Experts agree that brain injuries, like concussions, tend to be bad for your health. As it turns out, the effects might be longer-lasting than just the typical concussion symptoms: Researchers at the Mayo Clinic have found a link between concussions and the buildup of plaques in the brain typically associated with Alzheimer’s disease.

“What we think it suggests is, head trauma is associated with Alzheimer’s-type dementia — it’s a risk factor,” said study researcher Michelle Mielke, an associate professor of epidemiology and neurology at Mayo Clinic Rochester. “But it doesn’t mean someone with head trauma is [automatically] going to develop Alzheimer’s.”

Mielke notes that the study shows correlation, not causation. Previous studies on the subject of Alzheimer’s and concussions have returned conflicting results.

The study, based out of Olmsted County, Minnesota, examined 448 people without any signs of memory problems and 141 people with memory and thinking problems called mild cognitive impairment. All participants were aged 70 or over, and researchers asked each of them if they had any history of brain injury that involved the loss of memory or consciousness. Of those with no memory issues, 17% reported brain injuries. 18% of those with thinking or memory complications had a history of brain injury.

Among those without memory problems, brain scans showed no difference between those who reported brain injuries and those who hadn’t. However, those with cognition issues showed higher instances of amyloid plaques, commonly associated with Alzheimer’s disease. Plaques are deposits of a protein fragment known as beta-amyloid that can build up in between the brain’s nerve cells. While most people develop some with age, those who develop Alzheimer’s generally get many more, according to the Alzheimer’s Association.

Though the study establishes a clear link, the results are far from definitive.

“Our results add merit to the idea that concussion and Alzheimer’s disease brain pathology may be related,” Mielke 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.”

The study adds valuable information for experts in the field, said Dr. Robert Glatter, director of sports medicine and traumatic brain injury in the department of emergency medicine at Lenox Hill Hospital, in New York City. Glatter, who is also a former sideline physician for the National Football League’s New York Jets, reviewed the new study findings. Most studies, he noted, rely on data from postmortem subjects.

According to the Alzheimer’s Association, More than 5 million Americans have Alzheimer’s disease