May 4, 2009 -- Question: Could a previous head injury affect my risk of developing Alzheimer's disease?
Answer: Head injuries can affect your chances of developing Alzheimer's disease or other kinds of late-life losses of thinking function -- in different ways. The way that is most well known is that people who have suffered a head injury, in which they have been unconscious for at least a half an hour, have a clear increase in the likelihood that they woulddevelop Alzheimer's disease.
However, when we look at the data, it appears that these are possibly people who would've developed Alzheimer's disease at some point in the future. And that the combination of that relatively serious head injury and their predisposition to develop Alzheimer's disease combined so that you would actually get the disease a few years earlier that you might have gotten it had you not had a head injury.