Even a mild concussion could put you at greater risk for Alzheimer’s disease, a new study has suggested.

Findings published in the journal Brain say moderate to severe brain injury is already noted as something that can contribute to that type of dementia and other neurodegenerative diseases, but mild trauma is also “associated with greater neurodegeneration and reduced memory performance” in people who have a genetic risk of developing Alzheimer’s. That disease is marked by a loss of memory, but also degrades other mental functions over time.

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During their study, researchers measured the thickness of the layers within the brain’s cerebral cortex, which is involved in memory, language and other types of thought, in the brains of Iraq and Afghanistan war veterans. That measurement is important because in certain places within the cerebral cortex, it begins to thin and atrophy in the early stages of Alzheimer’s. Many of the 160 veterans, according to the study, were previously diagnosed with at least one concussion and post-traumatic stress disorder, the mental illness linked to traumatic experiences. The authors say they found that concussions were associated with a reduced thickness in those brain regions, and may even speed up the process.

“These results underscore the importance of documenting head injuries even within the mild range, as they may interact with genetic risk to produce negative long-term health consequences such as neurodegenerative disease,” the study says.

The next step for the research team is to find out what exactly about a concussion speeds up the onset of Alzheimer’s, Boston University Medical Center said in a statement. That information could lead to medications that prevent the process, and help doctors detect these effects of a concussion as early as possible — the average age of the veterans found with changes in their brains was just 32.

“Even if the person ... is able to shake it off fairly quickly,” corresponding author Jasmeet Hayes said in the statement, “the concussion may produce negative long-term health consequences” when combined with other factors like genetic risk.

Scientists are getting closer all the time to predicting and learning about the onset of Alzheimer’s. In one recent study, the researchers found a protein in their patients’ cerebrospinal fluid that indicated an immune system response — one that could be linked to the onset of Alzheimer’s.

Source: Hayes JP, Logue MW, Sadeh N, et al. Mild traumatic brain injury is associated with reduced cortical thickness in those at risk for Alzheimer’s disease. Brain. 2017.

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