Alzheimer's: Can a head injury increase my risk?

Can a head injury cause or hasten Alzheimer's disease or other types of dementia?

- Penny / Michigan

Mayo Clinic neuropsychologist Glenn Smith, Ph.D., and colleagues answer select questions from readers.

Answer

It depends on your age at the time of your head injury, the severity of the head injury and possibly your genetic makeup.

Keep in mind that brain damage from a head injury itself is a potential cause of dementia. Dementia is present when there is a decline in two or more thinking skills — such as memory and reasoning — resulting in a person being unable to perform his or her normal, daily activities. However, dementia caused by a head injury typically is a stable condition, meaning it doesn't worsen over time.

In terms of progressive dementia, such as Alzheimer's disease, an overview of research suggests that head injuries early in life — such as before age 50 — do not significantly increase the risk of Alzheimer's disease later in life. But head injuries later in life may increase the risk of Alzheimer's disease in part by hastening the onset or awareness of symptoms. Also, emerging evidence suggests that certain genes — such as the apolipoprotein E (APOE) gene — can increase or decrease your risk of Alzheimer's after a head injury.