What do people with dementia or alzheimer's usually die of?

Pneumonia, often: People with dementia in very late stages often have difficulty with eating ; swallowing -- making them predisposed to aspirating food. This can result in aspiration pneumonia, which can kill them. Of course there are other types of infections and medical problems (like strokes, pulmonary emboli, heart attacks, etc) that can be deadly as well.

See below: The most common cause of death is the following: failure to thrive, sepsis and myocardial infarction. It is very difficult to pinpoint the specific cause of death.