Is diabetes a risk factor for alzheimers?

Yes: Yes it is. Both diabetes and alzheimer's involve excessive inflammation, although the precise link is not clear. Diabetes accelerates vascular disease and there could be elements of brain ischemia that promote alzheimers.

Not exactly: Diabetes is a risk factor for vascular disease, which then causes dementia....Most commonly vascular dementia; the exact relationship between the development of true alzheimer's and other factor is not established yet...