70 or older. Of those, 141 had symptoms of mild cognitive impairment. All were asked about whether they’d suffered a concussion in the past.

Researchers found the 17 percent of the 448 people without thinking or memory problems reported a brain injury, while 18 percent of the 141 people with memory problems reported a concussion or other head trauma.

Those with memory and thinking impairments and a history of head trauma had an average of 18 percent more amyloid beta plaques—the hallmark of Alzheimer’s disease—than those with no history of head trauma.

 “It’s an interesting piece of an overall puzzle,” said Keith Fargo, director of publications and outreach for the Alzheimer’s Association. “We’re glad people are doing research in this area. We need to know more about head injury and dementia later in life.”