How long a person with Alzheimer's will live is highly dependent on the person's age at the onset of the disease as well as what medical problems the person is experiencing in addition to Alzheimer's. Those with multiple medical conditions tend to die sooner than those who have no other physical problems. Individuals with Alzheimer's disease often die of a medical complication such as pneumonia or the flu. However, Alzheimer's is fatal -- if there are no other complications, the person will die when all bodily systems fail because of the disease.
Sources:
Alzheimer's disease fact sheet. National Institutes of Health. July 2006.
Alzheimer's disease facts and figures. Alzheimer's Association. 2007. http://www.alz.org/national/documents/report_alzfactsfigures2007.pdf
