Not necessarily. Having a parent, especially a mother, with Alzheimer's is a known risk factor. But this doesn't mean that you will automatically get the disease. The cause of Alzheimer's isn't known and the role of heredity is unclear.

There is a proven genetic link to certain kinds of relatively rare, early-onset Alzheimer's. A genetic test will reveal if you carry forms of the apolipoprotein gene, APOE4, which raises the risk of disease. But almost half of people who carry this gene do not develop Alzheimer's.

Even someone with a possible genetic link seems to be able to lower his or her odds of developing the disease through such lifestyle strategies as maintaining a healthy weight, exercising regularly, keeping blood sugar and blood pressure in normal ranges, and staying socially active and intellectually stimulated.