There has been growing concern about concussive injuries and neurological problems later in life — last week, the NFL and the National Institutes of Health announced they will team up to further much needed research on the subject.

But a current study funded by the NIH and published in the journal Neurology shows a link between concussions and Alzheimer’s in older Americans.

Michelle Mielke, associate professor of epidemiology and neurology at Mayo Clinic Rochester led a team that studied 448 Minnesota residents over the age of 70 who had no cognitive impairment and compared them with 141 others who had mild impairment. The participants underwent a brain scan to determine whether or not older Americans with a history of concussion had a greater build up of beta-amyloid plaques in the brain; beta-amyloid build-up is what causes cognitive impairment in Alzheimer’s patients.

The results were dramatic — those who had a history of head trauma had 5 times the beta-amyloid buildup compared to those who did not have a concussion history. Although Mielke concludes that concussion is definitely a risk factor, the link her team discovered was associative, not causal. In other words, concussions don’t necessarily cause Alzheimer’s, but they do in fact, increase risk of the disease.

According to Mielke, all adults advanced in age have some beta-amyloid build up in the brain; however, in those who develop Alzheimer’s the buildup begins predictably, starting in the area of the brain that controls memory.

The study is important because various studies in the past have produced conflicting results, Mielke states. Additionally, the study is unique because the participants were living — most research on Alzheimer’s have been conducted post-mortem.