Alzheimer's disease is a progressive illness caused by the destruction of brain cellsleading to loss of memory and other cognitive defects, advancing to personality changes and loss of control over bodily functions. The loss of smell or olfactory function has been known to be an early sign of some degenerative diseases for over a decade but it can't be directly linked to Alzheimer as a reference. In other words people who have experienced loss of smell are not guaranteed to contract this disease in their lifetime.